Showing papers in "International Journal of Prosthodontics in 2008"

Clinical behavior of zirconia-based fixed partial dentures made of DC-Zirkon: 3-year results.

Abstract: PURPOSE The aim of this prospective study was to evaluate the clinical performance of anterior and posterior fixed partial dentures (FPDs) with frameworks made using DC-Zirkon after a mean observation time of 3 years. MATERIALS AND METHODS Forty-six patients with 1 to 3 missing anterior or posterior teeth were included in this study. All abutment teeth were prepared for full crowns with a chamfer preparation of 0.6 to 0.8 mm. The zirconia frameworks were produced with the Precident DCS system and veneered with veneering porcelain (Vita D). A self-curing resin cement was used for the anterior FPDs and a conventional zinc oxide phosphate cement was used for the posterior FPDs. RESULTS Fifteen anterior FPDs and 50 posterior FPDs were recalled at least once a year after cementation. The mean observation period was 38 (+/- 18.0) months for the anterior FPDs and 37 (+/- 15.5) months for the posterior FPDs. Within the observation time, no remakes were necessary, but in 4 cases a small chipping of the veneering material occurred in the posterior region. Two FPDs were recemented after decementation, and 3 teeth needed endodontic treatment. No negative influences at the gingival margin were observed. CONCLUSIONS Within the mean observation time of 3 years, zirconia-based FPDs demonstrated a sufficient success rate under clinical conditions. However, special attention should be paid to designing the zirconia framework to ensure a sufficient veneering layer thickness with a range between 1 to 2 mm.

Five-year clinical prospective evaluation of zirconia-based Denzir 3-unit FPDs

Abstract: Purpose: The aim of this prospective study was to evaluate the clinical performance of fully sintered hot isostatic pressed yttria-partially-stabilized zirconia (Denzir) 3-unit fixed partial dentur ...

Clinical studies of fiber posts: a literature review.

Abstract: Purpose This literature review aimed to find answers to relevant questions regarding the clinical outcome of endontically treated teeth restored with fiber posts. Materials and methods All clinical studies published since 1990 in journals indexed in MEDLINE were retrieved by searching PubMed with the query terms "fiber posts and clinical studies." The reference list of the collected articles was also screened for further relevant citations. The strength of the evidence provided by the reviewed papers was assessed according to the criteria of evidence-based dentistry. Results Five randomized controlled trials (RCTs) on fiber posts have been published in peer-reviewed journals. A meta-analysis is not applicable to these studies since they do not address the same specific clinical question. Retrospective and prospective trials without controls are also available. Conclusions Two RCTs indicate that fiber-reinforced composite posts outperform metal posts in the restoration of endontically treated teeth. However, this evidence cannot be considered as conclusive. Longer-term RCTs would be desirable. The placement of a fiber-reinforced composite post protects against failure, especially under conditions of extensive coronal destruction. The most common type of failure with fiber-reinforced composite posts is debonding.

Osseointegration and clinical success of zirconia dental implants: a systematic review.

Abstract: Purpose: Various ceramic implant systems made of yttria‐stabilized tetragonal zirconia polycrystals (Y-TZP) have become commercially available in recent years. A systematic search of the literature was performed to assess the clinical success of dental Y-TZP implants and whether the osseointegration of Y-TZP is comparable to that of titanium, the standard implant material. Materials and Methods: The internet database MEDPILOT was searched cumulatively for the keywords zircon* and dent* and implant as well as for zircon* and osseointegration. The last search was conducted on January 31st, 2007. Subsequently, the reference lists of the relevant publications were searched. Furthermore, a letter was sent to the 5 identified manufacturers of zirconia dental implants to ask for peer-reviewed publications. Results: Ninety-six articles were found by the search strategy. No controlled clinical studies in humans regarding clinical outcomes or osseointegration could be identified. Clinical data were restricted to case studies and case series. Only 7 animal studies fulfilled the inclusion criteria. Osseointegration was evaluated at 4 weeks to 24 months after placement in different animal models and sites and under different loading conditions. The mean bone-implant contact percentage was above 60% in almost all experimental groups. In studies that used titanium implants as a control, Y-TZP implants were comparable to or even better than titanium implants. Surface modifications may further improve initial bone healing and resistance to removal torque. Conclusions: Y-TZP implants may have the potential to become an alternative to titanium implants but cannot currently be recommended for routine clinical use, as no long-term clinical data are available. Int J Prosthodont 2008;21:27‐36.

Single implants in the anterior maxilla after 15 years of follow-up: comparison with central implants in the edentulous maxilla.

