João Carlos Ramos

The dog as a model for peri-implantitis: A review.

ABSTRACT Objective: To analyze the current available experimental canine models for peri-implantitis. Material and Methods: Electronic databases of the PubMed, EBSCOhost, and Cochrane Library were searched for dog studies on peri-implantitis induction methodology, until October 31, 2012. The eligibility of the studies for this review was based on the screening of two independent reviewers. Results: After screening, 50 publications were eligible for review. The most used animal model was the Beagle (n = 23). The bilateral mandible four premolar were the most extracted group of teeth (n = 20) and the majority of the studies had the placement of six implants in the jaw with only five (n = 5) of them reporting on interimplant distance. All publications reported peri-implantitis induction using ligature during a variable period of time and with a subsequent heterogeneous loss of peri-implant bone. The ligature placement and maintenance around the implant varied greatly between the publications. The constant use of ligatures, sometimes traumatically forced to the peri-implant sulcus, may influence the degree of bone loss during canine experimental peri-implantitis overlapping the contribution of implant surface to the onset and development of this pathology. Conclusions: A great heterogeneity exists among the studies reporting on the induction of peri-implantitis in canine. Experimental peri-implantitis model has suffered a change through the last years, from an exclusive ligature-induced to a ligature-induced and nonligature induced progression, thus approaching the natural occurrence of this pathology. The ideal canine peri-implantitis induction model would be a naturally occurring peri-implanititis induction without the action of any ligature.

Histologic Evaluation of Regenerative Endodontic Procedures with the Use of Chitosan Scaffolds in Immature Dog Teeth with Apical Periodontitis

Introduction The aim of this study was to evaluate histologically the newly formed tissues after regenerative endodontic procedures (REPs) in dogs using either a blood clot (BC) or 2 different formulations of a chitosan hydrogel as scaffolds. Methods Apical periodontitis was induced by inoculating immature teeth with oral plaque in 4 beagle dogs. Teeth (n = 96) were divided into 2 control (n = 20) and 4 test groups (n = 76) according to the treatment: apexification and REPs with BC, sodium hyaluronate:chitosan (HA:CS) scaffolds, or pectin:chitosan (P:CS) scaffolds. All root canals were disinfected with 2.5% sodium hypochlorite and a triple antibiotic paste intracanal medicament before evoked bleeding, clot formation, or scaffold placement. Thirteen weeks after treatment, the animals were sacrificed and the jaw blocks harvested for histologic processing, histomorphometric analysis, and statistical analysis. Results The lumens of the root canals were completely filled with mineral trioxide aggregate with evidence of a mineralized apical bridge between the root canal walls in 83% of the samples in the apexification group. Vital vascularized tissue was found in the REP groups; apical closure happened in 66.7% of these treatments, and root growth was detected more often as an increase in thickness (85.6%) than in length (45.6%). The greatest amount of mineralized tissue inside the canal was observed in the BC group, with statistical significance compared with the HA:CS and P:CS groups (P < .05). Further histologic evaluation revealed the presence of apical papilla. Conclusions The addition of chitosan scaffolds to blood in regenerative procedures in dogs did not improve the formation of new mineralized tissues along the root canal walls or the histologic evidence of the regeneration of a pulp‐dentin complex.

Clinical Change in Cognitive Distortions and Core Schemas After a Cognitive-Behavioral Group Intervention: Preliminary Findings from a Randomized Trial with Male Prison Inmates

AbstractThe goal of this pilot study was to assess the efficacy of a cognitive–behavioral program in reducing cognitive distortions and schemas in prison inmates. The Angry Cognitions Scale and the Young Schema Questionnaire was answered by a treatment and control group, and the treatment effects were tested using ANCOVA with baseline as covariate and condition as fixed factor. In order to assess clinical change, the Reliable Change Index was computed. At baseline, no differences were found between groups, except for one subscale of the Angry Cognitions Scale (Maladaptive Processes), where controls scored higher than treatment subjects. ANCOVA showed significant differences between groups at post-treatment, with treatment subjects presenting lower scores on the studied variables. Concerning clinical change, differences between groups were observed in the distributions by change categories in the majority of the variables. These outcomes offer preliminary evidence of the program’s ability to change cognitive variables underlying antisocial behavior.

