Comparison of two arbitrary cast transfer systems with a kinematic facebow for mounting a maxillary cast on a semiadjustable articulator.

STATEMENT OF PROBLEM: The Kois Dento-Facial Analyzer (KDFA) is used by clinicians to mount maxillary casts and to evaluate and treat patients. Limited information is available for understanding whether the KDFA should be considered as an alternative to an arbitrary facebow. PURPOSE: The purpose of this clinical study was to evaluate and compare maxillary casts mounted by using the KDFA with casts mounted by using the Panadent Pana-Mount Facebow (PMF) and a kinematic axis (KA) facebow. MATERIAL AND METHODS: Fifteen participants were enrolled in the study. Three maxillary impressions were made of each study participant. One cast from each study participant was mounted on an articulator by means of the KDFA, PMF, and KA. A standardized photograph of each mounting was made, and the condylar center-incisor distance and the occlusal and incisal plane angles were measured. A randomized complete block design analysis of variance (RCBD) (α=.05) and post hoc tests (Tukey-Kramer HSD) were used to evaluate the occlusal and incisal plane angles and the condylar center-incisor distance. RESULTS: Compared with the occlusal plane angle (OPA), the KDFA mounted the maxillary cast at an angle that was statistically lower than those of PMF and KA (P<.001). The KDFA and the PMF condylar center-incisor distances were both significantly greater than that of KA (P=.01). No differences were found between the incisal plane angle (IPA) on maxillary casts mounted with the KDFA, KA, or PMF (P=.16). CONCLUSIONS: The KDFA and PMF mounted the maxillary casts in a position that was farther from the axis when compared with the KA mounted casts. The KDFA resulted in a lower articulator OPA compared with both PMF and KA. No difference was found between the IPAs of the KDFA, PMF, and KA.

The Effect of Patient Specific Factors on Occlusal Forces Generated: Best Evidence Consensus Statement.

PURPOSE: The purpose of this Best Evidence Consensus Statement was to search the literature to determine if there is a relationship between patient specific factors and occlusal force. MATERIALS AND METHODS: A literature review was conducted in the following databases: Evidence-Based Medicine Reviews (EBMR), Cochrane Database of Systematic Reviews, Embase, and Ovid MEDLINE(R) and Epub Ahead of Print. Articles on patient factors and occlusal force were compiled by using a combination of the key words: "bite force," "occlusal force," "partial and complete edentulism," "bruxism," and "orthognathic class." Inclusion criteria included meta-analyses, systematic reviews, randomized controlled trials, case series, and journal articles. Exclusion criteria were case reports, studies in children, animals, and bench studies. RESULTS: Of the 1502 articles that met the initial search criteria, 97 related to patient-specific factors affecting occlusal forces. These articles were evaluated, rated, and organized into appropriate categories addressing questions of foci. CONCLUSIONS: The range of occlusal force is highly variable among subjects correlated to patient specific factors such as age, gender, partial and complete edentulism, the presence of a maxillofacial defect, location of edentulous area, orthognathic profile, and magnitude of occlusal vertical dimension. Tooth replacement therapies targeted at increasing occlusal contact seem to have a positive effect on increasing occlusal force. Bruxism does not necessarily demonstrate higher occlusal powering but may have greater tooth contact time. Occlusal force is not clearly affected by the type of dental restoration or restorative material used. The clinical significance of the changes in occlusal forces is yet to be determined.

Does the Stomatognathic System Adapt to Changes in Occlusion? Best Evidence Consensus Statement.