Abstract: PURPOSE To present long-term clinical and radiographic data on single-implant treatment in the anterior maxilla and to compare these results with comparable data of central implants supporting fixed prostheses in the edentulous maxilla. MATERIALS AND METHODS A total of 38 patients consecutively restored with 47 single-implant crowns in the anterior maxilla were included in the single-implant (study) group. The implants in the edentulous group (control) were included by randomly selecting one of the central implants (closest to midline) from 76 consecutively treated edentulous patients. Mean age was 25.4 years (SD: 10.0) and 60.1 years (SD: 11.6) at inclusion (P .05) or between study and control implants after 15 years (P > .05). CONCLUSIONS There is an obvious difference between the survival of the implants (100%) and original implant crowns (77%) in the study group. The present early single-implant restorations showed significantly more mechanical/fistula problems compared to central implants in the edentulous maxilla (P < .05), but bone response was similar for both groups during 15 years of follow-up. Bone loss was not affected by the level of the implant head in relation to the cementoenamel junction of adjacent teeth, nor was it affected by mechanical or mucosal problems or persistent fistulas of the single implants during the entire follow-up period.

Quantitative measurement of tooth and ceramic wear: in vivo study.

Abstract: Purpose: The aim of this study was to quantitatively measure tooth and ceramic wear over a 2-year period using a novel superimposition technique. Three ceramic systems—experimental hot-pressed ceramic (EC), Procera AllCeram (PA), and metalceramic—were used. Materials and Methods: A total of 90 posterior crowns in 48 patients were randomized into 3 groups, and impressions were made at baseline and at 6-month intervals for 2 years. Clinical images were taken after using a dye to highlight surface changes. The impressions were digitized and modeled as superimposable 3-dimensional colored surface images. The depth of wear at the occlusal contact areas was quantitatively measured at 6, 12, 18, and 24 months. Results: The quantitative evaluation showed more wear in Procera AllCeram at the occlusal contact areas, whereas the experimental and metal-ceramic systems showed less wear. There was a significant difference in the amount of enamel worn between all types of restorations (P < .05). There was a statistically significant difference (P < .05) in the mean depth of wear between all systems. Conclusions: The metalceramic and experimental systems showed less change, indicating improved wear resistance compared with Procera AllCeram. In addition, enamel opposing metalceramic and experimental crowns showed less wear compared to enamel opposed by Procera AllCeram crowns. Int J Prosthodont 2008;21:245‐252.

Long-term clinical results of chairside Cerec CAD/CAM inlays and onlays: a case series.

Abstract: PURPOSE: The objective of this follow-up study was to examine the performance of Cerec inlays and onlays, all of which were placed by the same clinician, in terms of clinical quality over a functional period of 15 years. MATERIALS AND METHODS: Of 200 Cerec inlays and onlays placed consecutively in a private practice by one of the authors (TO) between 1989 and early 1991, 187 were closely monitored over a period of 15 years. All ceramic inlays and onlays had been placed chairside using the Cerec 1 method and had been luted with a bonding composite. Up to 17 years after their placement, a follow-up assessment was conducted, and the restorations were classified using modified United States Public Health Service criteria. RESULTS: According to Kaplan-Meier analysis, the success rate of Cerec inlays and onlays was 88.7% after 17 years. A total of 21 failures (11%) were found in 17 patients. Of these failures, 76% were attributed to ceramic fractures (62%) or tooth fractures (14%). The reasons for the remaining failures were caries (19%) and endodontic problems (5%). Restorations of premolars presented a lower failure risk than those of molars. CONCLUSION: The survival rate probability of 88.7% after up to 17 years of clinical service for Cerec computer-aided design/computer-assisted machining restorations made of Vita Mk I feldspathic ceramic is regarded as a very respectable clinical outcome.

Twenty-Year Follow-up of Metal-Ceramic Single Crowns: A Retrospective Study

Abstract: Purpose The aim of this clinical retrospective study was to evaluate the survival and success of single metal-ceramic crowns after 20 years. The biologic and technical complications as well as patient satisfaction were recorded. Materials and methods Fifty patients treated with 100 single metal-ceramic crowns attended the clinical 20-year follow-up examination. The mean follow-up time was 18.8 years (17.5 to 20.5 years). Results Twenty-one teeth with single crowns were extracted because of root fractures or esthetic or periodontal reasons. Ninety-seven percent of the subjects had no complaints about the esthetics of the crowns. The most common clinical findings were supragingival crown margins caused by gingival recessions, gingival bleeding on probing, and occlusal wear in opposing teeth. The success of the crowns after 20 years was 75%, and the survival was 78%. Conclusion In the 20-year follow-up of single metal-ceramic crowns, there were few biologic and technical complications, and patients were satisfied with the crowns. Crown removal was in most cases the result of root fractures in single crowns with endodontic posts.

