Analysis of occlusal variables, dental attrition, and age for distinguishing healthy controls from female patients with intracapsular temporomandibular disorders

Dental Attrition and its Association With the Signs and Symptoms of TMJ Dysfunction and Radiographic Condylar Changes - An Observational Study

To determine the level of dental attrition and its relation to signs of TMJ dysfunction adding to condylar alterations analyzed by conventional TMJ Tomography and to propose the correlation between dental attrition and signs of TMJ dysfunction and condylar changes. Patients for the study were selected from the regular outpatient Department of Oral Medicine, Diagnosis and Radiology, Rajah Muthiah Dental College and Hospital, Annamalai University, Chidambaram, with performed criteria. The radiographic examination of TMJ is performed by the PLANMECA OPG machine using the tomographic program. Statistical analysis was performed using a Chi-square test to determine the relation between attrition and temporomandidular disorders [TMD] signs and symptoms. The study group comprises 60 subjects who are having dental attrition, and they are divided into three groups according to their age: Group I, 20-40 age; Group II, 41-60 age; Group III, more than 60 age 80% of the samples had one or more tooth with significant attrition with grades of two or more on a 0-4 scale The prevalence of changes in condylar morphology was more in individuals above 40 yrs (33.33%) as compared to those below the age of 40 with a total prevalence of 41.67%. The most common symptom reported is tooth sensitivity, joint sounds, and muscle tenderness. The last reported are scalloped tongue, buccal mucosa ridging, referred pain, and limitation of mouth opening. Out of the 25 subjects who showed condylar changes, 10 subjects had symptoms of TMD. The symptoms reported are strain in the mouth opening, tenderness in jaw movements, and TMJ clicking sounds. Attrition is not a predictable sign of TMJ dysfunction, yet a finite association was defined between attrition and signs and symptoms of TMJ dysfunction. Studies involving larger samples compared with additional radiographic modalities are recommended.

Radiological Associations between Posterior Edentulism and Condylar Bony Changes: A Retrospective Study

This retrospective study aimed to investigate the relationship between posterior edentulism and condylar bone changes in patients aged 35-60 years. The CBCT images of 259 patients, including 131 posterior edentulous and 128 posterior dentulous patients, were analyzed to identify the types of condylar bone changes. The frequency of flattening, sclerosis, erosion, and reduced joint space was found to be higher in posterior edentulous patients. Regression analysis revealed that combined premolar and molar loss and being female were significant predictors of condylar erosion (p = 0.006; OR: 3.264; 95% CI: 1.401 - 7.603, p=0.031; OR: 2.652; %95 CI: 1.095 - 6.424). The study provides support for the domino effect phenomenon in temporomandibular joint pathology, indicating that posterior edentulism can have a significant impact on the occurrence of erosive condylar changes. The findings suggest that prosthetic and temporomandibular joint treatment approaches should consider the association between posterior edentulism and condylar bone changes, particularly in female patients with combined premolar and molar loss. Therefore, close attention should be paid to the management of these patients to minimize the risk of temporomandibular joint pathology.

The association of severely worn dentition resulting from betel nut chewing with temporomandibular disorders: a cross-sectional study

BACKGROUND

Most studies support parafunctions play an important role in temporomandibular disorders (TMD), whereas the association between tooth wear and TMD remains controversial. Betel nut chewing as a parafunction is popular in South and Southeast Asia. We therefore investigated the association of severely worn dentition resulting from betel nut chewing with TMD.

METHODS

A cross-sectional analysis of 408 control participants (male: 380, female: 28, 43.62 ± 9.54 years) and 408 participants with betel nut chewing related severely worn dentition (male: 380, female: 28, 43.73 ± 8.93 years) who received dental and TMD checkup according to Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) in Health Management Center, Xiangya Hospital was performed. Betel nut chewing related severely worn dentition meant all the natural teeth had moderate to severe tooth wear [Tooth Wear Index (TWI) ≥ 2)] including ≥ 2 severe wear teeth (TWI ≥ 3) due to betel nut chewing. Multivariable logistic regression analysis was used.

RESULTS

After adjusting for age, gender, betel nut chewing related severely worn dentition, oral submucosal fibrosis, number of missing teeth, number of dental quadrants with missing teeth, visible third molar and orthodontic history, variables of age, gender and betel nut chewing related severely worn dentition were significant for overall TMD. Multivariable analysis showed betel nut chewing related severely worn dentition was significantly associated with intra-articular TMD [odds ratio and 95% confidence intervals: 1.689 (1.271-2.244), P = 0.001] in a betel nut chewing dose-dependent manner.

CONCLUSION

Betel nut chewing related severely worn dentition was associated with intra-articular TMD.

Prevalence of sagittal molar and canine relationships, asymmetries and midline shift in relation to temporomandibular disorders (TMD) in a Finnish adult population

OBJECTIVE

To examine the prevalence of sagittal relationships, asymmetries and midline shift, and their associations with temporomandibular disorders (TMD) in the Northern Finland Birth Cohort 1966 (NFBC1966).

MATERIALS AND METHODS

1845 subjects participated in a clinical examination at the age of 46. Occlusal measurements were performed using 3D models. Symptoms of TMD were screened using validated questions, and signs and diagnoses of TMD were assessed using a modified protocol of the Diagnostic Criteria for TMD (DC/TMD) and questionnaires. Associations between variables of occlusion and TMD were evaluated with χ²-test and Fisher's exact test and using logistic regression analyses, adjusted for self-reported general health, mental health, bruxism, and rheumatoid arthritis.

RESULTS

The most common sagittal relationships were Class I and normal canine relationship. Half-cusp Class II and post-normal canine relationship were more frequent in females, and Class III and pre-normal canine relationship in males. Deviations from normal cuspid or molar relationships showed a weak but statistically significant association with TMD, especially in females. Half-cusp Class II and Class II relationships were more frequent in relation to joint-related TMD signs and diagnoses while missing canines were associated with pain-related TMD diagnoses.

CONCLUSIONS

The present study findings gave some indications that canine relationships are associated with pain-related TMD, whereas Angle II sagittal occlusal relations may associate with joint-related TMD. Occlusal characteristics should therefore be taken into account as one possible associating factor in subjects with TMD.

