Stable cranial parameters to evaluate the occlusal plane orientation in the frontal plane: a systematic review.

INTRODUCTION: A systematic review of the literature available up to October 2020 has been conducted to determine which cranial plane could represent a stable and reliable parameter to evaluate the orientation of the occlusal plane in a frontal view. EVIDENCE ACQUISITION: An electronic research was performed across the following electronic databases: PUBMED, EBSCO, SCOPUS, WoS, COCHRANE LIBRARY, SciELO, EMBASE and GOOGLE SCHOLAR. Observational studies based on imaging and anthropometry were identified, and all languages have been included. The articles were selected and analyzed by three authors independently. PICO format was adopted to analyze the studies and AXIS guidelines were used to assess the quality of evidence. EVIDENCE SYNTHESIS: We found eleven articles eligible for full-text analysis. All studies included only young subjects and analyzed the occlusal plane in relation to the frontal plane traced between the right and left tragus (Camper's and Frankfurt planes), to the interpupillary plane, and to other soft and hard tissues references. The outcomes of selected studies were various, with a low quality of evidence, and they did not allow to infer a stable cranial relation between the occlusal plane and other bone structures. CONCLUSIONS: The evidence does not support that the interpupillary plane represent a reliable parameter to evaluate the occlusal plane orientation in a frontal view; instead, the Frankfurt plane could be a much more stable reference parameter, from a morphological perspective. It is necessary to perform an observational study upon craniums to define which are the most stable cranial reference planes to determine the orientation of the occlusal plane in dentate subjects.

Prediction methods of maxillary canine impaction: a systematic review.

OBJECTIVE: To describe and assess the available evidence of prediction methods of maxillary canine impaction (MCI). MATERIAL AND METHODS: A systematic search was conducted through PubMed, Cochrane Library, Embase, EBSCOhost, Scopus, ScienceDirect, Bireme and Scielo until December 2020. This systematic review was conducted according to the PRISMA statement. The methodology of the selected studies was assessed using the Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS-2). RESULTS: A total of 2391 articles were identified in the first approach and after a 2-phase selection, 11 studies were included in qualitative analysis. Prediction methods were constructed using equation-based models, geometric measurements and computational methods from clinical and imaging data to predict palatal/buccal MCI. The quality of evidence was low to moderate due to the presence of risk of bias in most of the studies included. Three cohort studies with the best methodological quality proposed prediction models based on geometric measurements, canine position and facial growth pattern that would allow predicting MCI from CBCT, lateral and panoramic radiographs. CONCLUSIONS: The evidence is limited and most of the studies present a low methodological quality. However, it is possible to suggest that some prediction methods based on the position of the canine and facial growth pattern could predict palatal/buccal MCI in mixed dentition. Cohort studies with better methodological quality and long-term follow-up are needed to better validate a prediction model.

Micromotion analysis of immediately loaded implants with Titanium and Cobalt-Chrome superstructures. 3D finite element analysis.

OBJECTIVE: The aim of this study was to evaluate the amount of micromotion of dental implants under immediate loading supported by Titanium (Ti) and Cobalt-Chrome (Co-Cr) superstructures. MATERIAL AND METHODS: A model of tridimensional half-edentulous maxilla with three dental implants was made using the Finite Element Analysis (FEA). Two standard and one zygomatic implants were connected to a superstructure with an elliptic section of 6x 3 mm (mm). Two study models were established. Model A: Titanium (Ti) alloy superstructure; Model B: Cobalt-Chrome (Co-Cr) alloy superstructure. To simulate an immediate-loading situation, a friction coefficient of 0.71 was applied between the implant and the bone surface. An axial load of 252.04 [N] was applied on standard and zygomatic implants. RESULTS: The Micromotion of dental implants was similar in both superstructure situations. The amount of micromotion was slightly higher in B1 and B3 models (Co-Cr alloy-superstructure) compared with A1 and A3 models (Titanium alloy superstructure). The micromotion values in two groups were greater than 150 µm in the incisive region (standard implant) and molar region (zygomatic). In general, the micromotion was higher on the implant that received the load with respect to the other implants. The greater difference was observed when the load was applied on the standard implant A1 (Model A1 = 189.12 µm) compared with standard implant B1(Model B1 = 263.25 µm). CONCLUSIONS: Within the limits of present study, all implants on different load application points showed micromotion; in general, the amount of micromotion was slightly higher in the implants connected with Co-Cr alloy superstructure.