An analysis of the persistent presence of opportunistic pathogens on patient-derived dental impressions and gypsum casts.

Abstract: PURPOSE: This study aimed to assess the persistent presence of microorganisms on patient-derived dental impressions and gypsum casts, while highlighting important human pathogens such as Candida, methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa. MATERIALS AND METHODS: The practices and opinions regarding cross-infection control from 59 general dentists in Japan were obtained via a questionnaire. Alginate impressions were made from 56 patients. Using a brain heart infusion agar medium, impression and imprint cultures were carried out to visualize the microbial contamination on the surfaces of the impressions and gypsum casts, respectively. The colonies on the surfaces of the 30 impression cultures and 26 imprint cultures were collected by swabbing and then inoculated onto selective agar plates to detect streptococci, staphylococci, Candida, MRSA, and P aeruginosa. RESULTS: The questionnaire showed that only 54% of general dentists had a cross-infection policy in their dental clinics, and only 30% to 40% were aware of the possible persistence of MRSA or P aeruginosa on impressions and gypsum casts. The impression/imprint cultures grew a large number of visible bacterial colonies on all of impression/gypsum cast samples investigated. Selective agar cultures demonstrated the presence of streptococci (100, 100%), staphylococci (56.7, 65.4%), Candida (30, 46.2%), MRSA (26.7, 15.4%), and P aeruginosa (6.7, 7.7%) on the impressions and the gypsum casts, respectively. CONCLUSIONS: This investigation showed that patient-derived dental impressions and gypsum casts are contaminated with numerous microbes, including Candida, MRSA, and P aeruginosa, which are known pathogens responsible for nosocomial and/or life-threatening infection in the immunocompromised host.

The immediately loaded single implant-retained mandibular overdenture: a 36-month prospective study.

Abstract: Purpose The aim of this study was to ascertain whether simplifying mandibular overdenture treatment by using single-stage surgery and immediate prosthetic loading of a single implant will achieve acceptable implant success rates, functional improvement, and increased patient satisfaction. As part of this study, the Mk III Branemark implant with an oxidized surface was compared to the classic machined Mk III Branemark implant. Materials and methods Thirty-five patients (mean age: 68 years) with problematic mandibular dentures were treated. The primary complaints among the patients referred to the clinic for treatment were poor retention of the mandibular denture, instability, denture sores, and phonetic problems. Initially, patients were placed randomly into the "machined surface" or "oxidized surface" groups. A single implant was placed in the mandibular midline with high initial stability. A ball attachment was placed and the retentive cap incorporated into the existing denture. Reviews took place at 3, 12, and 36 months posttreatment. Clinical assessments, radiographs made with custom film holders, and stability measurements by both manual and resonance frequency analysis methods were recorded. All complications, failures, maintenance, and reasons for dropout were noted. Visual analog scale questionnaires were used to record patient satisfaction (analysis of variance: P Results Three of eight machined-surface implants failed, representing an unacceptably high failure rate (37.5%). The machined surface was therefore discontinued for this study. One machined and two oxidized-surface implants did not achieve sufficient primary stability to be immediately loaded, so they were treated with a two-stage delayed loading protocol. The 25 immediately loaded oxidized-surface implants were all classified as surviving at the 36-month recall. Patient satisfaction was very high with a significant increase in all comfort and functional parameters. Conclusions Within the limitations of this study and research design, it appears that over a 3-year observation period, the immediately loaded single implant-retained mandibular overdenture, using an oxidized-surface implant and the existing prosthesis in a small group of prosthetically maladaptive patients, can provide a beneficial treatment outcome with a minimal financial outlay. Int J Prosthodont 2010;23:13-21.

Three-dimensional finite element analysis of load transmission using different implant inclinations and cantilever lengths.

Abstract: Many clinical studies have reported high survival rates for tilted implants. However, tilted implants transmit increased stress to bone when compared to vertically placed implants. Theoretical (computer-based), laboratory, and clinical studies are warranted to effectively address this issue. In this study, a 3-dimensional finite element analysis was performed to analyze the stress values surrounding tilted versus vertical implants. The results revealed laboratory and biomechanical evidence that distal tilting of implants, splinted in full fixed prostheses without cantilevers, reduced the amount of stress generated around the peri-implant bone when compared to the levels of stress seen in peri-implant bone with vertical implants and cantilevered segments in similar full fixed prostheses.