Effects of Prosthetic Rehabilitation on Temporomandibular Disorders: Protocol for a Randomized Controlled Trial

Background

Loss of teeth or occlusal imbalance is one of the proposed dental risk factors for temporomandibular disorders (TMDs). Losing some non–free-end teeth cause the original occluding tooth/teeth to supraerupt from the original upright position and causes neighboring tooth/teeth to shift in an angle, causing biomechanical imbalance on the mandible. Based on these sequelae, rehabilitation of missing teeth is the first step in managing TMD in edentulous patients. Even though the prevalence of TMD in association with edentulism and in rehabilitated patients has been increasing, proper guidelines for the management of such cases have not been established. This study describes the protocol to analyze the effect of prosthetic rehabilitation on patients with TMD.

Objective

This study aims to determine the effectiveness of prosthetic rehabilitation in the reduction of pain in edentulous patients with TMD and to determine the effect of the span of edentulism, the number of quadrants involved, pathological migration, the type of Kennedy classification, and the prosthetic status on temporomandibular joint dysfunction signs and symptoms.

Methods

In this randomized controlled trial, 300 patients diagnosed with TMD will be grouped into one of the three interventional groups based on the type of their edentulous state. The interventional groups are (1) partially edentulous arch: Kennedy Class I and II (prosthetic rehabilitation without splint); (2) partially edentulous arch: Kennedy Class III and IV (prosthetic rehabilitation with a splint); and (3) completely edentulous arches (prosthetic rehabilitation without splint). All three of the mentioned interventional groups have corresponding control groups that will receive symptomatic treatment and comprehensive counseling. The measured primary outcomes are pain and electromyogram, and the secondary outcomes include pain drawing, Graded Chronic Pain Scale, Jaw Functional Limitation Scale, Oral Behaviours Checklist, depression, physical symptoms, and anxiety. The outcome measurements will be recorded at baseline and at the end of 24 hours, 7 days, 28 days, and 3 months.

Results

Ethical approval was obtained from the Institutional Review Board of Amrita Institute of Medical Sciences, Kochi, India. Study participants’ recruitment began in May 2021 and is expected to conclude in March 2023. This clinical trial protocol was developed based on the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) 2013 Statement.

Conclusions

The purpose of this study is to gather data on prosthetic rehabilitation as a treatment for TMD. Obtaining this goal will aid in the development of evidence-based therapy protocols for prosthetic rehabilitation in TMD management.

Trial Registration

Clinical Trials Registry - India CTRI/2020/06/026169; http://ctri.nic.in/Clinicaltrials/pdf_generate.php?trialid=42381

International Registered Report Identifier (IRRID)

DERR1-10.2196/33104

Adjustment of Occlusal Splint with Synchronized T-Scan III Digital Occlusal Analysis System and Bio-EMG III in a Patient with Sleep Bruxism

The occlusal splint has been frequently used as an effective treatment in sleep bruxism patients. In the adjustment procedure of occlusal splint with an optimal occlusion, clinicians usually use conventional methods; however, they cannot measure the surface area of contacts, amount of force, and contacting time sequence. Recently, two separate technologies have been synchronized together: T-Scan III and BioEMG III. In the present case report, an occlusal splint in a patient with sleep bruxism was adjusted with synchronized T-Scan computerized digital occlusal analysis system and BioEMG III. Optimal occlusal parameters were generated, and quantitative analyses of occlusal scheme and muscle activity level were performed before and after the adjustment of the occlusal splint.

In the present case report, occlusion of the occlusal splint in a bruxism patient was adjusted with T-Scan III to fulfill the requirement of the optimal occlusion criteria. Before adjustment of occlusal splint, digital evaluation revealed unbalanced force distribution, lengthy occlusion (1.51 s), and disocclusion time (0.09 s) in centric relation. EMG activity of muscles was lower than expected values in centric relation. After adjustment of occlusal splint, canine protected occlusion with appropriate occlusion (0.2 s) and disocclusion (0.4 s) time were performed. Increased electromyography activity of the right anterior temporalis muscle showed a decrease in all excursive movements. Modern occlusal adjustment procedures provide a new standard of verification for the validation of occlusal splint fabrication with optimal occlusion.

Relationship between Pathological Occlusal Changes and the Signs and Symptoms of Temporomandibular Dysfunction

Objective

This study aimed to investigate whether there is a correlation between pathological occlusal changes and the signs and symptoms of temporomandibular dysfunction (TMD).

Methods

This cross-sectional, quantitative, non-randomized clinical trial was conducted on 150 participants. We examined adult patients of both genders with occlusal interference, malocclusion and dental absence in the posterior region of the dental arch that were associated or not associated with painful symptoms. The questionnaire was administered, and the intra- and extra-oral clinical examination was performed on each patient, including the evaluation of the temporomandibular joint (TMJ) to investigate the presence of dysfunction.

Results

The mean age of the participants was 33 years (±2.3), and 103 (68.7%) of them were women and 47 (31.3%) were men. Tooth loss and malocclusion were more prevalent in females. Tooth loss showed a statistically significant association with all the signs and symptoms of TMD (p=0.02). Patients with multiple teeth losses experienced preauricular pain during mandibular opening and closing. There was no association between malocclusion with tooth loss and the signs and symptoms of TMD in 65 patients (p>0.05).

Conclusion

Only in the patients with Class II malocclusion there was a significant association with 2 signs of TMD (crackling and bruxism). There was no association between malocclusion and tooth loss with the signs and symptoms of TMD. The signs and symptoms of TMD were more frequent in the patients who presented multiple teeth loss without malocclusion.

Occlusion and Temporomandibular Disorders: A Long-Standing Controversy in Dentistry

The relationship between temporomandibular disorders (TMDs) and occlusion remains controversial. Some authors believe that occlusion is the primary factor in the onset of TMD symptoms, whereas others feel that occlusion has no role in this at all. The majority of reasoning behind causation is based upon anecdotal rather than scientific evidence. Existing evidence in the literature supports the absence of a disease-specific association. This article describes this controversy and provides the reader with findings from contemporary literature.

Identifying At-Risk Subgroups for Acute Postsurgical Pain: A Classification Tree Analysis

Objective

Acute postsurgical pain is common and has potentially negative long-term consequences for patients. In this study, we evaluated effects of presurgery sociodemographics, pain experiences, psychological influences, and surgery-related variables on acute postsurgical pain using logistic regression vs classification tree analysis (CTA).