Craniofacial growth predictors for class II and III malocclusions: A systematic review.

OBJECTIVE: To evaluate the validity of craniofacial growth predictors in class II and III malocclusion. MATERIAL AND METHODS: An electronic search was conducted until August 2020 in PubMed, Cochrane Library, Embase, EBSCOhost, ScienceDirect, Scopus, Bireme, Lilacs and Scielo including all languages. The articles were selected and analyzed by two authors independently and the selected studies was assessed using the 14-item Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS-2). The quality of evidence and strength of recommendation was assessed by the GRADE tool. RESULTS: In a selection process of two phases, 10 articles were included. The studies were grouped according to malocclusion growth predictor in (1) class II (n = 4); (2) class III (n = 5) and (3) class II and III (n = 1). The predictors were mainly based on data extracted from cephalometries and characterized by: equations, structural analysis, techniques and computer programs among others. The analyzed studies were methodologically heterogeneous and had low to moderate quality. For class II malocclusion, the predictors proposed in the studies with the best methodological quality were based on mathematical models and the Fishman system of maturation assessment. For class III malocclusion, the Fishman system could provide adequate growth prediction for short- and long-term. CONCLUSIONS: Because of the heterogeneity of the design, methodology and the quality of the articles reviewed, it is not possible to establish only a growth prediction system for class II and III malocclusion. High-quality cohort studies are needed, well defined data extraction from cephalometries, radiographies and clinical characteristics are required to design a reliable predictor.

Evaluation of short-term effectiveness of orthopedic manual therapy in signs and symptoms of myofascial pain: a controlled clinical trial / Evaluación de la eficacia a corto plazo de la terapia manual ortopédica en signos y síntomas de dolor miofascial: un ensayo clínico controlado

To evaluate the short-term effectiveness of orthopedic manual therapy (OMT) in signs and symptoms of myofascial pain (MFP) in young adults. Materials and Methods: An experimental controlled clinical study was performed in young adults between 19 and 24 years old. Thirty-one patients with MFP according to Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were divided into two groups. Group A: Orthopedic Manual Therapy (n=16; 10 females, 6 males; 21.6 ± 1.70 years old), and Group B: Control group (n=15; 10 females, 5 males; 20.9 ± 2.00 years old). The participants of group A were treated for a period of 6 weeks; Six therapeutic interventions were performed. Degree of dysfunction (Helkimo index), pain level (VAS scale), and range of mandibular movements (opening and lateral movements) were taken at baseline (T0) and immediately at post-treatment (T1). The data were analyzed with chi-square test and t-test; p<0.05 was considered significant. Result: After the OMT, there were no significant changes in diagnosis of MFP according to RDC/TMD (p=0.41); however, there was a statistically significant improvement in the Helkimo index (p=0.0083) and the level of pain according to the VAS scale (p=0.0004). Mandibular movements did not show significant differences (p>0.05). Conclusion: This study suggested that a 6-week period of OMT treatment has a clinically significant effect in pain level and degree of dysfunction in patients with MFP. A longer follow-up study is required to better assess the effects of manual therapy.

Evaluar la efectividad a corto plazo de la terapia manual ortopédica (TMO) en los signos y síntomas del dolor miofascial (DMF) en adultos jóvenes. Materiales and Métodos: Se realizó un estudio clínico controlado en adultos jóvenes entre 19 y 24 años. Treinta y un pacientes fueron diagnosticados con DMF según los criterios de diagnóstico para trastornos tempo-romandibulares (CDI/TTM) y se dividieron en dos grupos. Grupo A: Terapia manual ortopédica (n = 16; 10 mujeres, 6 hombres; 21,6 ± 1,70 años), y Grupo B: grupo de control (n = 15; 10 mujeres, 5 hombres; 20,9 ± 2,00 años). Los participantes del grupo A fueron tratados por un período de 6 semanas. Se realizaron seis intervenciones terapéuticas. El grado de disfunción (índice Helkimo), el nivel de dolor (escala EVA) y el rango de movimientos mandibulares (movimientos de apertura y laterales) se evaluaron al inicio del estudio (T0) e inmediatamente después del tratamiento (T1). Los datos se analizaron con la prueba de chi-cuadrado y la prueba t de student; se consideró significativo cuando p fue menor a 0.05. Resultados: Después de la TMO, no hubo cambios significativos en el diagnóstico de DMF según CDI /TTM (p=0,41); sin embargo, hubo una mejora estadísticamente significativa en el índice Helkimo (p=0.0083) y el nivel de dolor según la escala EVA (p= 0.0004). Los movimientos mandibulares no mostraron diferencias significativas (p>0.05). Conclusión: Este estudio sugirió que un período de 6 semanas de tratamiento con TMO tiene un efecto clínicamente significativo en el nivel de dolor y el grado de disfunción en pacientes con DMF. Se requiere un estudio de largo plazo para evaluar de mejor forma el efecto de la terapia manual ortopédica.