PURPOSE: The purpose of this Best Evidence Consensus Statement was to evaluate the existing literature on the stomatognathic system's ability to adapt to occlusal changes. MATERIALS AND METHODS: The search term stomatognathic system was not useful as it resulted in over 400,000 results nor was the search term temporomandibular joint adaptation with 738 results due to the large number of references not related to the topic. The terms stomatognathic system adaptation to occlusal changes (186 results), teeth flexion (139 results), muscle adaptation to dental occlusion (278 results), and occlusal changes and neuroplasticity (11 results) provided the best selection of articles related to the topic. Limiting the above searches to systematic reviews and randomized controlled clinical trials resulted in multiple publications that were related to the question.9-13 Other literature reviews, data-based publications, and expert opinion resources have been included due to their relationship to the question. RESULTS: From the extensive list of search results, 242 articles were determined to be potentially related to the focus question and were evaluated with 56 being included in this paper. It was determined that the stomatognathic system adapts to occlusal changes through the temporomandibular joint, muscles, teeth and bone. The dynamically modified periosteum on the articulator surfaces of the condyle and fossa has a unique load-bearing morphology with 3 subarticular layers of fibrocartilage that absorb and dissipate both peak (impact) and sustained loads. Adaptability of the TMJs and muscles can be documented through studies where artificially produced occlusal interferences were placed in patients and those study participants with normal temporomandibular joints (TMJs) adapted fairly well whereas those with a previous history of temporomandibular disorders (TMD) did not adapt as well. CONCLUSIONS: Available evidence indicates patients generally adapt to the occlusal change inherent in orthodontic treatment, mandibular advancement surgery, and the use of mandibular advancement devices. The head and neck muscles also adapt to occlusal changes in patients without a history of TMD. The dentition adapts to changes through the bone and periodontal ligaments as well as the ability of teeth to undergo slight flexion under masticatory loading. This article is protected by copyright. All rights reserved.

Defining centric relation.

STATEMENT OF PROBLEM: Multiple definitions of centric relation (CR) have evolved over time that may have created confusion or impeded understanding. A recent attempt to achieve a singular definition by surveying the members of the Academy of Prosthodontics (AP) did not achieve majority consensus. PURPOSE: The purpose of this study was to identify those aspects or attributes within the existing definitions of CR in which there was agreement or disagreement among the members of the AP. MATERIAL AND METHODS: After pretesting and institutional review board approval, a second survey of the AP membership was performed using both email and postal mail survey methods of contact. The CR Attributes Survey separated and stratified the previous definitions of CR into 5 domains: spatial relationship, condylar position, articular disks, mandibular movement, and recording. Each domain attribute was evaluated by agree-uncertain-disagree assessments. Also recorded were demographics, perception of scientific evidence, and open comments. RESULTS: Of the total 146 fellows, 100 completed the survey for an overall response rate of 68.5%. The query completion rate ranged from 96% to 98%. The CR Attributes Survey revealed those components within each domain in which there was strong agreement, disagreement, or uncertainty. The survey assessment of those queries with a moderate to strong agreement were that CR is a "spatial relationship" that is (1) a clinically determined relationship of the mandible to the maxilla, (2) a repeatable position, (3) is independent of tooth contact, and (4) is a physiologic position. Relative to "disks," the condyles articulate with the thinnest avascular intermediate zone of their respective disks; however, there is a lack of sufficient evidence to determine the position of the disks and the condyles. Relative to "mandibular movement," CR is (1) a starting point for vertical, lateral, or protrusive movements, (2) is where the individual can make to and from lateral movements, and (3) is restricted to pure rotary movement about a transverse horizontal axis. Relative to "recording CR" (1) it can be determined in patients without pain or derangement of the temporomandibular joints (TMJs), (2) but may not be recordable in the presence of dysfunction of the masticatory system, or (3) due to the neuromuscular influence or proprioception from the dentition, (4) is a clinical useful repeatable reference position for mounting casts, or (5) for developing a functional treatment occlusion, (6) at an established vertical dimension, and (7) may vary slightly by recording method. CONCLUSIONS: The CR Attributes Survey revealed a majority agreement or consensus for various CR attributes that should be considered for defining the term 'centric relation.' In contrast, those CR attributes with a plurality agreement, disagreement, or uncertainty outcomes should be considered for exclusion. The evaluated weakness of these latter attributes indicates the need for further research and reassessment.

Clinical significance of immediate mandibular lateral translation: A systematic review.