Design

The study design was prospective.

Setting

This study was carried out at Chongqing No. 9 hospital, Chongqing, China.

Subjects

Patients (175 women, 84 men) completed a self-report battery 24 hours before surgery (T1) and pain intensity ratings 48-72 hours after surgery (T2).

Results

An initial logistic regression analysis identified pain self-efficacy as the only presurgery predictor of postoperative pain intensity. Subsequently, a classification tree analysis (CTA) indicated that lower vs higher acute postoperative pain intensity levels were predicted not only by pain self-efficacy but also by its interaction with disease onset, pain catastrophizing, and body mass index. CTA results were replicated within a revised logistic regression model.

Conclusions

Together, these findings underscored the potential utility of CTA as a means of identifying patient subgroups with higher and lower risk for severe acute postoperative pain based on interacting characteristics.

Toll-Like Receptor 4 (TLR4) Stimulates Synovial Injury of Temporomandibular Joint in Rats Through the Activation of p38 Mitogen-Activated Protein Kinase (MAPK) Signaling Pathway

Background

Synovitis is an important disease that cause intractable pain in temporomandibular joint (TMJ), and the inflammation process played a crucial role in the initiation and development of temporomandibular joint disorder. A series of investigations suggested that the increasing expression of interleukin-(IL) 1β secreted by synovial lining cells plays an important role in synovial inflammation and cartilage destruction in TMJ. In this present study, we investigated the signaling pathways which regulate the expression of IL-1β.

Material/Methods

The occlusal interference animal model was created to induce synovial injury. Forty-eight rats were divided into 4 groups: 1) control group, 2) occlusal interference group, 3) TAK-242 (a specific inhibitor targeting the Toll-like receptor (TLR)-4) group, and 4) SB203580 (a specific inhibitor targeting the p38) group. The inflammation changes were observed, and the expression of p38 and IL-1β in the synovial membranes were assayed.

Results

The results showed that downstream p38 MAPK (mitogen-activated protein kinase) signaling was triggered following the activation of TLR4. Moreover, the injection of SB203580 could inhibit the inflammatory reactions and the increased expression of IL-1β at both mRNA and protein levels.

Conclusions

The results prompted us that TLR4 may stimulates synovial inflammatory reactions and increased expression of IL-1β in rats through the activation of p38 MAPK signaling pathway, p38 was an important mediator in the mechanisms of the initiation and development of synovial injury by regulating the expression of IL-1β in synovial membranes.

The knowledge level of dental surgeons regarding the relationship between occlusal factors and Temporomandibular Disorders (TMD)

AbstractIntroductionThe relationship between dental occlusion and temporomandibular disorders (TMD) remains a subject of disagreement. Many professionals erroneously base diagnosis and treatment strictly on the occlusal factor, despite the fact that current scientific evidence does not show such a relationship.ObjectiveTo evaluate the knowledge of dental surgeons (DSs) from João Pessoa (PB)-Brazil, regarding the relationship between occlusal factors and TMD.Materials and methodA sample of 100 DSs who do not have expertise in TMD and orofacial pain (CG Group) and seven DSs with this specialty (EG Group) completed a questionnaire that addresses issues concerning knowledge of TMD and its relationship with occlusal factors. The questionnaire also contained information used to characterize the sample, such as age, gender, and length of experience. The current literature's degree of consensus was established as the "gold standard" response for each statement and was compared with the responses of the specialists and non-specialists. Data were tabulated using the SPSS software package and analyzed descriptively (by percentage) and statistically using the chi-square and Fisher's exact tests (p < 0.05).ResultA wide divergence could be observed between the knowledge of DSs who do not specialize in TMD and orofacial pain and that of professionals who do.ConclusionThere was low agreement between specialists and non-specialists. The relationship between dental occlusion and TMD remains unclear for the vast majority of participating professionals, which may prove to be reflected in diagnostic behaviors and inappropriate occlusal treatment for the management of TMD.

3D Simulation Modeling of the Tooth Wear Process

Severe tooth wear is the most common non-caries dental disease, and it can seriously affect oral health. Studying the tooth wear process is time-consuming and difficult, and technological tools are frequently lacking. This paper presents a novel method of digital simulation modeling that represents a new way to study tooth wear. First, a feature extraction algorithm is used to obtain anatomical feature points of the tooth without attrition. Second, after the alignment of non-attrition areas, the initial homogeneous surface is generated by means of the RBF (Radial Basic Function) implicit surface and then deformed to the final homogeneous by the contraction and bounding algorithm. Finally, the method of bilinear interpolation based on Laplacian coordinates between tooth with attrition and without attrition is used to inversely reconstruct the sequence of changes of the 3D tooth morphology during gradual tooth wear process. This method can also be used to generate a process simulation of nonlinear tooth wear by means of fitting an attrition curve to the statistical data of attrition index in a certain region. The effectiveness and efficiency of the attrition simulation algorithm are verified through experimental simulation.

Correlação entre sinais e sintomas da Disfunção Temporomandibular (DTM) e severidade da má oclusão

Introdução O papel da oclusão como fator etiológico das disfunções temporomandibulares (DTMs) tem sido um assunto polêmico e ainda controverso. Objetivo Avaliar a correlação entre sinais e sintomas da disfunção temporomandibular e a severidade da má oclusão. Método Foram avaliados 135 estudantes de Odontologia da UFPB. A presença de DTM foi estimada através do Índice Anamnésico de Fonseca (DMF) e de questões objetivas sobre seus sintomas. Os estudantes também foram submetidos a um protocolo resumido de avaliação clínica de DTM. A avaliação dos fatores oclusais foi realizada através do Índice de Prioridade de Tratamento (IPT) aplicado a modelos de gesso dos arcos dentários superior e inferior. As diferenças entre as médias do IPT relacionadas aos sinais e sintomas de DTM foram determinadas por meio dos testes t e One-way ANOVA. As correlações entre os fatores oclusais e a DTM foram determinadas a partir de correlação de Pearson. Resultado A severidade da má oclusão, segundo o IPT, não influenciou no surgimento de DTM e de sinais clínicos musculares ou articulares, e na necessidade de tratamento. A má oclusão de classe II, trespasse vertical acentuado e dentes girados foram estatisticamente correlacionados à necessidade de tratamento e aos sinais clínicos de DTM. Conclusão Em modelos multifatoriais, como na fisiopatologia da DTM, a oclusão pode desempenhar um papel de cofator na predisposição ou perpetuar as diferentes formas de DTM, não devendo ser considerada fator principal.

