Showing papers in "Journal of Prosthetic Dentistry in 2005"

The glossary of prosthodontic terms.

Abstract: A Abbe flap \ăb# e flăp\ [Robert Abbe, New York, N.Y. surgeon, 18511928]: eponym for a lip switch operation. A triangular, full thickness flap from the lower lip used to fill in a deficit in the upper lip. Specifically applied to the midportion of the upper or lower lip— called also lip switch operation Abbe, R. A new plastic operation for the relief of deformity due to double harelip. Med Rec 1898;53:477. ab duct \ăb dŭkt#\ vt (1834): to draw away from the median plane— comp ADDUCT ab er rant \ă-bĕr#ant\ adj (ca. 1798)1: a deviation from the normal or usual course, form, or location 2: straying from the normal way ab frac tion \ăb frăk#shun\ n (1991): the pathologic loss of hard tooth substance caused by biomechanical loading forces. Such loss is thought to be due to flexure and chemical fatigue degradation of enamel and/or dentin at some location distant from the actual point of loading—comp ABLATION, ABRASION, ATTRITION, and EROSION ab la tion \ă-bl a#shun\ n (15c) 1: separation or detachment; extirpation; eradication 2: removal of a part, especially by cutting—see ABFRACTION, EROSION abrade \uh-br ad#\ vt (1677): to rub away the external covering or layer of a part—comp ATTRITION, EROSION abra sion \ă-br a #shun\ n (1656) 1: the wearing away of a substance or structure (such as the skin or the teeth) through some unusual or abnormal mechanical process 2: an abnormal wearing away of the tooth substance by causes other than mastication—comp ATTRITION, EROSION abra sive \uh-br a # siv, -ziv\ n (1853): a substance used for abrading, smoothing, or polishing abra sive \uh-br a # siv, -ziv\ adj (1875) 1: tending to abrade 2: causing irritation—abra sive ly adv, abra sive ness n ab ra si vity \uh-br a#siv-ı̆-t e, -ziv-ı̆-t e\ v (1998): the property of one material to wear away another material by means of frictional contact absorbed dose \ab-sôrbd#,-zôrbd# d os\: the amount of energy from ionizing radiation absorbed per unit mass of matter, expressed in Gray units ab sorp tance \ab-sôrp#tans, -zôrp#tans\ n (ca. 1931): the ratio of the radiant energy absorbed by a body to that incident upon it ab sorp tion \ab-sôrp#shun, -zôrp#-\ n (1741) 1: the uptake of substances into or through tissues, e.g., mucosa, skin, and intestine 2: in radiology, the uptake of energy by matter with which the radiation interacts—see A. of RADIATION—comp ADSORPTION absorption of radiation \ab-sôrp#shun ŭv r a#d ea#shun\: collisionlike interactions between the individual particulate or quantum components of a beam of radiation and the subatomic parts of matter that occur at random during irradiation. Each interaction may result in partial or complete transfer of energy abut ment \a-bŭt#ment\ n (1634) 1: that part of a structure that directly receives thrust or pressure; an anchorage2: a tooth, a portion of a tooth, or that portion of a dental implant that serves to support and/or retain a prosthesis—usage see ANGULATED A., HEALING A., DENTAL IMPLANT A., INTERMEDIATE A., ONE PIECE A., PREPARATION PIECE A., STANDARD A., TWO PIECE A. DropB

Effects of different drinks on stainability of resin composite provisional restorative materials.

Abstract: Statement of problem The ability of tooth-colored restorative materials for provisional restorations to resist stains is important when interim prostheses are worn for a long period. Discoloration of provisional restorative materials may result in patient dissatisfaction and additional time and expense for replacement. However, the effect of different staining agents on the color difference of resin composite restorative materials has not been completely clarified. Purpose The purpose of this study was to evaluate the stainability of auto- and light-polymerized composite provisional restorative materials, reinforced microfill, and microhybrid resin composite restorative materials upon exposure to different staining agents. Material and methods Forty-five cylindrical specimens (15 × 2 mm) were prepared for each of an autopolymerized bis-acryl composite provisional restorative material (Protemp II), a light-polymerized composite provisional restorative material (Revotek LC), a reinforced microfill (Micronew), and a microhybrid composite (Filtek Z250, Herculite XRV) restorative material, using a brass mold. The specimens were wet-ground with 1000-grit silicon carbide abrasive paper for 10 seconds. The 5 restorative material specimens were divided into 9 groups (n=5) and stored for 24 hours at 37°C in different types of solutions: water, coffee, coffee with sugar, tea, tea with sugar, coffee with artificial creamer and sugar, cola, red wine, or sour cherry juice. Color of all specimens was measured before and after exposure with a colorimeter using CIE L ∗ a ∗ b ∗ relative, and color changes (ΔE ∗ ) were then calculated. The data were analyzed with a 2-way analysis of variance (ANOVA), and mean values were compared by the Tukey HSD test (α=.05). Results The interaction of provisional restorative materials and staining agents was statistically significant ( P =.0001). For the 5 restorative materials tested, the lowest ΔE ∗ values were observed in the water, cola, and sour cherry juice groups. The highest color difference for all restorative materials was observed in the red wine groups. For microhybrid composite materials and light-polymerized composite provisional material, when tea and coffee groups with and without sugar were compared, both groups with sugar demonstrated a higher color difference than without sugar. When comparing the 5 different restorative materials, the reinforced microfill material group (Micronew) demonstrated significantly less color change than the other materials tested. The highest color difference in this study was observed for specimens in the light-polymerized composite provisional material group (Revotek LC). Conclusion The reinforced microfill restorative material tested was found significantly more color stable than the autopolymerized bis-acryl, light-polymerized composite provisional restorative materials, and microhybrid composites tested. The largest color difference was observed in the light-polymerized composite provisional material. The presence of sugar in coffee and tea increased the color difference compared to coffee or tea without sugar for light-polymerized composite provisional material and microhybrid composites.

