Effect of the timing of radiation therapy on the push-out strength of resin cement to root dentine.

This study investigated the effect of radiation timing on the bond strength of resin cement to intraradicular dentine. Fifty human teeth were distributed into 5 groups (n = 10): Control (nonirradiated teeth), Before-RCT (teeth irradiated before root canal treatment), After-CH (teeth irradiated after canal preparation and placement of calcium hydroxide intracanal dressing), After-RCT (teeth irradiated after completion of root canal treatment) and After-FPL (teeth irradiated after luting of a glass fibre post). Each tooth received 70 Gy irradiation. The roots were sectioned for push-out strength testing. After-RCT and After-FPL groups had significantly lower push-out strength than the control at the middle third (p < 0.05). Control and After-CH groups had a higher percentage of cohesive dentine failure. Radiotherapy after root canal obturation and post luting adversely affected the adhesiveness of resin cement to intraradicular dentine. Teeth irradiated before root canal treatment and after placement of calcium hydroxide had the best performance.

Three-dimensional skeletal and dentoalveolar sagittal and vertical changes associated with cantilever Herbst appliance in prepubertal patients with Class II malocclusion.

INTRODUCTION: This study aimed to assess sagittal and vertical skeletal and dentoalveolar changes through the use of 3-dimensional imaging in prepubertal Class II malocclusion patients treated with a cantilever Herbst appliance (HA). Condyle-glenoid fossa positional changes were also quantified. METHODS: This retrospective cohort study assessed 22 children (11.2 years ± 1.2) consecutively treated with a cantilever HA for 12 months and 11 untreated children (aged 9.3 ± 0.30 years) that served as controls. Cone-beam computed tomography was performed at baseline (T1) and at the end of the observation period (T2). Movements in the regions of interest were measured as linear displacements from cone-beam computed tomography images through algebraic calculations. A Student t test for independent samples was used for group equivalence testing at T1, and the treatment differences between T2 and T1 were evaluated by 2 analyses of covariance, one considering the expected growth unit as a covariate and the other with an annualized factor. RESULTS: The largest dental movement was a mesial movement of mandibular molars (3.70 mm), whereas the largest skeletal changes consisted of a larger relative length of the mandible (difference of 1.2 mm) in the HA group than in the control group. CONCLUSIONS: Within the study limitations (retrospective cohort, historical control group, and sample size), 3-dimensional imaging suggests that HA corrected Class II malocclusion in a predominantly prepubertal sample through more dental than skeletal changes. The changes were more significant in the sagittal than in the vertical direction. In addition, relative stability in the condyle-fossa relationship was noted.

Association between Orthodontic Force and Dental Pulp Changes: A Systematic Review of Clinical and Radiographic Outcomes.

INTRODUCTION: Orthodontic force triggers a sequence of biological responses that can affect dental pulp. The aim of this study was to systematically evaluate the clinical and radiographic findings of orthodontic force application on dental pulp. METHODS: Two reviewers comprehensively and systematically searched 6 electronic databases (Latin American and Caribbean Health Sciences [LILACS], Embase, Cochrane Library, MEDLINE/PubMed, Scopus, and Web of Science) and the gray literature (Google Scholar, OpenGrey, and ProQuest) until April 2021. According to the PICOS criteria, randomized clinical trials and observational studies that evaluated clinical or radiographic findings compatible with dental pulp changes due to orthodontic force were included. Studies in open apex or traumatized teeth, case series or reports, and laboratory-based or animal studies were excluded. The Newcastle-Ottawa Scale and Cochrane Risk of Bias 2.0 tool were used to determine the risk of bias assessment. The overall certainty level was evaluated with the Grading of Recommendations, Assessment, Development and Evaluations tool. RESULTS: Twenty-six studies were included. Among the clinical findings, orthodontic force promoted an increased pulp sensibility response and decreased pulp blood flow. Changes in pulp cavity volume and increased incidence of pulp stones were the radiographic findings observed. The studies presented a moderate risk of bias for most of the domains. The certainty of the evidence was considered very low. CONCLUSIONS: Orthodontic force promoted changes in the dental pulp, generating clinical and radiographic findings. It is crucial to know these changes so that orthodontic mechanics can be safely performed. The clinician has effective noninvasive methods to assess the health and possible pulp changes during orthodontic treatment.

Effect of orthodontic force on dental pulp histomorphology and tissue factor expression.