STATEMENT OF PROBLEM: Immediate mandibular lateral translation (IMLT) has been widely described in theory, but its clinical significance in prosthodontics and restorative dentistry is not clear. PURPOSE: The purpose of this study was to systematically review the existing literature to identify the clinical significance of IMLT (immediate side shift). MATERIAL AND METHODS: An electronic search for articles in the English language literature was performed independently by multiple investigators using a systematic search process with the PubMed search engine. After applying predetermined inclusion and exclusion criteria, the final list of studies was analyzed to identify the clinical significance of IMLT. RESULTS: The initial electronic search yielded 858 titles. The systematic application of the inclusion and exclusion criteria eventually produced 23 studies addressing IMLT in 914 human participants. Eleven studies reported use of voluntary movements, 5 articles reported use of only induced movements, 2 studies reported use of both voluntary and induced movements, and 5 articles did not report the recording method. The amount of IMLT reported ranged from 0 to 3 mm with minimal clarity among authors on the exact description of IMLT. No studies reported on any clinical implication (harm or benefit to patients or clinicians) of incorporating IMLT in diagnosis and treatment planning. CONCLUSIONS: This systematic review did not identify any scientific evidence on the clinical implications of IMLT. Furthermore, there is a lack of clear terminology related to IMLT and the timing of the side shift, occurrence of IMLT on the working versus nonworking condyle, and induced versus noninduced methods of recording and measuring. Current scientific evidence does not support the need to include IMLT as a factor when prosthodontic or restorative treatment is planned and executed.

A progressive approach for the use of occlusal devices in the management of temporomandibular disorders.

Temporomandibular disorders (TMDs) represent a broad spectrum of conditions associated with the temporomandibular joints and the neuromuscular system. Evidence-based diagnostic criteria for various TMDs are emerging, while corresponding treatment procedures remain less clear. As a result, the clinician may be uncertain how to best care for TMD patients. The objectives of this evidence-based review were to outline the various types of occlusal devices, assess the efficacy of occlusal splints in treating TMD patients, and create a treatment rubric based on diagnostic criteria and condition severity. A select literature review as to the effectiveness and efficacy of occlusal device TMD therapy revealed that stabilization splint intervention and control treatments had a positive effect in reducing TMD-related symptoms; minimal statistically significant differences were noted between intervention and control treatments. Stabilization splints are effective as a reversible treatment for patients with TMD. Other therapies and occlusal devices may be beneficial when used for a specific TMD diagnostic protocol. A treatment rubric based on diagnostic criteria and condition severity may assist the clinician.

Assessment of occlusion curriculum in predoctoral dental education: report from ACP Task Force on Occlusion Education.

PURPOSE: The purposes of this report were to (1) assess the current occlusion curriculum in the predoctoral prosthodontic education of US dental institutions and (2) to examine the opinions of faculty, course directors, and program directors on the contents of occlusion curriculum. MATERIALS AND METHODS: The Task Force on Occlusion Education from the American College of Prosthodontists (ACP) conducted two surveys using a web-based survey engine: one to assess the current status of occlusion education in predoctoral dental education and another to examine the opinions of faculty and course directors on the content of occlusion curriculum. The sections in the surveys included demographic information, general curriculum information, occlusion curriculum for dentate patients, occlusion curriculum for removable prosthodontics, occlusion curriculum for implant prosthodontics, temporomandibular disorder (TMD) curriculum, teaching philosophy, concepts taught, and methods of assessment. The results from the surveys were compiled and analyzed using descriptive statistics. The results from the two surveys on general concepts taught in occlusion curriculum were sorted and compared for discrepancies. RESULTS: According to the predoctoral occlusion curriculum surveys, canine guidance was preferred for dentate patients, fixed prosthodontics, and fixed implant prosthodontics. Bilateral balanced occlusion was preferred for removable prosthodontics and removable implant prosthodontics. There were minor differences between the two surveys regarding the occlusion concepts being taught and the opinions of faculty members teaching occlusion. CONCLUSION: Two surveys were conducted regarding the current concepts being taught in occlusion curriculum and the opinions of educators on what should be taught in occlusion curriculum. An updated and clearly defined curriculum guideline addressing occlusion in fixed prosthodontics, removable prosthodontics, implant prosthodontics, and TMD is needed.

Occlusal stability.