Finite element analysis of stresses in endodontically treated, dowel-restored teeth

Abstract: Statement of problem Endodontically-treated, dowel-restored teeth may experience fracture, but investigations of variables related to fracture are often inconclusive and occasionally contradictory. Purpose The finite element method was used to analyze the stresses in dowel-restored teeth. The variables studied were material, shape, bonding, modulus of elasticity, diameter, and length of the dowel. Material and methods The model of the dowel-restored tooth involved dentin, ligament, cortical and trabecular bone, gingiva, and gutta-percha. The dowels were made of glass fiber, titanium, or zirconia and modeled as an approximation of the brands ParaPost Fiber White, ParaPost XH, and Cerapost, respectively. The dowel was cemented with zinc-phosphate cement or with bonded or nonbonded resin luting agents, and an approximation of the material properties of these 2 materials were used in the modeling. The restoration included a composite resin core and a gold crown. Other variables included taper versus parallel-sided posts, modulus of elasticity, diameter, and length of post. The model was axisymmetrical in 3 dimensions. A load of 100 N was applied to the crown at an angle of 45 degrees, and tensile, shear, and von Mises stresses were calculated. Results The generated stresses decreased with respect to the dowel material in the following order: glass fiber, titanium, and zirconia. Stresses were in general higher with tapered than with parallel-sided dowels. Stresses were reduced by bonding and with an increasing modulus of elasticity, increasing diameter, and increasing length of the dowel. Conclusions Within the limitations of this study, it was found that all investigated dowel-related factors influenced the stress field generated in dowel-restored teeth.

Three-dimensional finite element analysis of the effect of different bone quality on stress distribution in an implant-supported crown.

Abstract: Statement of problem Primary implant stability and bone density are variables that are considered essential to achieve predictable osseointegration and long-term clinical survival of implants. Information about the influence of bone quality on stress distribution in an implant-supported crown is limited. Purpose The purpose of this study was to investigate the effect of 4 different bone qualities on stress distribution in an implant-supported mandibular crown, using 3-dimensional (3-D) finite element (FE) analysis. Material and methods A 3-D FE model of a mandibular section of bone with a missing second premolar tooth was developed, and an implant to receive a crown was developed. A solid 4.1 × 10-mm screw-type dental implant system (ITI; solid implant) and a metal-ceramic crown using Co-Cr (Wiron 99) and feldspathic porcelain were modeled. The model was developed with FE software (Pro/Engineer 2000i program), and 4 types of bone quality (D1, D2, D3, and D4) were prepared. A load of 300 N was applied in a vertical direction to the buccal cusp and distal fossa of the crowns. Optimal bone quality for an implant-supported crown was evaluated. Results The results demonstrated that von Mises stresses in D3 and D4 bone quality were163 MPa and 180 MPa, respectively, and reached the highest values at the neck of the implant. The von Mises stress values in D1 and D2 bone quality were 150 MPa and 152 MPa, respectively, at the neck of the implant. A more homogenous stress distribution was seen in the entire bone. Conclusion For the bone qualities investigated, stress concentrations in compact bone followed the same distributions as in the D3 bone model, but because the trabecular bone was weaker and less resistant to deformation than the other bone qualities modeled, the stress magnitudes were greatest for D3 and D4 bone.

Immediate and early implant loading protocols: a literature review of clinical studies.

Abstract: The purpose of this literature review is to present the outcomes of clinical studies on immediate and early loading protocols, identify shortcomings, and suggest a number of questions that still require exploration. English language clinical studies, limited to peer-reviewed journals between 1975 and 2004, were reviewed to identify treatment outcomes with these loading protocols. The data were tabulated from studies reporting on patients treated with fixed and overdenture prostheses. The former included partially edentulous patients treated with single or multi-unit prostheses. Within the limitations of this review, it can be concluded that these treatment protocols are predictable in the anterior mandible, irrespective of implant type, surface topography, and prosthesis design (success rates 90%-100%). Limited evidence for the edentulous maxilla (success rates 90%-100%) and the partially edentulous patient (success rates 93%-100%) are available, underscoring the need for further research. Studies suggest that to achieve predictable results in extraction sites, implant placement should be restricted to sites without a history of periodontal involvement (success rates 61%-100%). A number of questions require further exploration. There is a need to thoroughly investigate clinical outcomes to measure the economic benefit of these protocols and the impact of treatment on a patient's quality of life. Furthermore, more accurate long-term studies reporting on treatment protocols for separate clinical situations are required to allow meaningful comparisons.

An analysis of maxillary anterior teeth: facial and dental proportions.

Abstract: Statement of problem The size and form of the maxillary anterior teeth are important in achieving pleasing dental and facial esthetics. However, little scientific data have been defined as criteria for evaluating these morphological features. Purpose This study analyzed the clinical crown dimensions of maxillary anterior teeth to determine whether consistent relationships exist between tooth width and several facial measurements in a subset of the Turkish population. Material and methods Full-face and anterior tooth images of 100 Turkish dental students viewed from the front and engaged in maximum smiling were recorded with digital photography under standardized conditions. Gypsum casts of the maxillary arches of the subjects were also made. The dimensions of the anterior teeth, the occurrence of the golden ratio, the difference between the actual and perceived sizes, and the relationship between the anterior teeth and several facial measurements by gender were analyzed using the information obtained from both the computer images and the casts. One-sample, 2-sample, and paired t tests, and repeated-measures analysis of variance and Duncan multiple-range tests were performed to analyze the data (α=.05). Results The dimensions of the central incisors ( P P P Conclusion The maxillary central incisor and canine dimensions of men were greater than those of women in the Turkish population studied, with the canines showing the greatest gender variation. Neither a golden proportion nor any other recurrent proportion for all anterior teeth was determined. Bizygomatic width and interalar width may serve as references for establishing the ideal width of the maxillary anterior teeth, particularly in women.

Effect of implant size and shape on implant success rates: a literature review.

Abstract: Understanding and using biomechanical theories that effect endosseous implant design may improve the performance of implants in varying load conditions and allow the clinician to better apply this information with potentially improved success rates. The following article presents information from English peer-reviewed journals identified by a Medline search covering the years from 1974 through 2004, and attempts to integrate information available in the dental literature and address current controversies and issues in selecting diameter, length, and shapes of dental implants.

In vitro retentive strength of zirconium oxide ceramic crowns using different luting agents.