A review of functional outcomes related to prosthetic treatment after maxillary and mandibular reconstruction in patients with head and neck cancer.

Abstract: Purpose This review examined literature that reported functional outcomes across 3 categories of prosthetic treatment after microvascular reconstruction of the maxilla and mandible: (1) conventional dental/tissue-supported prosthesis, (2) implant-retained prosthesis, and (3) no prosthesis. Materials and methods Library databases were searched for articles related to reconstruction of the maxilla and mandible, and references of selected articles were hand searched. Relevant literature was identified and reviewed with criteria specified a priori. Results Forty-nine articles met the inclusion criteria. Twelve articles reported on function after maxillary reconstruction, with the majority of articles reporting on outcomes for 1 to 6 subjects. Thirty-nine articles reported on function after mandibular reconstruction. Speech outcomes were satisfactory across all groups. Swallowing reports indicated that many patients who received either type of prosthetic rehabilitation resumed a normal diet, whereas those without prosthetic rehabilitation were often restricted to liquid diets or feeding tubes. Patients without prosthetic rehabilitation reportedly had poor masticatory ability, whereas conventional prosthetic treatment allowed some recovery of mastication and implant-retained prosthetic treatment resulted in the most favorable masticatory outcomes. Quality-of-life outcomes were similar across all patients. Conclusions Several limitations of the current literature prevented definitive conclusions from being reached within this review, especially regarding maxillary reconstruction. However, recognition of these limitations can direct functional assessment for the future.

The influence of interimplant distance and attachment type on the retention characteristics of mandibular overdentures on 2 implants: 6-month fatigue retention values.

Abstract: This in vitro study evaluated the 6-month fatigue retention provided by 5 paired overdenture attachments placed at 3 different interimplant distances (19, 23, and 29 mm). Mean fatigue retention was calculated for each attachment type and compared with the retention produced by the other attachments tested and the initial retention values published earlier. Interimplant distance was found to play a significant role only in the retention of the Hader bar with red and yellow clips. A significant reduction in retention values was observed for 4 of 5 attachment types.

Factors related to patients' general satisfaction with removable partial dentures: a stepwise multiple regression analysis.

Abstract: This study aimed to analyze factors related to patients' general satisfaction with removable partial dentures (RPDs), such as esthetics, retention, speech, chewing, and comfort. A total of 103 patients with Kennedy Class I RPDs (34 to 82 years old; mean age: 63; 35 men, 68 women) assessed their satisfaction with dentures. Stepwise multiple regression analysis was used to evaluate the relationship among the factors. Significant correlations were found between general satisfaction and each of the individual components (P < .05). The patients' assessment of esthetics explained almost 50% of general satisfaction in both arches (P < .05). Esthetics, chewing, and speech had significant effects on the patients' general satisfaction with dentures.

Changes in attitudes toward desire for implant treatment: a longitudinal study of a middle-aged and older Swedish population.

Abstract: Purpose To assess, at a 10-year interval, changes in attitudes toward desire for implant treatment among middle-aged and older Swedish subjects with respect to dental status. Materials and methods Three thousand subjects, residents of Orebro County, Sweden, were surveyed via the same questionnaire in 1989 and again in 1999 regarding their possible need for and interest in implant-based prosthodontic treatment. Results One thousand six hundred sixty-five subjects responded to both surveys. In 1989 few respondents indicated an interest in implant treatment, whereas in 1999, 92% of those who had not indicated an interest in the earlier survey now indicated that they desired implant treatment. The cohort reporting having no teeth had a considerable lower increase in desire. Among those who reported a possible treatment need (ie, missing 1 or more teeth and had not had them replaced or those who wore complete dentures), cost was the most commonly cited reason for declining implant treatment. Conclusions There was a dramatic increase in the interest for implant treatment over the period from 1989 to 1999. Changes in awareness of implant treatment, along with an expansion in the number of qualified providers, may have contributed to this increase.

Effect of removable partial dentures on oral health-related quality of life in subjects with shortened dental arches: a 2-center cross-sectional study.