Occlusion is the foundation for clinical success in fixed, removable, and implant prosthodontic treatment. Understanding those principles is critical when restoring a patient's occlusion. Many philosophies, devices, and theories of occlusion have evolved based on anecdotal clinical observations and applied geometric perceptions. The literature has reported these classic and contemporary occlusal concepts. As evidence-based dentistry emerged, it championed scrutiny of previously held beliefs, resulting in the abandonment of many pragmatic, yet beneficial occlusal procedures. The impetus toward scientific discovery, whereby factual information might be universally applied in dental education and clinical practice, has renewed interest in occlusal studies.

Occlusion for fixed prosthodontics: a historical perspective of the gnathological influence.

This article addresses the historical perspective of the gnathological influence upon the concepts of occlusion for fixed prosthodontics. A critical assessment and subsequent scientific validation of occlusal theories require an understanding of their evolution in the formative years and the subsequent development of effective models for clinical practice. While gnathological concepts offer a structured methodology for prosthodontic procedures, further research is needed to corroborate current occlusal treatment approaches. This review focuses on the "classic" fixed prosthodontic literature and the currently available scientific literature involving fixed prosthodontic dentate occlusion and gnathology. A MEDLINE search was performed to identify English-language peer-reviewed publications spanning the last 56 years, along with an extensive hand search for years prior. Electronic searches of the literature were performed in MEDLINE using the key words: case series, clinical trials, cohort studies, fixed partial denture occlusion, dental occlusion, dental occlusion research, centric relation, incisal guidance, maximal intercuspation, occlusal vertical dimension, and occlusion, in various combinations to obtain potential references for review. A total of 10,382 English-language nonduplicate titles were obtained for 1950-2006 for the key words "dental occlusion." Other key word searches produced smaller numbers of articles, many of which were duplicates due to multiple searches and were subsequently eliminated. Manual hand searching of the MEDLINE reference list and other journals of interest was performed to identify any articles missed in the original search. Articles were included for review if they contained emerging occlusal theories, new technologies, or occlusal studies that included multiple subjects in contrast to case reports.

Factors affecting soft tissue around dental implants: a review of the literature.

Much of the focus in the early dental implant literature is on the bone-to-titanium interface because a successful osseointegrated implant requires direct bone contact to the implant surface. The research on soft tissue around dental implants has focused on the partially edentulous patient and, in particular, on the maxillary anterior dentition. Few studies have evaluated soft tissue around dental implants in completely edentulous patients over time. This paper reviews the pertinent literature on soft-tissue healing in both partially and completely edentulous dental implant patients from a Medline search of the English peer-reviewed literature from 1980 to 2004.

The use of distraction osteogenesis to treat hemifacial microsomia: a clinical report.

Distraction osteogenesis is a method of forming bone through osteotomy and sequential stretching of the healing callus. This process is accomplished with the aid of a distraction device, which is secured with screws placed directly into bone for a predetermined length of time. This clinical report describes the use of distraction osteogenesis to treat mandibular asymmetry in a patient with Goldenhar's syndrome, a form of hemifacial microsomia. After treatment, the patient had a more rounded facial contour and corrected occlusal plane.

Can we assess quality of life in patients with head and neck cancer? A preliminary report from the American Academy of Maxillofacial Prosthetics.

Survival statistics alone may no longer be valid when used as evidence of effective outcomes. Patient satisfaction is an end point that needs further evaluation and should be included in the outcomes assessment. A 133-item questionnaire has been designed by a special committee of the American Academy of Maxillofacial Prosthetics (AAMP) to assess the quality of life of patients with head and neck cancer impacting the orofacial region. This survey will be distributed to the entire population of 7 geographically dispersed treatment centers in the United States for a 2-year period. Patients will be stratified into several subgroups, including radiation/nonradiation, maxillary/mandibular, and surgical reconstruction/prostheses. Separate analyses will be conducted for each subgroup, and comparisons will be made within subgroups to test the sensitivity of the questionnaire to a known difference. A revised version of the AAMP questionnaire, limited to 50 items of interest to patients, will be validated against 2 established head and neck cancer questionnaires. This article provides background on previous quality-of-life studies and reviews the need for and aims of the AAMP assessment instrument.