Temporomandibular disorders in growing patients after treatment of class II and III malocclusion with orthopaedic appliances: a systematic review.

OBJECTIVE: To determine if the use of orthopaedic appliances in growing patients applied to correct Class II and III malocclusion is related to the development of temporomandibular disorders (TMD). MATERIAL AND METHODS: A systematic review was conducted between 1960 and July 2017, based on electronic databases: PubMed, Cochrane Library, Embase, Medline, Scopus, EBSCOhost, Scielo, Lilacs and Bireme. Controlled clinical trials (CCTs) and randomized controlled trials (RCTs) were identified. The articles were selected and analyzed by two authors independently. The quality of the evidence was determined according to the guidelines of the Cochrane Risk Bias Assessment Tool and the Cochrane Quality Study Guide. RESULTS: Seven articles were included, four CCTs and three RCTs. The studies were grouped according to malocclusion treatment in (a) class II appliances (n = 4) and (b) class III appliances (n = 3). The quality of evidence was low due to the high risk of bias, independent of the association reported. All studies concluded that the use of orthopaedic appliances would not contribute to the development of TMD. CONCLUSIONS: The quality of evidence available is insufficient to establish definitive conclusions, since the studies were very heterogeneous and presented a high risk of bias. However, it is suggested that the use of orthopaedic appliances to correct class II and III malocclusion in growing patients would not be considered as a risk factor for the development of TMD. High-quality RCTs are required to draw any definitive conclusions.

Centric relation-intercuspal position discrepancy and its relationship with temporomandibular disorders. A systematic review.

OBJECTIVE: The objective of this study is to assess the relationship between centric relation-intercuspal position discrepancy (CR-ICP discrepancy) and temporomandibular disorders (TMDs), by systematically reviewing the literature. MATERIALS AND METHODS: A systematic research was performed between 1960 and 2016 based on electronic databases: PubMed, Cochrane Library, Medline, Embase, Scopus, EBSCOhost, BIREME, Lilacs and Scielo, including all languages. Analytical observational clinical studies were identified. Two independent authors selected the articles. PICO format was used to analyze the studies. The Newcastle-Ottawa Scale (NOS) was used to verify the quality of the evidence. RESULTS: Four hundred and sixty-seven potentially eligible articles were identified. Twenty studies were analyzed, being grouped according to intervention in studies in orthodontic patients (n = 3) and studies in subjects without intervention (n = 17). Quality of evidence was low, with an average score of 3.36 according to Newcastle-Ottawa Scale. In most studies, the presence of CR-ICP discrepancy is associated with the presence of muscle (pain) and joint disorders (noise, disc displacement, pain, crepitus, osteoarthritis and osteoarthrosis). However, the lack of consistency of the results reported reduces the validity of the studies making it impossible to draw any definite conclusions. CONCLUSIONS: Because of the heterogeneity of the design and methodology and the low quality of the articles reviewed, it is not possible to establish an association between CR-ICP discrepancy and TMD. The consequence of CR-ICP discrepancy on the presence of TMD requires further research, well-defined and validated diagnostic criteria and rigorous scientific methodologies. Longitudinal studies are needed to identify CR-ICP discrepancy as a possible risk factor for the presence of TMD.

Sleep and awake bruxism in adults and its relationship with temporomandibular disorders: A systematic review from 2003 to 2014.