Abstract: PURPOSE: To assess the value of removable partial dentures (RPDs) in subjects with shortened dental arches (SDAs) with regard to quality of life. MATERIALS AND METHODS: Subjects from 2 university dental centers (82 men, 78 women; mean age: 54 +/- 18 years) were categorized into the following groups: (1) SDA with intact anterior regions (SDA-1, n = 44); (2) SDA and interrupted anterior region (SDA-2, n = 21); (3) SDA (intact anterior region) extended with distal-extension RPD (RPD-1, n = 25); (4) subjects with interrupted SDA and interrupted anterior region treated with RPD (RPD-2, n = 32); or (5) complete dental arches (CDA, n = 38) as a control. All subjects underwent a short clinical examination and completed 2 structured questionnaires: the Oral Health Impact Profile (OHIP-49) and the Short-Form Health Survey (SF-36). Recorded clinical variables included: teeth present (yes/no), replacement by RPD (yes/no), and number of occlusal units. Age-dependent outcomes were adjusted to outcomes for the age of 60 years. Linear regression models were used to assess differences between the groups. RESULTS: Reliability and validity were good for all subscales. For OHIP, the investigation groups had significantly higher scores (more complaints) than CDA for the subscales "functional limitation," "psychologic discomfort," and "physical disability." Of the 4 investigation groups, SDA-1 subjects had the lowest mean scores. SF-36 scores showed less prominent and less conclusive differences between investigation groups and CDA subjects. SDA-2 subjects showed worse health, with significantly lower scores than RPD-2 subjects for "vitality," "social function," and "mental health." For pure SDA subjects (SDA-1) there was a significant positive effect for "number of occlusal units" in 5 of the OHIP subscales and 2 of the SF-36 subscales. CONCLUSION: From a quality-of-life perspective, patients with SDAs perceive benefits from RPDs only if anterior teeth replacements are included. In contrast, in subjects with uninterrupted SDAs, where only posterior teeth were replaced by distal-extension RPDs, such benefits could not be demonstrated.

The influence of bar design (round versus milled bar) on prosthodontic maintenance of mandibular overdentures supported by 4 implants: a 5-year prospective study.

Abstract: PURPOSE The aim of the present study was to evaluate the prosthodontic maintenance required for mandibular overdentures supported by 4 implants and splinted with either a round bar and resilient overdenture anchorage or a milled bar with rigid anchorage over a 5-year period. MATERIALS AND METHODS In a randomized prospective trial, 51 edentulous patients received 4 mandibular interforaminal implants to support an overdenture and maxillary complete dentures. For the implant-supported overdentures (IODs), bar architecture and denture stabilization were chosen randomly; 25 patients received round bars (group 1) and resilient anchorage and 26 patients received milled bars (group 2) and rigid anchorage. The prosthodontic maintenance required for the IODs and opposing dentures were evaluated during a 5-year follow-up period and compared between the 2 retention modalities used for IODs. RESULTS Forty-six patients (22 in group 1, 24 in group 2) were available for a 5-year follow-up (dropout rate: 9.8%). Prosthodontic maintenance efforts were significantly greater (P < .01) with the round bar design (group 1) than with the overdentures stabilized with milled bars (group 2). In group 1, prosthodontic maintenance efforts were more frequent in the early phase of use (1 to 2 years), as compared with an evenly distributed incidence over the 5-year period with the rigid milled bar system. Major prosthetic complications (IOD remaking, bar fracture) were only seen in cases without metal-reinforced frameworks (group 1). CONCLUSION When 4 interforaminal implants are used to anchor mandibular overdentures, the design of the anchorage system will significantly affect prosthodontic maintenance efforts and complication rates. Rigid anchorage using milled bars and a metal-reinforced denture framework required less prosthodontic maintenance, ie, for clip activation/fracture, than resilient denture stabilization using multiple round bars without a rigid denture framework.

Effect of veneering method on the fracture and bond strength of bilayered zirconia restorations.

Abstract: This study evaluated the fracture strength and microtensile bond strength of a new computer-aided design (CAD) veneering method for zirconia frameworks. A new CAD/computer-assisted manufacture system was used to fabricate a resin replica of the esthetic ceramic required to veneer a zirconia framework. The replicas were processed using press-on technology. Identical manually layered zirconia specimens served as a control (n = 18; alpha = .05). Statistical analysis revealed that the fracture strength (442.8 +/- 25 N) and microtensile bond strength (26.6 +/- 2 MPa) of CAD-veneered zirconia were significantly higher (P < .001) compared to the control (346 +/- 24 N and 15.1 +/- 1 MPa, respectively). CAD veneering is a reliable method for veneering zirconia frameworks.

The relationship between missing occlusal units and oral health-related quality of life in patients with shortened dental arches.

Abstract: This study aimed to investigate the relationship between missing occlusal units and oral health-related quality of life (OHRQoL) in subjects with shortened dental arches (SDAs) Subjects with SDAs (N = 115) were recruited consecutively from 6 university-based prosthodontic clinics OHRQoL was measured using the Japanese version of the Oral Health Impact Profile (OHIP-J) An increase of 1 missing occlusal unit was associated with an increase of 21 OHIP-J units (95% CI: 06-35, P = 02) in a linear regression analysis Missing occlusal units are related to OHRQoL impairment in subjects with SDAs

Marginal fit of Zirconia posterior fixed partial dentures.