Abstract: Statement of problem In contrast to gold crowns, in vitro determination of the retentive strength of all-ceramic crowns is more difficult because components allowing connection to testing apparatus are not as easily integrated into the all-ceramic material. Nevertheless, retentive strength data are crucial for obtaining information about the potential clinical performance of luting cements for all-ceramic restorations. Therefore, a new in vitro model was necessary to evaluate the retentive strength of all-ceramic crowns. Purpose The purpose of this in vitro study was to determine the retentive strength of 4 resin-cement systems, a compomer, a glass-ionomer cement, a resin-modified glass-ionomer cement, and a self-adhesive resin for luting zirconium oxide ceramic crowns. Material and methods One-hundred-twenty extracted human teeth were randomly divided into 12 groups (n=10) and prepared in a standardized manner (5-degree taper, 3-mm occlusogingival height). All-ceramic crowns (Lava) were fabricated in a standardized manner for each tooth. The following cements and corresponding bonding regimens were used to lute the crowns to the teeth according to manufacturers' recommendations: CO, Compolute/EBS Multi; CO/RT, Compolute/EBS Multi/Rocatec; CB, Superbond CB CB/RT, Superbond CB CB/PL, Superbond CB PA, Panavia F; DC, Dyract Cem Plus/Xeno III; CH/PL, Chemiace II/Porcelain Liner M; RL, RelyX Luting, K/C, Ketac Cem/Ketac Conditioner; K, Ketac Cem; and RU, RelyX Unicem. After thermal cycling (5000 cycles, 5°C-55°C), the outer surfaces of the cemented zirconium oxide ceramic crowns were treated (Rocatec) to improve bonding and then placed into a low-shrinkage epoxy resin block (Paladur). The block/crown and tooth components for each specimen were connected to opposing ends of a universal testing machine so that crown retention could be measured. Crowns were removed from teeth along their path of insertion. The retentive surface area (mm 2 ) was determined individually for each tooth. Statistical analyses were performed using the Wilcoxon exact test, ( α =.05) and a Bonferroni correction ( α =.001). Results The median (minimum/maximum) retentive strength values (MPa) were as follows: CO, 1.7 (0.6/4.3); CO/RT, 3.0 (1.3/5.4); CB, 4.8 (3.7/7.9); CB/RT, 8.1 (4.2/12.7); CB/PL, 5.3 (3.7/10.2); PA, 4.0 (3.3/5.1); DC, 3.3 (2.1/5.6); CH/PL, 4.0 (1.3/6.3); RL, 4.7 (2.8/6.6); K/C, 1.8 (0.6/2.3); K, 1.9 (0.2/4.5); and RU, 4.8 (2.5/6.7). Superbond C&B (+ Rocatec) specimens showed the highest median retentive strength, but were not significantly different from Superbond C&B without Rocatec pretreatment of the all-ceramic crown's inner surface. Compolute specimens also did not benefit significantly from the Rocatec pretreatment. Within the materials used without pretreatment of the ceramic, Superbond C&B, Panavia, Dyract Cem Plus, RelyX Luting, and RelyX Unicem showed the highest median retentive strength values and were not significantly different. Conclusion Within the conditions of this study, the compomer-cement, the resin-modified glass-ionomer cement, and the self-adhesive resin luting agent had the same level of retentive quality as the resin luting agents, Superbond C&B, and Panavia. Rocatec pretreatment of the ceramic surface did not improve the retentive strengths of Compolute and Superbond C&B.

A clinical trial of patient satisfaction and prosthodontic needs with ball and bar attachments for implant-retained complete overdentures: three-year results.

Abstract: Statement of problem Few prospective trials of implant-retained mandibular dentures have evaluated the increase and duration of patient satisfaction, costs of denture maintenance in relation to different methods of attaching overdentures to implants, or the use of a reinforced framework. Purpose This report evaluates subjects' satisfaction and prosthodontic maintenance during a 3-year randomized clinical trial of implant-retained mandibular complete dentures, whether reinforced or not with a cast framework, and attached by bar-clip or 2.25-mm ball-spring matrices to endosteal dental implants. Materials and methods One hundred edentulous subjects, each having at least 1 year's experience with conventional complete dentures, were selected from respondents to a university dental clinic's request for volunteers. Candidates were examined to verify adequate mandibular bone and medical suitability for implants. Subjects then received 2 implants in the anterior mandible before being stratified by mandibular bone height and gender and assigned randomly to 1 of 4 treatment groups. Every subject received a new maxillary complete denture in addition to an implant-supported mandibular complete denture, with or without a reinforcing framework, connected to implants by either a bar-clip or a ball-spring patrix and matrix. The dentures were adjusted and repaired as needed. Subjects indicated on a visual analogue scale (VAS) satisfaction with conventional dentures prior to the study and then with new dentures at 1 month, 1 year, and 2 years. The results reported here are from the first 68 subjects observed for 3 years after receiving new dentures (19 subjects received new dentures less than 3 years before this analysis, and another 13 subjects were lost to follow-up). VAS scores are presented in simple tables and graphs, and results for different groups were compared using 2-sided nonparametric rank tests and repeated measures ANOVA. With respect to costs and maintenance, t tests were used to compare group means. Sample size and other design considerations used a .05 significance level. Results After receiving new dentures with mandibular implant supports, improved satisfaction "within subject" was prompt, durable, substantial, and statistically significant, regardless of the attachment mechanism, and with or without a reinforcing framework. In contrast, there were no notable satisfaction differences between the 2 attachment mechanisms, or with the presence or absence of a reinforcing framework, either at specific intervals after receiving the new dentures, or in repeated measures ANOVA. For both attachment groups, most denture adjustments occurred during the first year. This accounted for 81% of total adjustments during 3 years, when the 34 subjects in the ball-spring group and the 34 in the bar-clip group were combined. The mean numbers of adjustments per subject and associated clinical times did not differ significantly between the 2 groups. Conversely, denture repairs declined more slowly than adjustments. Almost all repairs (90%) occurred in the ball-spring group to correct problems with the attachments, 39% in the first year, and tapering off only slightly in the following 2 years. Over 3 years of follow-up, mean numbers of repairs per subject differed significantly between groups: 6.7 repairs per person in the ball-spring group, compared to 0.8 in the bar-clip group ( P P Conclusion Subjects were very satisfied with the new dentures, although the ball-spring attachment tested in this trial required substantially more repairs.

Flexural strength of a layered zirconia and porcelain dental all-ceramic system

Abstract: Statement of problem New processing techniques have facilitated the use of zirconia core materials in all-ceramic dental prostheses. Zirconia has many potential advantages compared to existing core materials; however, its performance when layered with porcelain has not been evaluated. Purpose This study investigated the strength of a wide variety of layered zirconia and porcelain beams to determine whether the inclusion of zirconia cores results in improved strength. Material and methods Eight types of layered or simple zirconia and porcelain beams (n=10), approximately fixed partial denture–size, were made of a tetragonal polycrystalline zirconium dioxide partially stabilized with yttria core (Lava System Frame) and a feldspathic dental porcelain (Lava Ceram veneer ceramic). Elastic moduli of the materials were measured using an acoustic method. Maximum force and modulus of rupture were determined using 3-point flexural testing and a universal testing machine. Descriptive statistical methods were used. Results Beams with porcelain tensile surfaces recorded mean tensile strengths or moduli of rupture from 77 to 85 MPa, whereas beams with zirconia tensile surfaces recorded moduli of rupture almost an order of magnitude higher, 636 to 786 MPa. The elastic moduli of the porcelain and zirconia materials were 71 and 224 GPa, respectively. Crack propagation following initial tensile cracking often involved the porcelain-zirconia interface, as well as bulk porcelain and zirconia. Conclusion The layered zirconia-porcelain system tested recorded substantially higher moduli of rupture than have been previously reported for other layered all-ceramic systems.