Effect of TLR4/MyD88 signaling pathway on expression of IL-1β and TNF-α in synovial fibroblasts from temporomandibular joint exposed to lipopolysaccharide

Accumulating evidence from previous studies suggested that interleukin-1 (IL-1β) and tumor necrosis factor-α (TNF-α) play an important role in pathogenesis of temporomandibular disorders (TMD). However, the cell surface receptors and the intracellular signal pathways leading to these cytokines expression are not fully understood. In the current study, we investigated the roles of Toll-like receptor 4 (TLR4) and its adaptor myeloid differentiation factor 88 (MyD88) in the expression of IL-1β and TNF-α in synovial fibroblasts (SFs) separated from rat temporomandibular joint (TMJ) with lipopolysaccharide (LPS) stimulation. The results showed that treatment with LPS could increase TLR4, MyD88, IL-1β, and TNF-α expression at both mRNA and protein levels. In addition, increased expression of IL-1β and TNF-α could be blocked by treatment with TAK-242, a blocker of TLR4 signaling, and also by MyD88 inhibitory peptide (MIP). These findings suggested that maybe TLR4/MyD88 signal transduction pathway participates in enhanced expression of IL-1 and TNF-α in patients with TMD. The activation of TLR4/MyD88 signal transduction pathway which results in production of proinflammatory factors may play a role in the pathogenesis of TMD.

Clinical issues in occlusion - Part I

Good occlusal practise provides an important cornerstone to optimal patient care. Occlusal problems can manifest in different areas of dentistry but these are more apparent when there are restorative aspects to the patient׳s problem. This review highlights areas of restorative dentistry where the appreciation of occlusal aspects can optimise diagnosis and follow up care.

Electromyogram biofeedback training for daytime clenching and its effect on sleep bruxism

Bruxism contributes to the development of temporomandibular disorders as well as causes dental problems. Although it is an important issue in clinical dentistry, no treatment approaches have been proven effective. This study aimed to use electromyogram (EMG) biofeedback (BF) training to improve awake bruxism (AB) and examine its effect on sleep bruxism (SB). Twelve male participants (mean age, 26·8 ± 2·5 years) with subjective symptoms of AB or a diagnosis of SB were randomly divided into BF (n = 7) and control (CO, n = 5) groups to undergo 5-h daytime and night-time EMG measurements for three consecutive weeks. EMG electrodes were placed over the temporalis muscle on the habitual masticatory side. Those in the BF group underwent BF training to remind them of the occurrence of undesirable clenching activity when excessive EMG activity of certain burst duration was generated in week 2. Then, EMGs were recorded at week 3 as the post-BF test. Those in the CO group underwent EMG measurement without any EMG BF training throughout the study period. Although the number of tonic EMG events did not show statistically significant differences among weeks 1-3 in the CO group, events in weeks 2 and 3 decreased significantly compared with those in week 1, both daytime and night-time, in the BF group (P < 0·05, Scheffé's test). This study results suggest that EMG BF to improve AB tonic EMG events can also provide an effective approach to regulate SB tonic EMG events.

Chewing ability in an urban and rural population over 40 years in Shandong Province, China

Objectives

This study aimed to assess chewing ability related to dental status.

Material and methods

One thousand four hundred sixty-two Chinese subjects over 40 years, dentate in both jaws, were categorized in a hierarchical functional classification system with and without tooth replacements. Chewing ability was analyzed using multivariable logistic regression including five dental conditions (≥10 teeth in each jaw’; ‘complete anterior regions’; “sufficient premolar regions’ (≥3 posterior occluding pairs (POPs)); ‘sufficient molar regions’ (bilaterally ≥1 POP); and tooth replacement), adjusted for six background variables. Likelihood ratios for chewing problems were assessed at each level of the hierarchical classification system based on these dental conditions.

Results

Seventy-eight to 91 % of subjects reported no or minor chewing problems. The conditions ‘≥10 teeth in each jaw’, and ‘complete anterior regions’ were not associated, whereas ‘sufficient’ premolar regions’ and ‘sufficient molar regions’ were associated with chewing problems (Ors, 0.33–0.58). If classified hierarchically, the condition ‘≥10 teeth in each jaw’ was relevant for chewing problems (likelihood ratios 3.3–3.7). ‘Sufficient premolar region’ and ‘sufficient molar region’ were relevant to reduce the likelihood ratios for having chewing problems (both approximately with a factor 2), both for soft and for hard foods. Subjects with artificial teeth added had similar chance for chewing problems compared to counterparts with natural teeth only. However, if comparing replaced teeth with natural teeth, subjects with tooth replacement showed higher chance for chewing problems.

Conclusions

Chewing ability was strongly associated with dental conditions.

Clinical relevance

The presence of at least 10 teeth in each jaw had highest impact on chewing ability.

Is there an association between temporomandibular disorders and playing a musical instrument? A review of literature

Temporomandibular disorders (TMDs) have a multifactorial etiology. Among others, parafunctions and oral habits have been suggested as important initiating and perpetuating factors. Playing a musical instrument that loads the masticatory system, like wind instruments and the violin or viola, has been suggested to be part of this group of etiological factors. However, the evidence base for this suggestion is lacking. Therefore, the aim of this study was to review the literature on the possible association between playing a musical instrument and developing and/or having a TMD. A PubMed search, using the query ['Music'(Mesh) AND 'Craniomandibular Disorders'(Mesh)], yielded 19 articles, 14 of which were included in this review. Six of 14 papers had a case-control or pre-test-post-test design; the remaining eight papers were case reports of expert opinions. The former papers were analysed and tabulated according to the PICO (Patient/population-Intervention-Control/comparison-Outcome/results) system; the latter ones were only summarised and tabulated. All articles with a case-control or pre-test-post-test design suggested a possible association between TMD and playing a musical instrument, especially the violin and viola. However, no clear-cut conclusion could be drawn as to whether playing a musical instrument is directly associated with TMD, or only in combination with other factors. More and better research on this topic is needed, as to enable a better counselling and possibly even a better treatment of the suffering musician.