Abstract: The aim of this study was to investigate the marginal fit of posterior fixed partial dentures (FPDs) made with 2 computer-aided design/computer-assisted manufacture systems--Procera Bridge Zirconia (Nobel Biocare) and Lava AllCeramic System (3M ESPE)--and to analyze the differences between abutments and between buccal and lingual surfaces. Twenty standardized specimens were prepared to receive posterior 3-unit FPDs. FPDs were fabricated according to the manufacturer's instructions. A scanning microscope (JSM-6400, JEOL) with a magnification of 1,000x was used for measurements. Three-way analysis of variance showed significant differences (P < .001) in marginal adaptation between the ceramic groups. Procera Bridge Zirconia showed the lowest discrepancies (26 +/- 19 microm). No significant differences were observed between abutments and surfaces, and no significant interaction was observed among the ceramic system, abutments, and surfaces. The accuracy of fit achieved by both zirconia systems was within the range of clinical acceptability, with Procera Bridge Zirconia showing the best marginal fit.

Survival and complication rates of combined tooth-implant-supported fixed and removable partial dentures.

Abstract: Purpose The aim of this study was to assess and compare clinical outcome results of tooth-implant-supported fixed and removable partial dentures in a selected population group of partially edentulous patients. Biological and technical complications were recorded and reviewed. Materials and methods A retrospective analysis of the dental charts of 224 patients (174 men, 50 women) with a mean age of 51.3 years was carried out. The evaluation included details regarding the survival and technical complications of the prescribed prostheses, as well as the biological and technical complications associated with both types of abutments used, ie, teeth and implants. Results A total of 229 prostheses were supported by 459 implants and 449 teeth. They were monitored for a period of 2 to 10 years (median follow-up time: 6.7 years). At the end of the different observation periods, 14% of the tooth-implant-supported prostheses had undergone technical modifications, with no statistical difference in the occurrence of technical complications between the 2 types of prosthesis. Three of the functionally loaded implants were removed, while 23 abutment teeth were lost (15 had undergone endodontic treatment). Abutment teeth with a reduced attachment level after prosthesis insertion were significantly affected by biological complications (P = .04). Conclusions The survival data for both types of prosthesis were comparable to prostheses supported solely by implants. There was no difference in the complication rate between primary splinting (fixed) and secondary splinting with telescopic systems (removable). A greater risk of biological complications was recorded for endodontically treated abutments or teeth with a reduced attachment level.

Long-term results of short-span versus long-span fixed dental prostheses: an up to 20-year retrospective study.

Abstract: Purpose This study of short-span fixed dental prostheses (Ss-FDPs) versus long-span FDPs (Ls-FDPs) evaluated the long-term efficacy and determined the frequencies and causes of failures. Materials and methods A total of 236 Ss-FDPs and 86 Ls-FDPs made in an undergraduate university clinic for 149 and 70 patients, respectively, were evaluated over a 20-year period. Kaplan-Meier analysis with a 95% confidence interval was used to estimate the survival probability. Failures of the FDPs were divided into irreversible (loss of FDPs or finish line involvement) or reversible (FDPs and abutments intact after conservative treatment) complications and into biologic and technical/patient-related failures. Results The overall survival estimations for Ss-FDPs (70.8%; 95% Cl: 63%-79%) and Ls-FDPs (52.8%; 36%-70%) at year 20, were statistically significantly different (P = .030). There was no statistically significant difference (P = .126) for the survival estimations for Ss-FDPs (60.4%; 48%-73%) versus Ls-FDPs (59.0%; 44%-74%) at year 19 in the root-canal treated (RCT) group. For the Ss-FDPs group there was a statistically significant difference (P = .009) between the vital (82.4%; 73%-92%) and RCT (60.4%; 49%-73%) groups at year 20. The reason for failure in the Ss-FDP group was of biologic origin in 55.6% to 66.7% of cases, but for the Ls-FDP group the failures were of technical origin in 56.0% to 84.0% of cases. Conclusion The survival of Ss-FDPs and Ls-FDPs over a 20-year period was favorable. The overall survival estimation for Ss-FDPs was statistically significantly better than for Ls-FDPs at year 20. The use of an RCT abutment becomes more significant in fixed prosthetic restorations with 4 or more units. Occurrence of a previously reversible complication is a predictive factor for an irreversible complication later on. A reversible complication within the first 2 years for an Ss-FDP will lead to an irreversible complication.