In vitro fracture resistance of endodontically treated central incisors with varying ferrule heights and configurations

Abstract: Statement of problem The in vitro effectiveness of a uniform circumferential ferrule has been established in the literature; however, the effect of a nonuniform circumferential ferrule height on fracture resistance is unknown. Purpose This in vitro study investigated the resistance to static loading of endodontically treated teeth with uniform and nonuniform ferrule configurations. Material and methods Fifty extracted intact maxillary human central incisors were randomly assigned to 1 of 5 groups: CRN, no root canal treatment (RCT), restored with a crown; RCT/CRN, no dowel/core, restored with a crown; 2 FRL, 2-mm ferrule, cast dowel/core and crown; 0.5/2 FRL, nonuniform ferrule (2 mm buccal and lingual, 0.5 mm proximal), cast dowel/core and crown; and 0 FRL, no ferrule, cast dowel/core and crown. The teeth were prepared to standardized specifications and stored for 72 hours in 100% humidity prior to testing. Testing was conducted with a universal testing machine with the application of a static load, and the load (N) at failure was recorded. Statistical analysis was performed with a 1-way analysis of variance and the Tukey Honestly Significant Difference test (α=.05). The mode of fracture was noted by visual inspection for all specimens. Results There was strong evidence of group differences in mean fracture strength ( P P =.0001) in mean fracture strength when compared with the uniform 2-mm vertical ferrule (2 FRL: 587.23 ± 110.25 N), the group without RCT (CRN: 583.67 ± 86.09 N), and the RCT-treated tooth with a crown alone (CRN/RCT: 571.04 ± 154.86 N). The predominant mode of failure was an oblique fracture extending from the lingual margin to the facial surface just below the insertion of the tooth into the acrylic resin. Conclusion The results demonstrated that central incisors restored with cast dowel/core and crowns with a 2-mm uniform ferrule were more fracture resistant compared to central incisors with nonuniform (0.5 to 2 mm) ferrule heights. Both the 2-mm ferrule and nonuniform ferrule groups were more fracture resistant than the group that lacked a ferrule.

Oral health–related quality of life in patients treated with fixed, removable, and complete dentures 1 month and 6 to 12 months after treatment

Abstract: Purpose This study described oral health–related quality of life (OHRQoL) before and after treatment in patients with fixed, removable, and complete dentures. Materials and Methods OHRQoL was measured using the German version of the Oral Health Impact Profile (OHIP-G) in a convenience sample of 107 prosthodontic patients at baseline and 1 and 6 to 12 months after treatment. The sum of OHIP-G item responses (OHIP-G49, range 0 to 196) characterized OHRQoL impairment in 42 patients treated with fixed prosthodontics, 31 patients treated with removable dentures, and 34 patients treated with complete dentures. OHIP-G49 medians were compared with the OHRQoL level in a general population sample (n = 2,026). A multivariable binomial regression analysis, controlling for the effects of baseline OHRQoL and follow-up wave, was used to compare the level of impaired OHRQoL in different prosthodontic treatment groups at follow-ups. Results OHRQoL improved in 96% of the subjects. OHIP-G49 medians reached the level of OHRQoL in the general population 1 month after treatment (fixed prosthodontics patients 6 OHIP-G units; general population subjects 5 units; removable denture patients 23 units, 15 units in general population subjects; complete denture patients 13 units, 23 units in general population subjects). OHIP-G49 medians were below population norms 6 to 12 months after treatment. In patients treated with removable/complete dentures, the expected posttreatment OHIP-G49 problem rate was 1.9 times the problem rate in patients treated with fixed prosthodontics, holding baseline OHIP-G49 and follow-up wave constant. Conclusion OHRQoL changed substantially comparing pretreatment scores with 1 and 6 to 12 months of follow-up in patients treated with fixed, removable, and complete dentures.—Reprinted with permission of Quintessence Publishing.

Long-term survival of endodontically treated molars without crown coverage: a retrospective cohort study.

Abstract: Statement of problem Teeth are weakened after endodontic treatment and should, ideally, be crowned, especially posterior teeth. However, this is not always possible. Information about the longevity of endodontically treated teeth without crown coverage may assist in selecting appropriate treatment modalities. Purpose The aims of this cohort study were to evaluate the survival rate for endodontically treated molars without crown coverage and to identify possible related factors. Material and methods A total of 220 endodontically treated permanent molar teeth in 203 subjects on a waiting list for fixed prosthodontic treatment at the Faculty of Dentistry-Mahidol University, Thailand, were included. Follow-up data were derived from a clinical examination and review of the dental record and radiographs. Subjects were not included in the study if teeth had provisional crowns, definitive restorations with cuspal coverage, or with dowel and core and/or crown restorations. The outcome evaluated was defined as a failure if there were negative findings in the condition of a tooth that required a restoration, tooth repair, or extraction. Tooth loss due to endodontic and periodontal reasons was excluded. The independent variables assessed were patient age, gender, location (maxilla or mandible), the existence of an opposing dentition and adjacent teeth, remaining tooth structure, and types of restorative material. Kaplan-Meier analysis with a 95% confidence level was used to calculate the survival probability, and a log-rank test was used to determine whether significant differences existed. Results Overall survival rates of endodontically treated molars without crowns at 1, 2, and 5 years were 96%, 88%, and 36%, respectively. With greater amounts of coronal tooth structure remaining, the survival probability increased. Molar teeth with maximum tooth structure remaining after endodontic treatment had a survival rate of 78% at 5 years. Restorations with direct composite had a better survival rate than conventional amalgam and reinforced zinc oxide and eugenol with polymethacrylate restorations. Conclusion Within the limitations of this study, the amount of remaining tooth structure and types of restorative material have significant association with the longevity of endodontically treated molars without crown coverage.

Immediate dentin sealing improves bond strength of indirect restorations.