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.

Establishing better biological models to understand occlusion. I: TM joint anatomic relationships

Belief in and rejection of a relationship of occlusion and temporomandibular joint (TMJ) condyle-fossa position with normal and abnormal function are still contentious issues. Clinical opinions can be strong, but support in most published data (mostly univariate) is problematic. Distribution overlap, low sensitivity and specificity are a common basis to reject any useful prediction value. Notwithstanding, a relationship of form with function is a basic tenet of biology. These are multifactor problems, but the questions mostly have not been analysed as such. This review moves the question forward by focusing on TM joint anatomic organisation as the multifactor system it is expected to be in a closed system like a synovial joint. Multifactor analysis allows the data to speak for itself and reduces bias. Classification tree analysis revealed useful prediction values and usable clinical models which are illustrated, backed up by stepwise logistic regression. Explained variance, R(2), predicting normals from pooled TMJ patients was 32·6%, sensitivity 67·9%, specificity 85·7%; 37% versus disc displacement with reduction; and 28·8% versus disc displacement without reduction. Significant osseous organisational differences between TM joints with clicking and locking suggest that this is not necessarily a single disease continuum. However, a subset of joints with clicking contained characteristics of joints with locking that might contribute to symptom progression versus resistance. Moderately strong models confirm there is a relationship between TMJ osseous organisation and function, but it should not be overstated. More than one model of normals and of TM derangement organisation is revealed. The implications to clinical decision-making are discussed.

Digital Evaluation of Functional Occlusion Parameters and their Association with Temporomandibular Disorders

CONTEXT

Dental researchers are contradictory in their opinion on the role of occlusion in TMD. Occlusal evaluation of both conventional and digital methods in TMD patients will provide the accurate information about the factors accountable for occlusal instability. Identifying the factors responsible will facilitate precise diagnosis and treatment for TMD.

AIM

The AIM of the study was to determine the dynamic occlusal parameters strongly associated with the etiology of Temporomandibular disorders.

MATERIAL AND METHODS

Study group consisted of 100 patients; it included 50 patients with normal TMJ(Group I) and remaining 50 patients had a minimum of one positive sign or symptom of Temporomandibular disorder (GroupII). The patient's dynamic occlusal contacts were evaluated by both conventional and digital methods. The Articulating paper was utilized for conventional occlusion analysis. During conventional analysis centric, lateral and protrusive interferences were evaluated along with loss of vertical dimension. Digital occlusal analysis was performed with T-Scan III. Clusion time, disclusion times were recorded for both groups. Chi-square and Student't' statistical analyses were performed to ascertain the association and statistically significant difference between the groups using SPSS19.

RESULTS

Group II patients predominantly (66%)had Group-function occlusion compared to Group I subject. Centric slide more than 2 mm found to have strong influence (p value 0.008) on the etiology of TMD. Among the occlusal interferences evaluated balanced side interferences had a strong correlation with TMD with p-value of 0.003. Working side interferences, protrusive interferences had a p-value of 0.157, 0.826 respectively, indicating weak association. T-Scan analysis showed Group I had 0.689, 0.9136, 0.7952, 0.9794 seconds of clusion, left, right, protrusive disclusion time respectively compared to corresponding 1.862, 1.7995, 1.6978, 1.9296 seconds for Group II. Statistically significant difference (p≤0.05) was found between the mean values of both groups.

CONCLUSION

Among the dynamic occlusal parameters evaluated centric slide and balancing side interferences were found to be highly influential in TMD etiology. TMD patients had prolonged clusion and disclusion times compared to healthy TMJ patients.

A digital process for additive manufacturing of occlusal splints: a clinical pilot study

The aim of this study was to develop and evaluate a digital process for manufacturing of occlusal splints. An alginate impression was taken from the upper and lower jaws of a patient with temporomandibular disorder owing to cross bite and wear of the teeth, and then digitized using a table laser scanner. The scanned model was repaired using the 3Data Expert software, and a splint was designed with the Viscam RP software. A splint was manufactured from a biocompatible liquid photopolymer by stereolithography. The system employed in the process was SLA 350. The splint was worn nightly for six months. The patient adapted to the splint well and found it comfortable to use. The splint relieved tension in the patient's bite muscles. No sign of tooth wear or significant splint wear was detected after six months of testing. Modern digital technology enables us to manufacture clinically functional occlusal splints, which might reduce costs, dental technician working time and chair-side time. Maximum-dimensional errors of approximately 1 mm were found at thin walls and sharp corners of the splint when compared with the digital model.

Satisfaction with the dentition related to dental functional status and tooth replacement in an adult Bulgarian population: a cross-sectional study

OBJECTIVES

The purpose of this study is to assess satisfaction with the dentition in general, dental esthetics, and chewing function related to dental functional status and tooth replacement in subjects, dentate in both jaws.

MATERIALS AND METHODS

Dentitions of subjects (n = 2,437) aged ≥20 years were categorized in a hierarchical functional classification system, with and without tooth replacements, according to four dental conditions: '≥10 teeth in each jaw', 'complete anterior regions', 'sufficient premolar regions' (≥3 occluding pairs), and 'sufficient molar regions' (bilaterally ≥1 occluding pair). Likelihood ratios (LR) were used to express the ability of these conditions to discriminate between satisfied and not satisfied subjects. Odds ratios (OR) were calculated to evaluate associations between satisfaction, the four dental conditions separately, and tooth replacement.

RESULTS

In the hierarchical system, subjects having '<10 teeth' were more likely of being not satisfied with their dentitions (LR 4.09), esthetics (LR 3.51), and chewing (LR 5.49). As a separate condition, '≥10 teeth' was significantly associated only with satisfaction with chewing. The conditions 'complete anterior regions' and 'sufficient' premolar and molar regions' were associated with all satisfaction variables (ORs 1.47-2.96, p values ≤0.012). When dental conditions were determined on the basis of natural teeth only, having teeth replaced was positively correlated with satisfaction; when determined on the basis of natural plus replaced teeth, subjects having teeth replaced tended to be less satisfied than their counterparts with natural teeth only.

