Can discolored dental composites be bleached in depth?

Objectives: Previous in vitro studies determined the whitening effects of bleaching products on stained resin composite surfaces. This in vitro study aimed to verify the effectiveness of a whitening system on composite resin previously subjected to pigmentation, specifically examining the depth of whitening effectiveness within the material structure. Materials and Methods: A commercially available nano-filled composite resin was used. Specimens were stained using a coffee-based solution and a 10% carbamide peroxide-based gel was employed as the whitening agent. The pigment's penetration and the effect of the bleaching gel were evaluated by measuring color (CieLab values) from the outer edge to the inner part of the specimens. Color measurements were taken at 14 points, starting from 0.1 mm from the external perimeter up to 3.0 mm. Results: Analysis of variance tests showed a statistically significant difference between the Control Group (CG), Pigmentation Group, and Whitening Group. The whitening agent was effective up to 1.5 mm in depth, with Whiteness index (W) values not statistically different from those of CG up to 0.5 mm in depth. Conclusions: Whitening agents on nano-filled resin composite previously pigmented appear effective in restoring the W to values similar to the original, particularly in the superficial layers of the sample.

Agenesis of the maxillary permanent lateral incisors with the deciduous retained: Conservative and biomimetic approach using the BAIR technique.

OBJECTIVE: Agenesis of the maxillary permanent lateral incisors is a condition that requires treatment aimed at improving the esthetics, even at an early age. However, traditional therapeutic protocols are long, invasive and have limitations and contraindications imposed by the age of the patient. CLINICAL CONSIDERATIONS: Recent developments in restorative dentistry have provided a new approach to this clinical situation, in particular when the deciduous laterals are retained. We report two cases regarding the management of missing lateral incisors using Biologically Active Intrasulcular Restoration (BAIR) technique. The BAIR technique allows us to transform the shape of the deciduous lateral incisor into the permanent, acting both on the dental morphology and proportions, and on the appearance of the soft tissues and the gingival parables. CONCLUSIONS: The BAIR technique is a valid approach to cases of agenesis of the maxillary permanent lateral incisors, when the deciduous are retained. It does not require any preparation of the dental tissues, is reversible and minimally invasive. It is applicable to patients of all ages, and results are obtained in a single appointment. CLINICAL SIGNIFICANCE: The BAIR technique allows a biomimetic conservative approach for the rehabilitation of congenitally missing permanent lateral incisors, when the deciduous are retained. It is a non-invasive protocol and effective in successfully restoring esthetics.

Maxillary Anterior Teeth Dimensions and Relative Width Proportions: A Narrative Literature Review.

Predictable results in the aesthetic treatment of anterior teeth can be obtained by resorting to the concept of dental aesthetics and, in particular, defining the ideal tooth dimensions and proportions to obtain a harmonious smile. Considering the great variety of articles dealing with the topic, and the lack of updated reviews, this narrative literature review aims to evaluate current knowledge on anterior teeth dimensions and to verify the existence and the potential applications of the anterior teeth proportioning theories (Golden Proportion, Golden Percentage, RED Proportion, and Golden Rectangle). PubMed, Embase, Cochrane Library, and Google Scholar databases were comprehensively searched using different keywords and term combinations. The research includes articles published up to June 2023, no time limits were set, and only articles in English were included. Inclusion criteria comprehended reviews, clinical studies, and in-vitro studies. A total of 66 articles were selected. Two main topics were identified: "Anterior teeth dimensions", "Golden Proportions, Golden Percentage, RED Proportions, and Golden Rectangle". As far as tooth dimensions are concerned, different width ranges are recognized for men and women and for different ethnic groups. Perfectly symmetric contralateral elements are found in low percentages of subjects. The correlation between dental dimensions and facial parameters is not always present, and it strongly depends on the sample's ethnicity and gender. Ideal tooth proportions were only partially identified.

Stain Susceptibility of Composite Resins: Pigment Penetration Analysis.

Composite resins are considered the material of choice for esthetic direct restorations, considering both their satisfying esthetic and mechanical properties. The success of composite resin restorations depends highly on their color stability. Discoloration causes color mismatch, consequent patient dissatisfaction, and eventually additional costs for correction/replacement of the restoration. The purpose of this study was to evaluate the degree of pigment penetration within the composite resins, in order to understand how discoloration can be treated properly. Two different commercially available composite resins were compared in the study: a nano-filled composite resin and a non-homogeneous micro-hybrid composite resin. A coffee solution was used to induce staining of the materials. Subsequently, the penetration of the pigments was measured by analyzing the color from the outside to the inside of the specimen. 14 levels were analyzed starting from 0.1 mm to 3.0 mm in depth. The ANOVA test demonstrated a statistically significant difference (p < 0.0001) between test and control groups up to a depth of 1.0 mm for the nano-filled composite and up to a depth of 2.0 mm for the non-homogeneous micro-hybrid composite. The two composite resin materials, subjected to pigmenting treatment, underwent a color variation with different patterns.