Abstract: Statement of problem Delayed dentin sealing is traditionally performed with indirect restorations. With this technique, dentin is sealed after the provisional phase at the cementation appointment. It was demonstrated that this chronology does not provide optimal conditions for bonding procedures. Immediate dentin sealing (IDS) is a new approach in which dentin is sealed immediately following tooth preparation, before making the impression. Purpose The purpose of this study was to determine whether there were differences in microtensile bond strength to human dentin using IDS technique compared to delayed dentin sealing (DDS). Material and methods Fifteen freshly extracted human molars were obtained and divided into 3 groups of 5 teeth. A 3-step etch-and-rinse dentin bonding agent (DBA) (OptiBond FL) was used for all groups. The control (C) specimens were prepared using a direct immediate bonding technique. The DDS specimens were prepared using an indirect approach with DDS. Preparation of the IDS specimens also used an indirect approach with IDS immediately following preparation. All teeth were prepared for a nontrimming microtensile bond strength test. Specimens were stored in water for 24 hours. Eleven beams (0.9 × 0.9 × 11 mm) from each tooth were selected for testing. Bond strength data (MPa) were analyzed with a Kruskal-Wallis test, and post hoc comparison was done using the Mann-Whitney U test (α=.05). Specimens were also evaluated for mode of fracture using scanning electron microscope (SEM) analysis. Results The mean microtensile bond strengths of C and IDS groups were not statistically different from one another at 55.06 and 58.25 MPa, respectively. The bond strength for DDS specimens, at 11.58 MPa, was statistically different ( P =.0081) from the other 2 groups. Microscopic evaluation of failure modes indicated that most failures in the DDS group were interfacial, whereas failures in the C and IDS groups were both cohesive and interfacial. SEM analysis indicated that for C and IDS specimens, failure was mixed within the adhesive and cohesively failed dentin. For DDS specimens, failure was generally at the top of the hybrid layer in the adhesive. SEM analysis of intact slabs demonstrated a well-organized hybrid layer 3 to 5 μm thick for the C and IDS groups. For DDS specimens the hybrid layer presented a marked disruption with the overlying resin. Conclusions When preparing teeth for indirect bonded restorations, IDS with a 3-step etch-and-rinse filled DBA, prior to impression making, results in improved microtensile bond strength compared to DDS. This technique also eliminates any concerns regarding the film thickness of the dentin sealant.

The influence of ceramic surface treatments on the tensile bond strength of composite resin to all-ceramic coping materials

Abstract: Statement of problem An increasing demand for esthetic restorations has resulted in the development of new ceramic systems, but the fracture of veneering ceramics still remains the primary cause of failure. Porcelain repair frequently involves replacement with composite resin, but the bond strength between composite resin and all-ceramic coping materials has not been studied extensively. Purpose The purpose of this study was to evaluate the tensile bond strength of composite resin to 3 different all-ceramic coping materials with various surface treatments. Material and methods Thirty specimens (10 × 10 × 2 mm) each of lithium-disilicate ceramic (IPS Empress2 [E]), alumina ceramic (In-Ceram Alumina [I]), and zirconia ceramic (Zi-Ceram [Z]) were fabricated. Feldspathic ceramic (Duceram Plus [F]) was used as the control. Each material was divided into 3 groups (n=10), and 3 different surface treatments were performed: airborne-particle abrasion with 50-μm alumina particles (Ab); airborne-particle abrasion with 50-μm alumina particles and acid etching with 4% hydrofluoric acid (Ae); or airborne-particle abrasion with 30-μm alumina particles modified with silica acid (Si). After surface treatment of ceramic specimens, composite resin cylinders (5-mm diameter × 10-mm height) were light polymerized onto the ceramic specimens. Each specimen was subjected to a tensile load at a crosshead speed of 2 mm/min until fracture. The fracture sites were examined with scanning electron microscopy to determine the location of failure during debonding and to examine the surface treatment effects. Two-way analysis of variance and the Duncan multiple comparison test (α=.05) were used to analyze the bond strength values. Results There were significant differences in the bond strengths for both ceramics ( P P P FAb > (FSi, EAb, ESi) (IAb, IAe) > (ZAe, ZAb). The results illustrate no differences within the parentheses but statistically significant differences among the groups. Conclusion Alumina and zirconia ceramic specimens treated with a silica coating technique, and lithium disilicate ceramic specimens treated with airborne-particle abrasion and acid etching yielded the highest tensile bond strength values to a composite resin for the materials tested.

A 10-year randomized clinical trial on the influence of splinted and unsplinted oral implants retaining mandibular overdentures: Peri-implant outcome

Abstract: Purpose This randomized controlled clinical trial aimed to evaluate the efficacy of splinted implants versus unsplinted implants in overdenture therapy over a 10-year period. Materials and Methods The study sample comprised 36 completely edentulous patients, 17 men and 19 women (mean age 63.7 years). In each patient, 2 implants (Branemark System, Nobel Biocare, Goteborg, Sweden) were placed in the interforaminal area. Three to 5 months after placement, they were connected to standard abutments. The patients were then rehabilitated with ball-retained overdentures, magnet-retained overdentures, or bar-retained overdentures (the control group). Patients were followed for 4, 12, 60, and 120 months post–abutment connection. Group means as well as linear regression models were fitted with attachment type and time as classification variables and corrected for simultaneous testing (Tukey). Results After 10 years, 9 patients had died and 1 was severely ill. Over 10 years, no implants failed. Mean Plaque Index, Bleeding Index, change in attachment level, Periotest values, and marginal bone level at the end of the follow-up period were not significantly different among the groups. Discussion The annual marginal bone loss, excluding the first months of remodeling, was comparable with that found around healthy natural teeth. Conclusion The fact that no implants failed and that overall marginal bone loss after the first year of bone remodeling was limited suggested that implants in a 2-implant mandibular overdenture concept have an excellent prognosis in this patient population, irrespective of the attachment system used.— Reprinted with permission of Quintessence Publishing.

Treatment satisfaction with facial prostheses.

Abstract: Statement of problem Facial defects secondary to the treatment of neoplasms, congenital malformations, and trauma result in multiple functional and psychosocial difficulties. Prosthetic rehabilitation attempts to restore these facial disfigurements and may improve the level of function and self-esteem for these patients. However, a limited number of studies have evaluated the change in perceived quality of life after maxillofacial prosthetic rehabilitation. Purpose The purpose of this study was to evaluate patients' perceptions of treatment with adhesive-retained and implant-retained facial prostheses and to assess differences in overall satisfaction with these 2 types of treatments. Material and methods In this study, a questionnaire with 28 items was administered for evaluation of perceptions of appearance, comfort, fit and irritation, reliability of retention, frequency of wear, ease of placement and removal, level of self-consciousness, and value of treatment. Subjects were categorized into 2 groups: adhesive-retained group (n=16) and implant-retained group (n=19). Comparisons were made for each item in the questionnaire using Fisher exact tests (α=.05). Results The implant group reported higher positive ratings on all 28 questionnaire items when compared with the adhesive group. Statistically significant ( P Conclusion The implant-retained facial prosthesis offers significant enhancement over an adhesive-retained prosthesis with respect to ease of use and retention during a variety of daily activities, resulting in greater use of the prosthesis.

