Chemoselective and metal-free reduction of α,β-unsaturated ketones by in situ produced benzeneselenol from O-(tert-butyl) Se-phenyl selenocarbonate

The carbon–carbon double bond of arylidene acetones and chalcones can be selectively reduced with benzeneselenol generated in situ by reacting O-(tert-butyl) Se-phenyl selenocarbonate with hydrochloric acid in ethanol. This mild, metal-free and experimentally simple reduction procedure displays considerable functional-group compatibility, products are obtained in good to excellent yields, and the use of toxic Se/CO mixture and NaSeH, or the smelly and air-sensitive benzeneselenol, is avoided.

The carbon–carbon double bond of arylidene acetones and chalcones can be selectively reduced with benzeneselenol generated in situ by reacting O-(tert-butyl) Se-phenyl selenocarbonate with hydrochloric acid in ethanol.     

Clear aligner orthodontic therapy of rotated mandibular round-shaped teeth: A finite element study

Objective:To evaluate, using the finite element method, the orthodontic rotational movement of a lower second premolar obtained with clear aligners, analyzing different staging and attachment configurations.Materials and Methods:A CAD model including a complete lower dental arch (with element 4.5 mesially rotated 30°) and the corresponding periodontal ligaments, attachments, and aligner was designed and imported to finite element software. Starting from the CAD model, six projects were created to simulate the following therapeutic combinations for correcting element 4.5 position: (1) without attachments, (2) single attachment placed on the buccal surface of element 4.5, (3) three attachments placed on the buccal surfaces of teeth 4.4 to 4.6. For each project, both 1.2° and 3° of aligner activation were considered.Results:All the analyzed configurations revealed a clockwise rotation movement of element 4.5 on the horizontal plane. Models with attachments showed a greater tooth displacement pattern than models without attachments. Simulations with attachments and 3° of aligner activation exhibited the best performance concerning tooth movement but registered high stresses in the periodontal ligaments, far from the ideal stress levels able to produce tooth rotational movement.Conclusions:The model with a single attachment and 1.2° of aligner activation was the most efficient, followed by the three attachment model with the same degree of activation. Aligner activation should not exceed 1.2° to achieve better control of movement and reasonable stress in periodontal structures.     

Dentinal tubule penetration and root canal cleanliness following ultrasonic activation of intracanal‐heated sodium hypochlorite

This study investigated the effect of ultrasonic activation of intracanal‐heated sodium hypochlorite (NaOCl) on its dentinal tubular penetration and root canal cleanliness in vitro. In experiment 1, mandibular premolars were randomly allocated to three groups (n = 8): group A, ultrasonic activation; group B, ultrasonic activation of intracanal‐heated NaOCl and group C, syringe‐and‐needle irrigation. Penetration of the fluorescent‐labelled NaOCl was investigated using light microscopy. In experiment 2, mandibular premolars were randomly allocated to group B or C (n = 10), for histological analysis of the remaining pulp tissue and debris. Data were statistically analysed using Kruskal–Wallis and Mann–Whitney tests (P = 0.05). The highest penetration of NaOCl was observed in group B, followed by group A (P < 0.05). Group B showed significantly less amount of debris than group C (P < 0.05). Dentinal tubule penetration of NaOCl and root canal cleanliness were significantly improved by ultrasonic activation of intracanal‐heated NaOCl.     

Short ultrasonic debridement with adjunctive low-concentrated hypochlorite/amino acid gel during periodontal maintenance: randomized clinical trial of 12 months

Objectives

The objective of this study was to evaluate the benefit of repeated subgingival cleaning with a low-concentrated hypochlorite/amino acid gel in subjects in maintenance care with residual pockets ≥ 5 mm.

Material and methods

Examiner masked, randomized two-arm parallel design. Thirty-two adult periodontal patients in maintenance phase, > 3 months after periodontal therapy, with at least one residual periodontal pocket ≥ 5 mm, were randomly assigned to treatment by subgingival ultrasonic debridement with the gel or ultrasonic debridement only. At months 0, 4, and 8, all sites presenting with a probing depth (PD) ≥ 5 mm were treated. Six sites were monitored on each tooth. The primary end point was the presence or absence of PD ≥ 5 mm after 12 months. Secondary clinical outcomes were oral tissue safety; patient acceptance; changes in PD; bleeding on probing; recession after 4, 8, and 12 months; and the presence or absence of six target microorganisms in treated pockets at baseline, after 7 days and 4 months.

Results

A total of 365 sites in 32 patients with PD ≥ 5 mm were treated at baseline. At the final evaluation at month 12, 47% of these sites in the test and 49% in the control group were still in this PD category. The difference between baseline and month 12 was significant in both groups (p < 0.01), whereas the difference between groups was not. Repeated short ultrasonic instrumentation with adjunctive administration of the test product resulted in a clinical attachment level (CAL) gain of 1.02 mm (p < 0.01) and led to − 0.97 mm of pocket reduction (p < 0.01) without inducing further recession. However, repeated short ultrasonic debridement without the gel led to a similar clinical outcome (p < 0.01). No adverse events were recorded.

Conclusions

Short ultrasonic instrumentation of residual pockets with PD ≥ 5 mm during maintenance visits resulted in a clinically relevant CAL gain and PD reduction in the order of 1 mm in 1 year, without inducing further recession.

Clinical relevance

This study corroborates the benefit of regular maintenance care after periodontal therapy, including short debridement of the residual pockets.

     

Assessment of condylar volume and ramus height in JIA patients with unilateral and bilateral TMJ involvement: retrospective case-control study

The objectives of the study are to analyze volumetric differences of condylar volumes in patients with unilateral and bilateral JIA and to compare results     

The sandwich osteotomy technique to treat vertical alveolar bone defects prior to implant placement: a systematic review

Clinical Oral Investigations - The aim of this systematic review was to investigate the predictability of the sandwich osteotomy technique to provide sufficient alveolar bone height for dental...     

Dimensional changes following alveolar ridge preservation in the posterior area using bovine-derived xenografts and collagen membrane compared to spontaneous healing: a 6-month randomized controlled clinical trial

Clinical Oral Investigations - To assess dimensional changes following alveolar ridge preservation using bovine-derived xenograft with 10% collagen and collagen membrane compared to ridge...