Computerized occlusal analysis as an alternative occlusal indicator

Abstract: Objective To investigate whether specific predictive profiles for patient-based risk assessment/diagnostics can be applied in different subtypes of peri-implantitis. Materials and methods This study included patients with at least two implants (one or more presenting signs of peri-implantitis). Anamnestic, clinical, and implant-related parameters were collected and scored into a single database. Dental implant was chosen as the unit of analysis, and a complete screening protocol was established. The implants affected by peri-implantitis were then clustered into three subtypes in relation to the identified triggering factor: purely plaque-induced or prosthetically or surgically triggered peri-implantitis. Statistical analyses were performed to compare the characteristics and risk factors between peri-implantitis and healthy implants, as well as to compare clinical parameters and distribution of risk factors between plaque, prosthetically and surgically triggered peri-implantitis. The predictive profiles for subtypes of peri-implantitis were estimated using data mining tools including regression methods and C4.5 decision trees. Results A total of 926 patients previously treated with 2812 dental implants were screened for eligibility. Fifty-six patients (6.04%) with 332 implants (4.44%) met the study criteria. Data from 125 peri-implantitis and 207 healthy implants were therefore analyzed and included in the statistical analysis. Within peri-implantitis group, 51 were classified as surgically triggered (40.8%), 38 as prosthetically triggered (30.4%), and 36 as plaque-induced (28.8%) peri-implantitis. For peri-implantitis, 51 were associated with surgical risk factor (40.8%), 38 with prosthetic risk factor (30.4%), 36 with purely plaque-induced risk factor (28.8%). The variables identified as predictors of peri-implantitis were female sex (OR = 1.60), malpositioning (OR = 48.2), overloading (OR = 18.70), and bone reconstruction (OR = 2.35). The predictive model showed 82.35% of accuracy and identified distinguishing predictive profiles for plaque, prosthetically and surgically triggered peri-implantitis. The model was in accordance with the results of risk analysis being the external validation for model accuracy. Conclusions It can be concluded that plaque induced and prosthetically and surgically triggered peri-implantitis are different entities associated with distinguishing predictive profiles; hence, the appropriate causal treatment approach remains necessary. The advanced data mining model developed in this study seems to be a promising tool for diagnostics of peri-implantitis subtypes.

Abstract: Objective: Published studies indicate that orthodontically treated patients demonstrate increased posterior occlusal friction contributing to temporomandibular disorder (TMD) symptoms. This study investigated measured excursive movement occlusal contact parameters and their association with TMD symptoms between non- and post-orthodontic subjects.Methods: Twenty-five post-orthodontic and 25 non-orthodontic subjects underwent T-Scan® computerized occlusal analysis to determine their disclusion time (DT), the excursive frictional contacts, and occlusal scheme. Each subject answered a TMD questionnaire to determine the presence or absence of TMD symptoms. Statistical analysis compared the within group and between group differences (p < 0.05).Results: Statistically significant differences were observed in the disclusion time: DT = 2.69 s in the post-orthodontic and 1.36 s in the non-orthodontic group. In the non-orthodontic group, 72.7% working and 27.3% non-working side contacts were seen, while in th...

Abstract: Introduction Evidence-based dentistry (EBD) can help provide the best treatment option for every patient, however, its implementation in restorative dentistry is very limited. Objective This study aimed at assessing the barriers preventing the implementation of EBD among dental undergraduate and graduate students in Montreal, and explore possible solutions to overcome these barriers. Materials and methods A cross-sectional survey was conducted by means of a paper format self-administrated questionnaire distributed among dental students. The survey assessed the barriers and potential solutions for implementation of an evidence-based practice. Results Sixty-one students completed the questionnaire. Forty-one percent of respondents found evidence-based literature to be the most reliable source of information for restorative treatment planning, however, only 16% used it. They considered that finding reliable information was difficult and they sometimes encountered conflicting information when consulting different sources. Dental students had positive attitudes towards the need for better access to evidence-based literature to assist learning and decision making in restorative treatment planning and to improve treatment outcomes. Even for dentists trained in EBD, online searching takes too much time, and even though it can provide information of better quality than personal intuition, it might not be enough to identify the best available evidence. Conclusions Even though dental students are aware of the importance of EBD in restorative dentistry they rarely apply the concept, mainly due to time constraints. For this reason, implementation of EBD would probably require faster access to evidence-based knowledge.