Perceptions of outcomes of implant therapy in patients with ectodermal dysplasia syndromes.

Abstract: PURPOSE The purpose of this study was to evaluate patient-specific outcomes and satisfaction using dental implants in a population affected with ectodermal dysplasia. MATERIALS AND METHODS Patient-based data were collected using a self-reported survey instrument sent to patients belonging to a private patient foundation and/or treated previously at a government clinic. A standardized survey instrument was developed to evaluate patient satisfaction, outcomes, and potential complications using dental implants. RESULTS The survey instrument was mailed to 253 affected individuals self-reported to have various forms of ectodermal dysplasia and who were voluntarily participants in the National Foundation for Ectodermal Dysplasias and/or were participants in the US National Institute for Dental Craniofacial Research Intramural Ectodermal Dysplasia clinical research program. A total of 109 responses were obtained (43% response rate). The duration following completion of implant therapy ranged from to 1 to 23 years. Of the 109 participants, 50% reported either an implant or prosthetic complication with implant treatment, and 24% reported some form of failure with implant therapy. However, 91% of participants reported being either satisfied or very satisfied with dental implants, and 95% reported that the treatment was worth the time and cost. CONCLUSIONS Affected individuals receiving tooth replacement therapy with dental implants reported satisfaction with the outcome. A higher level of complications, including infection, mechanical problems, and implant loss, relative to the unaffected population was reported.

Clinical evaluation of the efficacy of removing microorganisms to disinfect patient-derived dental impressions.

Abstract: Purpose Disinfection of dental impressions is an indispensable procedure for the control of cross-contamination; however, there is limited information on the efficacy of disinfection under clinical conditions. The objective of this study was to clinically evaluate the disinfection efficacy of commercially available agents in removing oral pathogens from patient-derived impressions. Materials and methods Impressions from 54 patients were divided into groups and either left undisinfected or underwent 1 of 5 disinfection treatments: (1) 2% glutaraldehyde (GA), (2) 1% sodium hypochlorite (SH), (3) 0.25% benzalkonium chloride (BC), (4) 1 ppm ozonated water (OW), or (5) the Hygojet/MD520 system (HJ). An impression culture technique using a brain heart infusion agar medium was used to visualize the microbial contamination on the surface of the impression cultures. The persistent presence of oral pathogens on the impression cultures was examined using selective isolation agar plates. Results The isolation frequencies of streptococci, staphylococci, Candida, methicillin-resistant Staphylococcus aureus, and Pseudomonas aeruginosa species from undisinfected impressions were 100%, 55.6%, 25.9%, 25.9% and 5.6%, respectively. Disinfection with HJ and BC removed the microorganisms with the greatest efficacy, followed by GA, SH, and OW. Potential bacterial contamination could be detected even after disinfection had been performed. Combined use of BC plus GA or SH removed oral pathogens almost completely from dental impressions. Conclusions This investigation showed that potential contaminants are still present, even after general disinfection procedures. Therefore, either HJ or the combined use of BC with GA or SH is recommended for clinical and laboratory use.

Implant prostheses and adjacent tooth migration: preliminary retrospective survey using 3-dimensional occlusal analysis.

Abstract: Occlusal force analysis was retrospectively evaluated to clarify the proximal contact loss after fixed implant prosthesis placement. Twenty-eight patients (55 prostheses) with fixed implant prostheses in the posterior region were divided into 2 groups: proximal contact loss and unchanged groups. The occlusal force and its distribution were 3-dimensionally measured using the Dental Prescale system. A high proportion of lingual and anterior component forces and high occlusal force distribution in the intercanine region were observed in the contact loss group. The high occlusal force of the adjacent tooth may enhance the mesial migration.

Composite resin core-crown reconstructions: an up to 17-year follow-up of a controlled clinical trial.

Abstract: PURPOSE: The aim of this long-term follow-up study was to collect up to 17 years of survival data of endodontically treated single teeth with or without a prefabricated metal post. MATERIALS AND METHODS: Single teeth were provided with direct composite resin core-crown reconstructions with or without posts by 15 operators. Restorations consisted of either a prefabricated metal post and a composite core-crown reconstruction or a post-free direct composite reconstruction. Allocation of either restoration was performed by balanced drawing. These restorations were not covered by an artificial crown. The study sample consisted of 87 patients who received 98 core-crown reconstructions. The performance of the restorations was evaluated based on data collected from the files of the clinicians currently monitoring the oral health of the patients. The survival probability was analyzed at different levels: on the restoration level and on the level of the tooth carrying the restoration. Kaplan-Meier analysis was used to compare survival probabilities. RESULTS: Post placement showed no influence on the survival probability at either level (P > .05). The estimated overall survival rate at 17 years was 53% +/- 14% at the restoration level and 79% +/- 11% at the tooth level. CONCLUSION: The results of this long-term follow-up study showed no difference in survival probabilities between different direct composite resin core-crown reconstructions of endodontically treated single teeth (with or without a post).