OBJECTIVES: To evaluate the effects of orthodontic force on histomorphology and tissue factor expression in the dental pulp. MATERIALS AND METHODS: Two reviewers comprehensively and systematically searched the literature in the following databases: Latin American and Caribbean Health Sciences, Embase, Cochrane, PubMed, Scopus, Web of Science, and Grey literature (Google Scholar, OpenGrey, and ProQuest) up to September 2020. According to the Population, Intervention, Comparison, Outcomes, Studies criteria, randomized clinical trials (RCTs) and observational studies that evaluated the effects of orthodontic force on dental pulp were included. Case series/reports, laboratory-based or animal studies, reviews, and studies that did not investigate the association between orthodontic force and pulpal changes were excluded. Newcastle-Ottawa Scale and Cochrane risk-of-bias tool were used to assess the risk of bias. The overall certainty level was evaluated with the Grading of Recommendations Assessment, Development and Evaluation tool. RESULTS: 26 observational studies and five RCTs were included. A detailed qualitative analysis of articles showed a wide range of samples and applied methodologies concerning impact of orthodontic force on the dental pulp. The application of orthodontic force seems to promote several pulpal histomorphological changes, including tissue architecture, cell pattern, angiogenesis, hard tissue deposition, inflammation, and alteration of the expression levels of 14 tissue factors. CONCLUSIONS: Although the included articles suggest that orthodontic forces may promote histomorphological changes in the dental pulp, due to the very low-level of evidence obtained, there could be no well-supported conclusion that these effects are actually due to orthodontic movement. Further studies with larger samples and improved methods are needed to support more robust conclusions.

Prevalence of degenerative disease in temporomandibular disorder patients with disc displacement: A systematic review and meta-analysis.

To assess the available literature on the prevalence of degenerative joint disease (DJD) in patients with anterior disc displacement (ADD) of the temporomandibular joint (TMJ), using a systematic review with meta-analysis. Search strategies were performed in the following databases: PubMed/MEDLINE, EMBASE, LILACS, Web of Science, Scopus, and LIVIVO. A search was also carried out in the gray literature. Two independent reviewers selected the included articles using a two-phase process based on the eligibility criteria. Three reviewers independently collected the required information from the included articles. The methodological quality of the selected studies was assessed individually. In accordance with the inclusion and exclusion criteria, 1349 studies were found and 18 articles were included. The total sample size was 3158 TMJs. The sex distribution was predominant for females (1161 females and 345 males). The average age was 46 (range 10-82) years. Among the 1762 TMJs quantitatively assessed, the prevalence of DJD involving disc displacement with reduction (DDWR) was 35%, while for disc displacement without reduction (DDWoR) the prevalence was 66%. The prevalences of different features of DJD were as follows: sclerosis 24.3%, erosion 23.5%, osteophyte 17.9%, and subcortical cyst 7.6%. The prevalence of DJD in temporomandibular disorder patients with disc displacement is around 50% and is higher in DDWoR (66%) than in DDWR (35%). Sclerosis and erosion would be the most expected radiological signs in a developing DJD. Clinicians should adequately address the frequent DJD features associated with disc displacement in terms of diagnostics and therapeutic management.

The influence of apical extent of root canal obturation on endodontic therapy outcome: a systematic review.

OBJECTIVES: This systematic review (SR) aimed to investigate the influence of obturation extent on the final outcome of root canal treatment (RCT), by answering the question "among patients requiring RCT on fully formed permanent teeth, is there an association between obturation extent and the final treatment outcome?" MATERIALS AND METHODS: Five electronic databases and three gray literature searches were performed. Observational studies investigating the association between obturation extent and RCT outcome in fully formed permanent teeth with a minimum follow-up of 12 months were included. We evaluated the risk of bias (RoB) in with MAStARI for cohort studies. The overall quality of the evidence was assessed with the GRADE-tool. RESULTS: Twenty-two studies were included, 2 had high RoB, 7 moderate RoB, and 13 low RoB. Underextended obturation demonstrated increased odds of an unfavorable outcome in seven studies, in which the odds varied between 6.94 (95%CI 2.20-21.87) and 1.73 (95%CI 1.02-2.95). Overextended obturation also demonstrated this association in four studies, with odds varying from 1.90 (95%CI 1.23-2.94) to 23.00 (95%CI 5.58-94.75). Due to heterogeneity and the very low level of evidence found in the GRADE analysis, the results from this SR should be interpreted with caution. CONCLUSIONS: Obturation extent seems to influence RCT outcome; overextended and underextended obturations showed higher chance of association with less favorable outcomes than adequate obturation; however, this association was not categorically supported. CLINICAL RELEVANCE: This SR provides information about obturation extent influence on RCT outcome and guides clinicians to make evidence-based decisions during endodontic practice.