Abstract: Dental occlusion varies among individuals, and achieving correct physiological occlusion after osteotomy is essential for the complex functioning of the stomatognathic system. The T-Scan system records the centre of force, first contact, maximum bite force, and maximum intercuspation. The aim of the present study was to investigate the usefulness and consistency of T-Scan in assessing occlusion before and after orthognathic surgery. Occlusal information was evaluated for 30 healthy adults with normal occlusion and 40 patients undergoing orthognathic surgery. T-Scan had a high degree of reliability for consecutive measurements (Pearson correlation, r = 0.98). For most parameters, occlusal distribution was better after surgery than before surgery. More teeth contributed to occlusion at maximum intercuspation after surgery than before surgery (14 vs. 10). In addition, the difference in the posterior force distribution was reduced after surgery (17.6 ± 13.8 vs. 22.7 ± 21.4 before surgery), indicating better occlusal force distribution after surgery. The maximum percentage force on teeth (p = 0.004) and the number of teeth contributing to occlusion (p < 0.001) also differed significantly. Thus, T-Scan is good for assessing occlusal discrepancies and can be used to portray the pre- and post-operative occlusal contact distribution during treatment planning and follow-up.

Abstract: The occlusal registration of virtual models taken by intraoral scanners sometimes shows patterns which seem much different from the patients’ occlusion. Therefore, this study aims to evaluate the accuracy of virtual occlusion by comparing virtual occlusal contact area with actual occlusal contact area using a plaster model in vitro. Plaster dental models, 24 sets of Class I models and 20 sets of Class II models, were divided into a Molar, Premolar, and Anterior group. The occlusal contact areas calculated by the Prescale method and the virtual occlusion by scanning method were compared, and the ratio of the molar and incisor area were compared in order to find any particular tendencies. There was no significant difference between the Prescale results and the scanner results in both the molar and premolar groups (p = 0.083 and 0.053, respectively). On the other hand, there was a significant difference between the Prescale and the scanner results in the anterior group with the scanner results presenting overestimation of the occlusal contact points (p < 0.05). In Molars group, the regression analysis shows that the two variables express linear correlation and has a linear equation with a slope of 0.917. R2 is 0.930. Groups of Premolars and Anteriors had a week linear relationship and greater dispersion. Difference between the actual and virtual occlusion revealed in the anterior portion, where overestimation was observed in the virtual model obtained from the scanning method. Nevertheless, molar and premolar areas showed relatively accurate occlusal contact area in the virtual model.

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

Abstract: Research in biomaterials and biomechanics has fueled a large part of the significant revolution associated with osseointegrated implants. Additional key areas that may become even more important--such as guided tissue regeneration, growth factors, and tissue engineering--could not be included in this review because of space limitations. All of this work will no doubt continue unabated; indeed, it is probably even accelerating as more clinical applications are found for implant technology and related therapies. An excellent overall summary of oral biology and dental implants recently appeared in a dedicated issue of Advances in Dental Research. Many advances have been made in the understanding of events at the interface between bone and implants and in developing methods for controlling these events. However, several important questions still remain. What is the relationship between tissue structure, matrix composition, and biomechanical properties of the interface? Do surface modifications alter the interfacial tissue structure and composition and the rate at which it forms? If surface modifications change the initial interface structure and composition, are these changes retained? Do surface modifications enhance biomechanical properties of the interface? As current understanding of the bone-implant interface progresses, so will development of proactive implants that can help promote desired outcomes. However, in the midst of the excitement born out of this activity, it is necessary to remember that the needs of the patient must remain paramount. It is also worth noting another as-yet unsatisfied need. With all of the new developments, continuing education of clinicians in the expert use of all of these research advances is needed. For example, in the area of biomechanical treatment planning, there are still no well-accepted biomaterials/biomechanics "building codes" that can be passed on to clinicians. Also, there are no readily available treatment-planning tools that clinicians can use to explore "what-if" scenarios and other design calculations of the sort done in modern engineering. No doubt such approaches could be developed based on materials already in the literature, but unfortunately much of what is done now by clinicians remains empirical. A worthwhile task for the future is to find ways to more effectively deliver products of research into the hands of clinicians.

Abstract: In normal chewing the forces exerted on the occlusal surface seldom exceeded 10 to 15 pounds, as recorded by an eight-channel force transmitter in a removable fixed partial denture. Ninety-five percent of forces were less than 3.5 pounds for subject A, 2.0 pounds for subject B, and 10.0 pounds for subject C. The chewing frequency and the places of maximal force on the occlusal surface were relatively constant. The electromyographic chewing patterns could be considered normal in all circumstances. There was a remarkable statistically significant day-to-day variation in force values. The forces also changed for different kinds of food. The differences between maximum and minimum force values were highest in voluntary, nonfunctional movements.

Abstract: This preliminary study evaluated relationships between masticatory performance and areas of interocclusal distance contact (