The effect of ceramic surface treatment on bonding to densely sintered alumina ceramic

Abstract: Universidade Federal de Santa Maria (UFSM), Sch Dent, Dept Restorat Dent, Rio Grande do Sul, Brazil

5-year follow-up of a prospective clinical study on various types of core restorations

Abstract: Purpose This study tested whether: (1) the survival rate of cast post-and-core restorations is better than the survival of direct post-and-core restorations and post-free all-composite cores; and (2) the survival of these buildup restorations is influenced by the remaining dentin height after preparation. Materials and Methods In a clinical trial, 18 operators made 319 core restorations in 249 patients. The restorations involved were: (1) cast post-and-core restorations; (2) direct post and composite core restorations; and (3) post-free all-composite cores. All restorations were made under single porcelain-fused-to-metal crowns. Treatments were allocated after dentin height assessment using balanced drawing. Failures were registered during a 5-year period. Results Fifteen restorations failed during the follow-up period. Five failures occurred during the first month; they were considered to be independent from clinical aging and excluded from further survival assessments. The overall survival was 96% ± 2%. No difference was found between the survivals of the different types of restorations. The factor “remaining dentin height” appeared to have a significant effect on the survival of post-and-core restorations (98% ± 2% survival for “substantial dentin height” vs 93% ± 3% for “minimal dentin height”). Conclusion The type of post and core was not relevant with respect to survival. The amount of remaining dentin height after preparation influenced the longevity of a post-and-core restoration.—Reprinted with permission of Quintessence Publishing.

Influence of firing cycles on the margin distortion of 3 all-ceramic crown systems.

Abstract: Statement of problem Although all-ceramic restorations are widely used, there is a lack of information about how the fit is affected by fabrication procedures. The adequacy of the fit of all-ceramic restorations has been questioned. Purpose This study examined the effect of porcelain and glaze firing cycles on the fit of 3 types of all-ceramic crowns. Material and methods Ten standardized all-ceramic crowns were fabricated on a metal die from each of 3 systems: conventional In-Ceram, copy-milled In-Ceram, and copy-milled feldspathic crowns. Copings of the conventional and copy-milled In-Ceram crowns and nonglazed copy-milled feldspathic crowns served as the control. A device was used to apply a uniform load on specimens during measurement and to reposition the specimens on the measurement device after each manufacturing process. The specimens were not cemented and were measured on the metal die using a profile projector. Measurements were recorded at 18 points selected along horizontal and vertical planes. The crown systems were compared by use of the Student t test and 1-way analysis of variance (ANOVA). Data of measurements repeated at identical locations were analyzed with a multivariate repeated-measures ANOVA. The Bonferroni post hoc test was used for multiple comparisons (α=.05). Results The conventional In-Ceram (57 ± 24 μ m) and copy-milled In-Ceram (57 ± 32 μ m) crowns demonstrated nearly identical marginal discrepancy values, followed by the copy-milled feldspathic crowns with a mean of 17 ± 12 μ m in the vertical plane. The copy-milled In-Ceram crowns had a mean horizontal discrepancy value of −12 ± 4 μ m, followed by the copy-milled feldspathic crowns with a mean of −4 ± 5 μ m and the conventional In-Ceram crowns with a mean of −6 ± 4 μ m. Statistical analyses demonstrated no significant differences in the marginal discrepancy values among the 3 all-ceramic crown systems, except for the horizontal discrepancy values between the conventional and copy-milled In-Ceram crowns after the porcelain firing cycle. Results indicated that the addition of porcelain to the copings caused a significant change ( P P Conclusions Within the limitations of this study, it was concluded that the 3 all-ceramic crown systems demonstrated a comparable and acceptable marginal fit. The porcelain firing cycle affected the marginal fit of the all-ceramic crowns. However, the glaze firing cycle had no significant effect on fit. The conventional and copy-milled In-Ceram crowns demonstrated medial deformations at the labial and palatal surfaces that might result in occlusal displacement of the crown.

Long-term treatment outcomes in edentulous patients with implant-fixed prostheses: the Toronto study.

Abstract: Purpose The aim of this prospective study was to report long-term treatment outcomes (prosthetic and implant related) of edentulous patients treated with implant-supported fixed prostheses who participated in the first clinical implant study in North America. Materials and methods Forty-five patients were treated with Branemark implants supporting a total of 47 fixed prostheses (42 mandibular and 5 maxillary) between 1979 and 1984. All patients were recalled regularly for comprehensive prospective clinical and radiographic assessments. Results Thirty-one patients (33 prostheses) attended a final recall visit in 2002; 71% of patients had been followed for 20 years (range 18 to 23 years), with overall prosthetic plan and implant outcome success rates of 84% and 87%, respectively. Mean marginal bone loss around the implants after the first year of loading was small (0.05 mm/year), with high individual variations. Poor oral hygiene, smoking history, and implant position appeared to be predictors of marginal bone loss. Prosthetic maintenance was ongoing and included fractured components and replacement of prostheses; the longevity of a fixed prosthesis for this group of patients was 8.39 ± 5.30 years. Conclusion This study confirmed the overall long-term treatment outcome success of patients treated with fixed prostheses supported by Branemark implants. Successful osseointegration with small mean bone loss was maintained as study patients aged, although prosthetic maintenance was required. The latter consideration should be discussed with all patients seeking such treatment.— Reprinted with permission of Quintessence Publishing.

Hardness of heat-polymerized acrylic resins after disinfection and long-term water immersion.

Abstract: Statement of the problem In selecting a disinfectant for dental prostheses, compatibility between the disinfectant and the type of denture base material must be considered to avoid adverse effects on the hardness of the acrylic resin. Purpose This study investigated the hardness of 2 denture base resins after disinfection and long-term water immersion. Material and methods Thirty-two disk-shaped specimens (13 mm in diameter and 8 mm thick) were fabricated from each resin (Lucitone 550 and QC-20), polished, stored in water at 37°C for 48 hours, and submitted to hardness tests (Vickers hardness number [VHN]) before disinfection. Disinfection methods included scrubbing with 4% chlorhexidine gluconate for 1 minute, immersion for 10 minutes in 1 of the tested disinfectant solutions (n=8) (3.78% sodium perborate, 4% chlorhexidine gluconate, or 1% sodium hypochorite), and immersion in water for 3 minutes. The disinfection procedures were repeated 4 times, and 12 hardness measurements were made on each specimen. Control specimens (not disinfected) were stored in water for 56 minutes. Hardness tests (VHN) were also performed after 15, 30, 60, 90, and 120 days of storage in water. Statistical analyses of data were conducted with a repeated measures 3-way analysis of variance (ANOVA) and Tukey post-hoc test (α=.05). Results Mean values ± SD for Lucitone 550 (16.52 ± 0.94 VHN) and QC-20 (9.61 ± 0.62 VHN) demonstrated a significant ( P P Conclusion Within the limitations of this in vitro study, QC-20 and Lucitone 550 specimens exhibited significantly lower hardness values after disinfection regardless of the disinfectant solution used.