CONCLUSIONS

Satisfaction was strongly associated with dental functional status.

CLINICAL RELEVANCE

Dental configurations comprising both natural and artificial teeth were less likely to provide the same level of satisfaction as equivalent dental configurations comprising natural teeth only.

Oral tori are associated with local mechanical and systemic factors: a case-control study

PURPOSE

To estimate if various dental factors, medications, and medical conditions are associated with an increased risk for the presence of oral tori.

MATERIALS AND METHODS

Using a case-control study design, the investigators identified and adjudicated a sample of cases with torus palatinus (TP) and/or torus mandibularis (TM) during a 1.5-year period. The medical records were abstracted and data on dental factors, temporomandibular dysfunction (TMD), medications, and medical conditions were recorded. Risk estimates were calculated as adjusted odds ratios (AORs) with 95% confidence intervals (CIs) using conditional logistic regression analyses, and the P value was set at .05.

RESULTS

The sample was composed of 66 subjects with TM, 34 subjects with TP, and 100 control subjects from the same database. Any form of oral torus (TP and/or TM) was associated significantly with TMD (AOR, 10.51; 95% CI, 4.46 to 24.78; P<.01) and tooth attrition (AOR, 5.22; 95% CI, 2.32 to 11.77; P<.01). TP was associated significantly with TMD (AOR, 4.14; 95% CI, 1.21 to 14.21; P<.05), tooth attrition (AOR, 38.18; 95% CI, 7.20 to 202.41; P<.01), and treated hypertension (AOR, 6.64; 95% CI, 1.31 to 33.57; P<.05). TM was associated significantly with TMD (AOR, 5.77; 95% CI, 2.38 to 13.98; P<.01), tooth attrition (AOR, 6.69; 95% CI, 2.78 to 16.14; P<.01), and a penicillin allergy (AOR, 4.45; 95% CI, 1.05 to 18.83; P<.05).

CONCLUSIONS

This study provides clinical evidence showing significant associations between oral tori and various dental factors, medications, and medical conditions. These findings add to the list of environmental factors believed to contribute to the formation of oral tori.

The dental occlusion as a suspected cause for TMDs: epidemiological and etiological considerations

The relationship between the dental occlusion and temporomandibular disorders (TMDs) has been one of the most controversial topics in the dental community. In a large epidemiological cross-sectional survey - the Study of Health in Pomerania (Germany) - associations between 15 occlusion-related variables and TMD signs or symptoms were found. In other investigations, additional occlusal variables were identified. However, statistical associations do not prove causality. By using Hill's nine criteria of causation, it becomes apparent that the evidence of a causal relationship is weak. Only bruxism, loss of posterior support and unilateral posterior crossbite show some consistency across studies. On the other hand, several reported occlusal features appear to be the consequence of TMDs, not their cause. Above all, however, biological plausibility for an occlusal aetiology is often difficult to establish, because TMDs are much more common among women than men. Symptom improvement after insertion of an oral splint or after occlusal adjustment does not prove an occlusal aetiology either, because the amelioration may be due to the change of the appliance-induced intermaxillary relationship. In addition, symptoms often abate even in the absence of therapy. Although patients with a TMD history might have a specific risk for developing TMD signs, it appears more rewarding to focus on non-occlusal features that are known to have a potential for the predisposition, initiation or perpetuation of TMDs.

Review of aetiological concepts of temporomandibular pain disorders: towards a biopsychosocial model for integration of physical disorder factors with psychological and psychosocial illness impact factors

Several studies have reported that musculoskeletal disorders of the stomatognathic system, commonly known as temporomandibular disorders (TMD) resemble musculoskeletal disorders and chronic pain disorders in general. There is also general consensus that combined biomedical and biopsychosocial methods best support the assessment and management of the cardinal features of TMD, i.e., pain and dysfunction or physical (peripheral) and psychosocial (central) factors. This overview of the aetiology of TMD will outline conceptualizations of past models and present the current view that patients with TMD should be assessed according to both the physical disorder and the psychosocial illness impact factors. The conceptual theories outlined in this review include biomedical models related to temporomandibular joints, muscles of mastication and occlusal factors, psychological models and the biopsychosocial models. An integrated and multidimensional approach concerning physical and psychosocial factors in temporomandibular pain and dysfunction is presented as an example of how the biopsychosocial model and information processing theory may apply in the conceptualization and management of TMD for various health care professionals.

Intraoral myofascial therapy for chronic myogenous temporomandibular disorder: a randomized controlled trial

OBJECTIVE

Studies investigating the efficacy of intraoral myofascial therapies (IMTs) for chronic temporomandibular disorder (TMD) are rare. The present study was an expansion of a previously published pilot study that investigated whether chiropractic IMT and the addition of education and self-care were superior to no-treatment or IMT alone for 5 outcome measures-interincisal opening range, jaw pain at rest, jaw pain upon opening, jaw pain upon clenching, and global reporting of change-over the course of 1 year.

METHODS

Ninety-three participants with myogenous TMD between the ages of 18 and 50 years experiencing chronic jaw pain of longer than 3 months in duration were recruited for the study. Successful applicants were randomized into 1 of 3 groups: (1) IMT consisting of 2 treatment interventions per week for 5 weeks, (2) IMT plus education and "self-care" exercises (IMTESC), and (3) wait-list control. The main outcome measures were used. Range of motion findings were measured by vernier callipers in millimeters, and pain scores were quantified using an 11-point self-reported graded chronic pain scale. Global reporting of change was a 7-point self-reported scale, balanced positively and negatively around a zero midpoint.

RESULTS

There were statistically significant differences in resting, opening and clenching pain, opening scores, and global reporting of change (P < .05) in both treatment groups compared with the controls at 6 months and 1 year. There were also significant differences between the 2 treatment groups at 1 year.

CONCLUSIONS

The study suggests that both chiropractic IMT and IMTESC were superior to no-treatment of chronic myogenous TMD over the course of 1 year, with IMTESC also being superior to IMT at 1 year.