Cuspal Displacement Induced by Bulk Fill Resin Composite Polymerization: Biomechanical Evaluation Using Fiber Bragg Grating Sensors

Polymerization shrinkage is a major concern to the clinical success of direct composite resin restorations. The aim of this study was to compare the effect of polymerization shrinkage strain of two resin composites on cuspal movement based on the use of fiber Bragg grating (FBG) sensors. Twenty standardized Class II cavities prepared in upper third molars were allocated into two groups (n = 10). Restorations involved the bulk fill placement of conventional microhybrid resin composite (Esthet•X® HD, Dentsply DeTrey) (Group 1) or flowable “low-shrinkage” resin composite (SDR™, Dentsply DeTrey) (Group 2). Two FBG sensors were used per restoration for real-time measurement of cuspal linear deformation and temperature variation. Group comparisons were determined using ANCOVA (α = 0.05) considering temperature as the covariate. A statistically significant correlation between cuspal deflection, time, and material was observed (p < 0.01). Cuspal deflection reached 8.8 μm (0.23%) and 7.8 μm (0.20%) in Groups 1 and 2, respectively. When used with bulk fill technique, flowable resin composite SDR™ induced significantly less cuspal deflection than the conventional resin composite Esthet•X® HD (p = 0.015) and presented a smoother curve slope during the polymerization. FBG sensors appear to be a valid tool for accurate real-time monitoring of cuspal deformation.

Adhesion in Restorative Dentistry

Bonding agents play a crucial role in the effective sealing and retention of resin-based composite restorations, which have been increasingly placed and replaced by dentists in many countries around the world. In fact, direct adhesive restoration with composite resins has become the procedure of choice for the treatment of anterior and posterior teeth. However, long-term durability of those restorations may be compromised due to progressive loss of the integrity of adhesive interfaces. This means that no adhesive strategy is free from technique sensitivity. The specificity and proportion of different constitutive molecules, the interaction between them and substrates can differ greatly from one class of adhesive system to another, which can affect bond quality. Protocol simplification has been an inevitable trend that has boosted the use of self-etching and universal systems in adhesive dentistry. However, there is a lack of randomized clinical trials to prove the effectiveness of these systems. This chapter gives an overview of the most important issues in dental adhesion and adhesive systems, as well, discussing their composition and clinical use.

Type 1 diabetes in children is not a predisposing factor for oral yeast colonization.

Abstract Type 1 diabetes mellitus (T1D) is considered a risk factor associated with oral yeast infections. The aim of this study was to evaluate the yeast oral carriage (in saliva and mucosal surface) of children with T1D and potential relation with host factors, particularly the subset of CD4+ T cells. Yeasts were quantified and identified in stimulated saliva and in cheek mucosal swabs of 133 diabetic T1D and 72 healthy control subjects. Salivary lymphocytes were quantified using flow cytometry. The presence of yeasts in the oral cavity (60% of total patients) was not affected by diabetes, metabolic control, duration of the disease, salivary flow rate or saliva buffer capacity, by age, sex, place of residence, number of daily meals, consumption of sweets or frequency of tooth brushing. Candida albicans was the most prevalent yeast species, but a higher number of yeast species was isolated in nondiabetics. T1D children with HbA1c ≤ 7.5 (metabolically controlled) presented higher number of CD4+ T salivary subsets when compared with the other groups of children (non‐diabetic and nonmetabolically controlled) and also presented the highest number of individuals without oral yeast colonization. In conclusion, T1D does not predisposes for increased oral yeast colonization and a higher number of salivary CD4+T cells seems to result in the absence of oral colonization by yeasts.