Effects of polishing techniques on the surface roughness of acrylic denture base resins.

Abstract: Statement of problem Rough surfaces of denture bases promote adhesion of microorganisms and plaque formation. It is therefore important to know how different polishing systems affect surface roughness of denture base acrylic resins. Purpose The objective of this study was to compare the effects of 4 chairside polishing kits and 2 conventional laboratory techniques used for polishing 3 different acrylic denture base resins. Material and methods Using contact profilometric measurement, the surface texture of 54 specimens (15 × 30 × 3 mm) per acrylic material (autopolymerized ProBase Cold, heat-polymerized ProBase Hot, and injection heat-polymerized SR Ivocap plus) was studied before and after cutting with a tungsten carbide bur, and during and after chairside polishing with 4 polishing kits (Exa Technique, Acrylic Polisher HP blue, AcryPoint, Becht Polishing Cream), and after conventional polishing with 2 polishing systems (Universal Polishing Paste for Resins and Metals, Lesk Polishing Liquid). There were 9 specimens for each acrylic resin material and polishing method combination. Conventional lathe polishing with polishing paste served as the control. Mean average surface roughness (R a ) values of each specimen group were analyzed using a 2-way analysis of variance, the Scheffe post-hoc test, and paired t test (α=.05) with the Bonferroni adjustment. After testing the polished acrylic resin surfaces were evaluated under a scanning electron microscope. Results The highest mean average surface roughness (R a =2.86 ± 0.8 μm to 3.99 ± 1.31 μm) was measured for surfaces finished with a tungsten carbide bur. The lowest surface roughness values (R a =0.02 ± 0.01 μm) were determined for acrylic resin specimens polished with a lathe and polishing paste. The R a values of resin specimens after polishing with chairside silicone polishing kits ranged from 0.05 ± 0.0 μm to 0.35 ± 0.05 μm. Mean average R a values of specimens polished with a polishing cream alone (R a =1.01 ± 0.17 μm to 1.68 ± 0.47 μm) were significantly higher ( P Conclusions Conventional laboratory polishing was found to produce the smoothest surface of denture base acrylic resin. Chairside silicone polishing kits produced a significantly smoother surface of acrylic resin than specimens polished with a tungsten carbide bur. The presence of large pores was characteristic for the autopolymerizing resin material.

Clinical case reports of injectable tissue-engineered bone for alveolar augmentation with simultaneous implant placement

Abstract: This clinical study was undertaken to evaluate the use of tissue-engineered bone, mesenchymal stem cells, platelet-rich plasma, and beta-tricalcium phosphate as grafting materials for maxillary sinus floor augmentation or onlay plasty with simultaneous implant placement in six patients with 3- to 5-mm alveolar crestal bone height. All 20 implants were clinically stable at second-stage surgery and 12 months postloading. A mean increase in mineralized tissue height of 7.3 ± 4.6 mm was evident when comparing the pre- and postsurgical radiographs. Injectable tissue-engineered bone provided stable and predictable results in terms of implant success.— Reprinted with permission of Quintessence Publishing.

Longevity and failure load of ceramic veneers with different preparation designs after exposure to masticatory simulation.

Abstract: Statement of problem Laminate veneers are widely used in the management of unesthetic anterior teeth. However, limited information is available regarding the influence of preparation design on longevity of ceramic veneers. Purpose This study evaluated the influence of preparation design on longevity and failure load of ceramic veneers bonded to human maxillary central incisors after cyclic loading and thermal cycling in a dual-axis masticatory simulator. Material and methods Sixty-four caries-free maxillary central incisors were divided into 4 groups (n=16). The control group remained unprepared (NP). For Group WP, a window preparation was made. Specimens in Group IOP were prepared with an incisal overlap of 2 mm without palatal chamfer. For Group CVP, specimens were prepared with a complete-veneer design of 3-mm incisal reduction and 2-mm palatal extension. Forty-eight IPS Empress 1 ceramic veneers were bonded adhesively with dual-polymerizing composite (Variolink II). All specimens were subjected to cyclic mechanical loading (1.2 million cycles, cycle frequency 1.3 Hz, invariable palatal load 49 N) and thermal cycling (5°C-55°C, dwell time 60 seconds, 5500 cycles) in a masticatory simulator. Failure was defined by bulk fracture of a specimen. Subcritical crack patterns were observed. Surviving specimens were loaded in a universal testing machine until fracture. The failure-load values (N) (1.5 mm/min crosshead speed) were automatically recorded by controlling software. Statistical analysis of data was performed by Kruskal-Wallis analysis of variance (α=.05) and pairwise Wilcoxon rank sum tests (α=.05). Results Three specimens from group NP, 1 specimen each from the WP and CVP groups, and 2 specimens from group IOP fractured during fatigue. After 1.2 million cycles, the highest crack rates were observed for complete veneers and originated in the palatal concavity extending to the facial surface. The median (interquartile range=x .25 -x .75 ) failure loads (N) were as follows: NP 713.3 (404.4-777.1), WP 549.5 (477.5-597.7), IOP 695.3 (400.0-804.6), and CVP 519.2 (406.1-732.9). No significant differences in longevity and failure load were demonstrated between natural teeth and teeth restored with ceramic veneers ( P =.555). Conclusion Maxillary teeth restored with the 3 types of IPS Empress 1 veneers showed fracture resistance similar to that of unprepared incisors ( P =.555).

The prosthodontic concept of crown-to-root ratio: A review of the literature

Abstract: Crown-to-root ratio is intended to serve as an aid in predicting the prognosis of teeth. However, controversy persists as to its impact on diagnosis and treatment planning. This article critically reviews the available literature on the crown-to-root ratio assessment and criteria for evaluation of abutment use of periodontally compromised teeth. A Medline search was completed for the time period from 1966 to 2003, along with a manual search, to locate relevant peer-reviewed articles and textbooks published in English. Key words used were "crown-to-root ratio," "periodontal compromised dentition," "mobility," and "biomechanics." There was a dearth of evidence-based research on the topic. Although the use of the crown-to-root ratio in addition to other clinical indices may offer the best clinical predictors, no definitive recommendations could be ascertained.