Condylar shape in relation to anterior disk displacement in juvenile females

The purpose of the study was to test the hypothesis that condylar shape varies based upon the condition of anterior disk displacement in young adolescent patients with temporomandibular disorder (TMD). The study design consisted of 96 juvenile female patients (aged 9 to 20; 15.1 +/- 2.3 yrs.) with clinical signs and/or symptoms of TMD. Bilateral high-resolution magnetic resonance imaging scans were performed in frontal and horizontal views with the mandible in the closed position. Disk positions were evaluated to classify the patients into three diagnostic groups. The results of the study, using ANOVA and Bonferroni tests, demonstrated significant differences among the groups. The conclusion drawn from the study was that condylar shape and size vary based on anterior disk position in juvenile females with TMD. The study's results suggest that disk displacement results in a smaller condyle.

Termo do 1º Consenso em Disfunção Temporomandibular e Dor Orofacial

O Termo do 1º Consenso em Disfunção Temporomandibular e Dor Orofacial* foi criado com o propósito de substituir divergências por evidência científica dentro dessa especialidade da Odontologia. O documento oferece informações claras e fundamentadas para orientar o cirurgião-dentista e demais profissionais de saúde sobre os cuidados demandados pelo paciente, tanto no processo de diagnóstico diferencial quanto na fase de aplicação das terapias de controle da dor e disfunção. O Termo foi aprovado no mês de janeiro de 2010 em reunião realizada durante o Congresso Internacional de Odontologia do Estado de São Paulo e converge o pensamento dos profissionais mais conceituados do Brasil na especialidade Disfunção Temporomandibular e Dor Orofacial.

The prevalence of clinical diagnostic groups in patients with temporomandibular disorders

The aim of this study was to observe the prevalence of diagnostic groups of temporomandibular disorders (TMD) in patients who were referred or sought treatment for TMD and/or orofacial pain in a private clinic. The clinical records of 357 patients were evaluated and selected based on inclusion/exclusion criteria; the mean age was 32 years. A clinical examination was performed and the diagnosis was based on the American Academy of Orofacial Pain criteria. Results showed that 86.8% of patients were women and 93.3% of the patients presented more than one diagnosis. The most frequent chief complaint (n = 216, chi2 = 30.68, p = 0.001) and total diagnosis realized (n = 748, chi2 = 14.14, p = 0.001) were muscle related. We concluded that women seek treatment for dysfunction/disorders of orofacial structures more than men do; patients seeking specialized treatment have more than one diagnosis and muscle dysfunction is more prevalent than intra-articular disorders.

Missing posterior teeth and risk of temporomandibular disorders

There is disagreement about the association between missing posterior teeth and the presence of temporomandibular disorders (TMD). Here, the purpose was to investigate whether the number of missing posterior teeth, their distribution, age, and gender are associated with TMD. Seven hundred and forty-one individuals, aged 21-60 years, with missing posterior teeth, 386 with and 355 without TMD, were included. Four variables-gender, age, the number of missing posterior teeth, and the number of dental quadrants with missing posterior teeth-were analyzed with a logistic regression model. All four variables-gender (OR = 1.59, men = 1, women = 2), age (OR = 0.98), the number of missing posterior teeth (OR = 0.51), and the number of dental quadrants with missing posterior teeth (OR = 7.71)-were entered into the logistic model (P < 0.01). The results indicate that individuals who lose posterior teeth, with fewer missing posterior teeth but in more quadrants, have a higher prevalence of TMD, especially young women.

Comparison of increased overjet cases and controls: normative data for condylar positions

The aim was to compare normal overjet versus large overjet cases with clinically healthy temporomandibular joints (TMJ); to establish normative data regarding the difference between condylar positions in centric occlusion (CO) and maximum intercuspation (MI) and deflective CO contacts. Two study groups of normal overjet and large overjet cases consisted each of 33 subjects with no detectable clinical signs of temporomandibular disorder (TMD). CO-MI differences were recorded using the SAM Mandibular Position Indicator. Deflective contacts were examined on models mounted in CO. There was a significant difference between groups in the vertical (P = 0.030) and transverse (P = 0.008) range of movement from CO to MI, but not in the antero-posterior direction. There were no differences in the location of deflective contacts. Results of this study showed that patients with increased overjet show some differences compared with normal overjet patients, even in the non-patients. Further research on TMD patients is needed to find out about the role these features play in the aetiology and treatment of temporomandibular disorder (TMD). This study indicates that the clinician should be paying special attention to the TMJ status of patients with a large overjet.

Association between anterior tooth wear and temporomandibular disorder pain in a German population

STATEMENT OF PROBLEM

Bruxism is purported to be a risk factor for temporomandibular disorder (TMD) pain, but the association requires clarification.

PURPOSE

The purpose of this study was to investigate the relation between anterior tooth wear as an indicator for bruxism and the presence of TMD pain.

MATERIAL AND METHODS

Study subjects included 646 participants (age range 35 to 44 years) of a national oral health survey in Germany. Anterior tooth wear was registered for each anterior tooth with a 4-point scale (none, mild, moderate, and severe wear). Temporomandibular disorder was defined as self-reported pain in the face, jaw muscles, and/or temporomandibular joint (TMJ) during the last month, according to either the German version of the Research Diagnostic Criteria for Temporomandibular Disorders or the response to a question about pain in the masticatory muscles or the TMJ according to the Helkimo-Index. A multiple logistic regression analysis, controlling for the effects of age and gender, investigated the linear relationship between increased tooth wear and the risk of TMD pain.

RESULTS

After adjusting for age and gender, an odds ratio of 1.11 (95% confidence interval: 0.7-1.8) indicated that the risk of TMD pain increased an estimated 11% per unit increase of tooth wear. There was no statistically significant or clinically relevant relationship between a linear increase of tooth wear and risk of TMD pain.

CONCLUSION

Anterior tooth wear was not associated with self-reported TMD pain in 35- to 44-year-old subjects. Using anterior tooth wear as an indicator for long-term bruxing behavior, a clinically relevant dose-response relationship between this type of bruxism and TMD pain does not appear to exist.