Relationship between the frequency of sleep bruxism and the prevalence of signs and symptoms of temporomandibular disorders in an adolescent population.

Abstract: Purpose The relationship between sleep bruxism (SB) and temporomandibular disorders (TMD) is unclear. This study aimed to estimate SB prevalence in an adolescent population and to investigate the relationship between SB frequency and prevalence of TMD signs/symptoms. Materials and methods First-year students at a high school in Okayama, Japan, were recruited in 2005, with 195 subjects responding. The SB detection device was a miniature disposable device (BiteStrip, SLP) that indicated the total SB events per night on a 4-grade score. The subjects were divided into severe and nonsevere SB groups with SB frequency cutoffs. The subjects were examined for temporomandibular joint (TMJ) noise during mouth opening/closing, tenderness of the masticatory/cervical muscles, and range of TMJ condylar movement. The presence/absence of headache and shoulder stiffness was also determined by the interview. The odds ratio (OR) and confidence interval (CI) were calculated to test the relationship between SB frequency, gender difference, and presence of the TMD signs/symptoms by multiple regression analysis. Results Severe SB (more than 125 events per night) was significantly related to the presence of TMJ clicking (OR: 3.74, CI: 1.22-11.49, P = .02), while gender (male) was not related to the presence of TMJ clicking. Severe SB was not related to headache, though gender (male) was significantly related to headache (OR: 2.52, Cl: 1.04-6.11, P= .04) in these subjects. Conclusion These results suggest that the presence of TMJ clicking was closely related to severe SB in an adolescent population.

Prosthetic treatment time and satisfaction of edentulous patients treated with conventional or implant-stabilized complete mandibular dentures: a case-control study (part 2).

Abstract: Purpose: The aim of this study was to compare prospective treatment with implant-retained mandibular overdentures (IROs) versus conventional complete dentures (CDs). This paper reports on the study design and 1-year outcomes. Part 2 in this series will report the 7-year outcomes. Materials and Methods: Sixty edentulous patients with severely resorbed mandibles, already using a conventional CD, participated. Thirty patients received an IRO and 30 received a conventional CD. The patients were retrospectively matched for age, gender, and social class. The length of each treatment session was recorded. Both groups provided a subjective assessment of their current dentures, and satisfaction with their new dentures was evaluated using questionnaires focusing or denture-related complaints and a general satisfaction scale. Results: Patients with IROs were more satisfied with the performance of their dentures than those using conventional CDs, especially with regard to subjective fit, looseness, and quality of chewing, however, more clinical treatment was required. The mean time taken by the prosthodontist to construct CDs was 268 minutes, compared to 327 minutes for IROs, to the time of the second review appointment after insertion. Conclusions: Mandibular IROs provided enhanced performance but required more clinical resources. Int J Prosthodont 2008,21.489-495.

Clinical parameters influencing the accuracy of 1- and 2-stage impressions: a randomized controlled trial.

Abstract: PURPOSE The clinical success of fixed restorations is linked to the precise reproduction of the prepared teeth by dental impressions. The hypothesis under examination was that neither clinical parameters nor the impression technique influenced the reproduction of the finishing line during impression making. MATERIALS AND METHODS For 48 patients who needed a fixed restoration, a 1-stage putty-wash, 2-stage putty-wash, and monophase impression were made after preparation in a randomized order. Clinical parameters (Plaque Index, probing depth, bleeding on probing, Gingival Index, location of the finishing line, bleeding during impression taking, and blood at the impression) were recorded. Master casts were manufactured and optically digitized. Using the data of the 1-stage putty-wash impression as reference, the reproduction of the finishing line was measured 3-dimensionally. Linear models were used for statistical analysis. RESULTS The finishing line was reproduced most precisely by the 1-stage putty-wash technique. Variables with significant influence were the impression technique, blood at the impression, and probing depth. The 2-stage putty-wash impressions showed significantly reduced accuracy compared with the 1-stage impressions. CONCLUSION Clinical parameters and the impression techniques determine the reproduction of the finishing line. The benefit of 2-stage putty-wash impressions with regard to a more complete rendering of subgingival finishing lines should be questioned in light of these results.