Three-dimensional finite-element analysis of functional stresses in different bone locations produced by implants placed in the maxillary posterior region of the sinus floor

Abstract: Statement of problem Implants placed in the posterior maxilla have lower success rates compared to implants placed in other oral regions. Inadequate bone levels have been suggested as a reason for this differential success rate. Purpose The purpose of this study was to determine the amount and localization of functional stresses in implants and adjacent bone locations when the implants were placed in the posterior maxilla in proximity to the sinus using finite element analysis (FEA). Material and methods A 3-dimensional finite element model of a maxillary posterior section of bone (Type 3) was used in this study. Different bony dimensions were generated to perform nonlinear calculations. A single-piece 4.1 × 10–mm screw-shaped dental implant system (ITI solid implant) was modeled and inserted into atrophic maxillary models with crestal bone heights of 4, 5, 7, 10, or 13 mm. In some models the implant penetrated the sinus floor. Cobalt-Chromium (Wiron 99) was used as the crown framework material placed onto the implant, and porcelain was used for occlusal surface of the crown. A total average occlusal force (vertical load) of 300 N was applied at the palatal cusp (150 N) and mesial fossa (150 N) of the crown. The implant and superstructure were simulated in finite element software (Pro/Engineer 2000i program). Results For the porcelain superstructure for bone levels, maximum von Mises stress values were observed on the mesial fossae and palatal cusp. For the bone structure, the maximum von Mises stress values were observed in the palatal cortical bone adjacent to the implant neck. There was no stress within the spongy bone. High stresses occurred within the implants for all bone levels. Conclusion The maximum von Mises stresses in the implants were localized in the neck of implants for 4- and 5-mm bone levels, but for 7-, 10-, and 13-mm bone levels more even stresses occurred within the implants.

Smoking and complications of onlay bone grafts and sinus lift operations

Abstract: Purpose To compare the incidence of complications related to onlay bone grafts (OBGs) and sinus lift operations (SLOs) among smokers and nonsmokers. Materials and methods Data from 143 operations performed during the years 1995 to 2003 were analyzed. There were 64 OBGs and 79 SLOs. Patients were divided into 3 groups: nonsmokers, mild smokers (up to 10 cigarettes per day), and heavy smokers (more than 10 cigarettes per day). Duration of smoking (less or more than 10 years) was recorded. OBG complications were classified as minor (hematoma, swelling, inflammation, or temporary paresthesia) or major (graft exposure or mobility). For the SLO, perforations of the schneiderian membrane were the main intraoperative complication; postoperative complications mostly consisted of swelling, acute or chronic sinus infection, or bleeding. Results Of smokers having OBG, 50% experienced complications, compared to 23.1% of nonsmokers. Major complications were observed in one third of the smokers, compared to only 7.7% in nonsmokers. There was also a tendency toward complications in former smokers, although this relationship was not statistically significant. There was no relationship between SLO complications and smoking or a past smoking habit. Discussion In the present study, smokers demonstrated significantly higher postoperative complications following OBG operations. Smoking did not influence the results in the SLO group. There was no statistically significant difference between complications and past smoking. This finding indicates that the risk of complications can be reduced up to the normal nonsmoker complication rate when smoking ceases. Conclusions This study established a relationship between OBG complications and smoking in this patient population. A higher incidence of complications was found in the smoking group. There was no significant influence of smoking on SLO complications.— Reprinted with permission of Quintessence Publishing.

Self-etch vs etch-and-rinse adhesives: effect of thermo-mechanical fatigue loading on marginal quality of bonded resin composite restorations

Abstract: Objective This study evaluated the marginal integrity of dentine adhesives bonded to enamel and dentine, before and after thermo-mechanical loading (TML). Methods MO cavities with proximal boxes beneath the CEJ were prepared in extracted human third molars. Direct resin composite restorations (Tetric Ceram) were bonded with 3-step etch-and-rinse (Syntac Classic, Solobond Plus, OptiBond FL), 2-step etch-and-rinse (Admira Bond, Single Bond), 2-step self-etch (AdheSE, Clearfil SE Bond), and 1-step self-etch (all-in-one) adhesives (Adper Prompt, Xeno III, iBond). Marginal gaps were analyzed using SEM of epoxy resin replicas. Bonded interfaces before TML were examined with TEM to identify pre-existing attributes for subsequent marginal disintegration. Results In enamel, high percentages of gap-free margins were initially identified for all adhesives. After TML, etch-and-rinse adhesives exhibited significantly higher percentages of gap-free margins (approximately 90%) compared with two-step self-etch (approximately 75%) and all-in-one (approximately 55%) adhesives ( p p >.05). The all-in-one adhesives exhibited significantly less gap-free margins ( p Conclusion Enamel bonding was more effective with phosphoric acid-etching. Etch-and-rinse and 2-step self-etch adhesives showed promising marginal adaptation to dentine and may have a better clinical prognosis than the all-in-one bonding approach.— Reprinted with permission of The Academy of Dental Materials.

Long-term treatment outcomes in edentulous patients with implant overdentures: the Toronto study.

Abstract: Purpose Few long-term studies on overdentures report both implant and prosthodontic outcomes. The aim of this prospective study was to report long-term prosthodontic- and implant-related treatment outcomes of patients treated with design-specific implant-supported overdentures. Materials and methods Between 1982 and 1992, 45 consecutively treated patients received a total of 47 overdentures (42 mandibular and maxillary) supported by Branemark implants. Prospective clinical and radiographic data were collected over the observation period; this study presents the most recent treatment outcomes. Results Thirty patients (mean age 70 years) with 32 prostheses attended the final recall visit, with 67% of patients followed for 15.53 years (range 10 to 19 years). Six implants failed, and the prosthetic plan and implant cumulative survival rates were both in excess of 90%. Mean marginal bone loss around implants after the first year of loading was small (0.05 mm/year), although the individual variation was high. Linear regression analysis of bone loss indicated that gender, bicortical stabilization, bone quality, and healing time were predictors of bone loss for the first year of loading but not for the ensuing years. Prosthetic maintenance included fractured components, denture relining, and replacement of prostheses. On average, the longevity of overdenture prostheses was 12 years, and laboratory relining was necessary every 4 years. Conclusion This study confirmed the long-term outcome success of patients treated with design-specific overdenture prostheses supported by Branemark implants. However, prosthetic maintenance was required, a fact that should be discussed with patients prior to treatment.—Reprinted with permission of Quintessence Publishing.