The prevalence of myofascial pain and its association with occlusal factors in a threshold country non-patient population

The objective of the study is to assess the prevalence of myofascial pain in a threshold country and to isolate occlusal risk factors. One hundred and seventy-one randomized selected women were examined by a trained examiner in accordance with the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) examination procedure. Subscales of the SCL 90-R, graded chronic pain status, and anamnestic questionnaires were also used. Logistic regression was performed to compute the odds ratios for six common occlusal features with regard to the presence of myofascial pain, in accordance with the RDC/TMD criteria. Fifteen subjects (15 / 151 = 9.93%) suffered from myofascial pain. Results from logistic regression analysis showed that non-occlusion (posterior teeth, at least one side) and open bite increased the risk of myofascial pain. The prevalence of myofascial pain in this study is comparable with that in another study, in a highly industrialized environment, in which the RDC/TMD was used. The role of occlusion in a non-patient population seems to be restricted to serious alterations of normality. This article presents the prevalence of myofascial pain and its association with occlusal factors. This issue will help the clinicians to assess the influence of occlusion in myofascial pain patients and to send the patient to the appropriate specialist.

A comparison of regression trees, logistic regression, generalized additive models, and multivariate adaptive regression splines for predicting AMI mortality

Clinicians and health service researchers are frequently interested in predicting patient-specific probabilities of adverse events (e.g. death, disease recurrence, post-operative complications, hospital readmission). There is an increasing interest in the use of classification and regression trees (CART) for predicting outcomes in clinical studies. We compared the predictive accuracy of logistic regression with that of regression trees for predicting mortality after hospitalization with an acute myocardial infarction (AMI). We also examined the predictive ability of two other types of data-driven models: generalized additive models (GAMs) and multivariate adaptive regression splines (MARS). We used data on 9484 patients admitted to hospital with an AMI in Ontario. We used repeated split-sample validation: the data were randomly divided into derivation and validation samples. Predictive models were estimated using the derivation sample and the predictive accuracy of the resultant model was assessed using the area under the receiver operating characteristic (ROC) curve in the validation sample. This process was repeated 1000 times-the initial data set was randomly divided into derivation and validation samples 1000 times, and the predictive accuracy of each method was assessed each time. The mean ROC curve area for the regression tree models in the 1000 derivation samples was 0.762, while the mean ROC curve area of a simple logistic regression model was 0.845. The mean ROC curve areas for the other methods ranged from a low of 0.831 to a high of 0.851. Our study shows that regression trees do not perform as well as logistic regression for predicting mortality following AMI. However, the logistic regression model had performance comparable to that of more flexible, data-driven models such as GAMs and MARS.

Importance of occlusion aspects in the completion of orthodontic treatment

The purpose of this study was to address the therapeutic goals regarding the static and functional occlusion in the completion of orthodontic treatment. For such purpose, a study population comprising 20 female treated Class II malocclusion subjects with an initial mean age of 11 years underwent a two-phase treatment (orthopedics and orthodontics). The patients were diagnosed in centric relation and were treated according to the six keys for normal occlusion and functional occlusal parameters (centric relation, vertical dimension, lateral and anterior guidances, occlusal contacts and direction of forces applied on the teeth). After removal of fixed mechanics, retainers were installed and maintained for two years. Five years after orthodontic completion, the occlusal stability of the patients was evaluated regarding molar relationship and overjet, measured in dental casts. All subjects maintained the normal molar relationship and correct overjet achieved at the end of treatment, indicating a fair level of occlusal stability. The importance of the criteria of the ideal functional occlusion to ensure a better stability after completion orthodontic treatment will be discussed in detail in this paper. In addition, some clinical situations in which localized adjustments are indicated for occlusal refinement will be described.

Dental attrition models predicting temporomandibular joint disease or masticatory muscle pain versus asymptomatic controls

AIMS

To determine whether patients with temporomandibular joint disease or masticatory muscle pain can be usefully differentiated from asymptomatic controls using multifactorial classification tree models of attrition severity and/or rates.

METHODS

Measures of attrition severity and rates in patients diagnosed with disc displacement (n = 52), osteoarthrosis (n = 74), or masticatory muscle pain only (n = 43) were compared against those in asymptomatic controls (n = 132). Cross-validated classification tree models were tested for fit with sensitivity, specificity, accuracy and log likelihood accountability.

RESULTS

The model for identifying asymptomatic controls only required the three measures of attrition severity (anterior, mediotrusive and laterotrusive posterior) to be differentiated from the patients with a 74.2 +/- 3.8% cross-validation accuracy. This compared with cross-validation accuracies of 69.7 +/- 3.7% for differentiating disc displacement using anterior and laterotrusive attrition severity, 68.7 +/- 3.9% for differentiating disc displacement using anterior and laterotrusive attrition rates, 70.9 +/- 3.3% for differentiating osteoarthrosis using anterior attrition severity and rates, 94.6 +/- 2.1% for differentiating myofascial pain using mediotrusive and laterotrusive attrition severity, and 92.0 +/- 2.1% for differentiating myofascial pain using mediotrusive and anterior attrition rates. The myofascial pain models exceeded the > or =75% sensitivity and > or =90% specificity thresholds recommended for diagnostic tests, and the asymptomatic control model approached these thresholds.

CONCLUSION

Multifactorial models using attrition severity and rates may differentiate masticatory muscle pain patients from asymptomatic controls, and have some predictive value for differentiating intracapsular temporomandibular disorder patients as well.

Relationship between tooth contacts in the retruded contact position and mandibular positioning during retrusion

We conducted a series of studies with the purpose to investigate the locations of tooth contacts in the retruded contact position (RCP) and to discuss their significance in the stomatognathic system. In the present study, the relationship between the locations of RCP contacts and mandibular positioning during retrusion was examined. Thirty dentists and clinical residents were selected as subjects. One specialist in prosthetic dentistry examined each subject for the location of the RCP contacts. The mandibular positioning during retrusion was measured using a mandibular movement analysis system with six degrees of freedom. Originally programmed software was developed. Five reference points were selected: the central lower incisor (point I), the first molars on both sides (points RM and LM) and the condyles on both sides (points RC and LC). Tooth contact was observed most frequently at the second molar, followed by the first premolar. Points I, RM and LM all moved in an inferior-posterior direction, whereas points RC and LC moved in various directions ranging from superior-posterior to inferior-posterior. When the subjects were divided into two groups according to the most anterior tooth of occlusion in the RCP, the condylar positioning tended to be more superior in the group with molar contact than that with premolar contact. These results suggest that the locations of RCP contacts could be an important factor in jaw guidance during retrusion.