OBJECTIVE: In order to establish a relationship between bruxism and temporomandibular disorders (TMDs), a systematic review was performed. MATERIALS AND METHODS: A systematic research was performed based on PubMed, Cochrane Library, Medline, Embase, BIREME, Lilacs and Scielo data bases, between 2003 and 2014 including all languages. Descriptive clinical cases were identified. Two independent authors selected the articles. PICO format was used to analyse the studies and the Newcastle-Ottawa Scale (NOS) was used to verify the quality of the evidence. RESULTS: Thirty-nine studies (n = 39) were analysed in this review. According to bruxism diagnosis, articles were grouped as follows: polysomnographic diagnosis (PSG) (n = 7), clinical diagnosis (n = 11) and survey/self-report (n = 21). Thirty-three articles (n = 33) established a positive relation between bruxism and TMD and six (n = 6) did not. Quality of evidence was low to moderate. In general, the most part of the studies showed shortcomings on their design with bias risk, and also had a low sensitivity on bruxism diagnosis. CONCLUSIONS: The evidence based on PSG was not as conclusive as the studies that used surveys and clinical exam to diagnosis bruxism, when bruxism was related to TMD. Sleep bruxism could be associated with myofascial pain, arthralgia and joint pathology as disc displacement and joint noises. Although the evidence at present is inconclusive and does not provide information according to the type of bruxism (bruxism sleep and wakefulness), it is possible to suggest that bruxism would be associated with TMD.

Patología temporomandibular asociada a masticación unilateral en adultos jóvenes / Temporomandibular disorders and its relationship with unilateral chewing in young adults

Objetivo El objetivo de este estudio fue determinar la relación entre el lado de masticación habitual y la presencia de trastornos temporomandibulares (TTM) en adultos jóvenes. Materiales y métodos Estudio analítico de casos y controles, ciego simple, en estudiantes adultos jóvenes de la Facultad de Odontología de la Universidad de Chile. La muestra consistió en 70 sujetos (22-26 años). Se utilizó el ángulo funcional masticatorio (AFM) para definir el lado de masticación habitual y el RDC/TMD para determinar el tipo de TTM y el lado con mayor prevalencia. Se aplicó el test de Chi-cuadrado y el test exacto de Fisher (IC 95%). Resultados Un total de 56 sujetos (80,0%) fueron masticadores unilaterales y 14 (20,0%) masticadores bilaterales. En 34 sujetos (48,6%) se diagnosticó patología según RDC/TMD, mientras que en 36 individuos (51,4%) no se evidenció TTM. No hubo diferencia respecto al lado de masticación y presencia de TTM (p = 0,63). Se observó una alta tendencia entre la masticación unilateral y presencia de patología articular (grupos II y III, RDC/TMD) (p = 0,06). Conclusión A pesar de observarse una alta tendencia entre masticación unilateral y patología articular, la relación entre tipo de masticación y TTM no ha podido establecerse. Si bien tampoco se encontró diferencia significativa entre lado de masticación y su coincidencia con el lado de la patología, esto podría ser por la diversidad de factores implicados en los TTM.

Objective The aim of this study was to determine the relationship between the habitual chewing side and the presence of temporomandibular disorders (TMD) in young adults. Materials and methods An analytical case-control and simple blind study was performed on 70 young adult subjects (22-26 years) from the Faculty of Dentistry of the University of Chile. The masticatory functional angle (MFA) was used to determine the habitual chewing side in all subjects, as well as applying the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) in order to determine the type of TMD and the most prevalent side. Data were analysed using Chi squared test and Fisher's exact test (95% CI). Results A total of 56 subjects (80.0%) were unilateral chewers and 14 (20.0%) were bilateral chewers. A diagnosis of TMD was made in 34 (48.6%) subjects according to RDC/TMD, while 36 individuals (51.4%) showed no evidence of any disorder. There were no differences between unilateral chewing and the presence of TMD (p=0.63). There was a high trend between unilateral chewing and presence of joint disease (groups II and III, RDC/TMD) (p=0.06). Conclusion Despite a high trend between unilateral chewing and joint disease observed, the relationship between the type of chewing and TMD has not been established. No relationship was found between the chewing side and its coincidence with the disease side. This could be because of the different factors involved in TMD.