Intrasulcular Restorations of Anterior Teeth According to the BAIR Technique: Evaluation of Periodontal Parameters.

Some clinical situations, such as the closure of pronounced diastemas, and the transformation of malformed, small, or peg-shaped teeth, require a rebalancing of dental proportions accompanied by a modification of the gingival contour. A traditional treatment plan can include surgical, prosthetic, and/or orthodontic treatments. In some cases, it can be considered too invasive, and not all patients are willing to undertake long therapies. To overcome these limitations, a possible solution could be the application of the Biologically Active Intrasulcular Restoration (BAIR) technique, which allows us to modify the natural emergence tooth profile using simple intrasulcular direct restorations. The aims of this paper are to investigate possible effects on gingival health, and to assess the patient satisfaction about the aesthetic intervention performed. Periodontal data were collected, and patient satisfaction was registered using the VAS questionnaire. All sites healed without complications, no adverse events were registered or reported by the patients, and no signs of periodontal morbidity were visible. The results show that the patients evaluated the final aesthetics in a positive way, and they perceived a good condition of periodontal health as well. The intervention is felt as almost painless, and patients do not report significant post-operative distress. In conclusion, the BAIR technique can provide a valid therapeutic alternative for patients for whom traditional treatments are not indicated. It is a minimally invasive intervention where both the operating times and the biologic and economic costs are reduced.

Integrating Psychophysiology within Clinical Practice: A Pilot Cross-sectional Study on Prodromal Symptoms of Schizophrenia, Emotion Regulation, and Personality Functioning.

OBJECTIVE: To investigate the association between prodromal symptoms of schizophrenia, autonomic activity, and personality functioning. METHOD: 10 adolescents underwent semi-structured interviews assessing prodromal symptoms of schizophrenia and personality functioning. Cardiac activity was recorded at baseline, during the clinical interviews, and at recovery to assess concurrent changes in autonomic functioning. RESULTS: During the assessment of prodromal symptoms of schizophrenia, participants increased sympathetic activation compared to the recovery condition, and reduced vagal activation compared to the assessment of interpersonal functioning. CONCLUSIONS: The findings highlight the importance of integrating the autonomic assessment in clinical psychiatric and psychological practice.

Accuracy of Digital Impressions in Fixed Prosthodontics: A Systematic Review of Clinical Studies.

PURPOSE: To determine the accuracy of direct digital impressions in vivo and compare it to that of conventional impressions in order to assess whether intraoral scanners could be a legitimate alternative for the manufacturing of fixed prosthodontics. MATERIALS AND METHODS: An electronic systematic search was conducted in the PubMed, Web of Science, Embase, and Cochrane Library databases using query terms such as digital impression; intraoral digital impression; intraoral scanner; intraoral digital scanner; conventional impression; analogue impression; and accuracy. The outcomes were the trueness and precision of digital impressions in comparison to those of high-precision conventional impressions in vivo. RESULTS: Six studies matched the inclusion criteria. Four studies investigated the precision of digital impressions, while two studies focused on their trueness. Even if all the authors agreed that conventional impressions were more accurate than digital impressions in vivo, they gave different opinions on using intraoral scanners in a clinical context without causing misfit of the final restoration. CONCLUSION: According to the results of the present review, conventional impressions performed using high-precision impression materials showed greater accuracy than digital impressions. However, additional studies assessing the accuracy of digital impressions in a wider variety of clinical situations are highly recommended.

Adhesion to Zirconia: A Systematic Review of Current Conditioning Methods and Bonding Materials.

Background. Reliable bonding between resin composite cements and high strength ceramics is difficult to achieve because of their chemical inertness and lack of silica content that makes etching impossible. The purpose of this review is to classify and analyze the existing methods and materials suggested to improve the adhesion of zirconia to dental substrate by using composite resins, in order to explore current trends in surface conditioning methods with predictable results. Methods. The current literature, examining the bond strength of zirconia ceramics, and including in vitro studies, clinical studies, and a systematic review, was analyzed. The research in the literature was carried out using PubMed and Cochrane Library databases, only papers in English, published online from 2013 to 2018. The following keywords and their combinations were used: Zirconia, 3Y-TZP, Adhesion, Adhesive cementation, Bonding, Resin, Composite resin, Composite material, Dentin, Enamel. Results. Research, in PubMed and Cochrane Library databases, provided 390 titles with abstracts. From these, a total of 93 publications were chosen for analysis. After a full text evaluation, seven articles were discarded. Therefore, the final sample was 86, including in vitro, clinical studies, and one systematic review. Various adhesive techniques with different testing methods were examined. Conclusions. Airborne-particle abrasion and tribo-chemical silica coating are the pre-treatment methods with more evidence in the literature. Increased adhesion could be expected after physico-chemical conditioning of zirconia. Surface contamination has a negative effect on adhesion. There is no evidence to support a universal adhesion protocol.