A 32-month evaluation of lithium disilicate cantilever resin-bonded fixed dental prostheses to replace a missing maxillary incisor.

STATEMENT OF PROBLEM: The absence of a tooth in the esthetic zone can cause emotional and social distress. The use of minimally invasive and visually pleasing lithium disilicate resin-bonded fixed dental prostheses (RBFDPs) may be a suitable option for replacing a missing maxillary incisor. However, the available literature on lithium disilicate cantilever RBFDPs is limited. PURPOSE: This retrospective multicenter study assessed the survival and success rates of lithium disilicate anterior cantilever RBFDPs with an average follow-up period of 3 years up to 9 years. MATERIAL AND METHODS: RBFDPs delivered by 3 operators were clinically assessed for survival using a modified United States Public Health Service criteria list. The incidence density was determined for each criterion and operator. The standard error and 95% confidence interval were calculated for each incidence density difference (α=.05 for all analyses). RESULTS: A total of 108 RBFDPs were evaluated after a mean period of 32.45 months, ranging from 14 days to 111 months. None of the restorations exhibited failure, carious lesions, or fractures during the follow-up period. The primary reasons for reduced success rates were inflammation of the surrounding soft tissues and discoloration, with incidence densities of 0.074 and 0.057 per year, respectively. Significant differences were observed among RBFDPs from different operators for criteria that included adaptation, color match, marginal adaptation, polishability, surface staining, gingival health, and antagonist wear. CONCLUSIONS: Cantilever lithium disilicate RBFDPs appear to be suitable for short-term restoration. RBFDPs exhibited visible changes after short-term follow-up. However, these changes did not result in failure.

Fracture strength of lithium disilicate cantilever resin bonded fixed dental prosthesis.

OBJECTIVES: Metal and Zirconia cantilever resin bonded fixed dental prosthesis (RBFDPs) are extensively used when missing anterior teeth. Lithium disilicate is not used a lot as it is not indicated by the manufacturers. The aim of this in vitro study was to investigate the fracture strength of lithium disilicate cantilever RBFDPs with different configurations and compare them to metal and zirconium RBFDPs. METHODS: Sound extracted human canines (N = 60) were divided into six groups, to be restored with a cantilever RBFDP. Specimen were randomly divided over 6 groups (n = 10): Full crown of lithium disilicate (FCL); Veneer wing of lithium disilicate (VL); Connector of lithium disilicate (CL); Palatal wing of lithium disilicate (PL); Palatal wing of zirconia (PZ) and Palatal wing of metal ceramic (PM). All bridges were bonded with an adhesive system. After thermalcyclic ageing (20 × 103x, 5-55 °C) all samples were loaded until fracture occurred. Failure types were classified and representative SEM done. RESULTS: The mean fracture strength results per group were: 588N (FCL) 588N (PM), 550N (CL), 534N (PL), 465N (VL), 38N (PZ). A significant (p = 0.001) difference was found between the groups, all groups had a higher fracture strength than the zirconia RBFDPs. Failure type analysis showed some trends among the groups. Irrepairable fractures of the root were only seen in samples restored with lithium disilicate. Metal and zirconia RBFDPs predominantly failed on the adhesive interface, where 60% of the zirconia samples had pretest debondings. SIGNIFICANCE: No differences in fracture strength were found between cantilever RBFDPs made from metal or lithium disilicate. Metal (0% pre-test failures) and zirconium (60% pretest failures) RBFDPs failed predominantly on the adhesive interface whereas the lithium disilicate (0% pre-test failures) samples showed fractures in the contact area. The least invasive connector (CL) and Metal (PM) RBFDP obtained a high fracture strength and optimal fracture pattern.

Deep margin elevation versus crown lengthening: biologic width revisited.

This article revisits the concept of biologic width, in particular its clinical consequences for treatment options and decisions in light of modern dentistry approaches such as biomimetics and minimally invasive procedures. In the past, due to the need to respect biologic width, clinicians were used to removing periodontal tissue around deep cavities, bone, and gum so that the limits of restorations were placed far away from the epithelium and connective attachments, in order to prevent tissue loss, root exposure, opening of the proximal area (leading to black holes), and poor esthetics. Furthermore, no material was placed subgingivally in case it led to periodontal inflammation and attachment loss. Today, with the more conservative approach to restorative dentistry, former subtractive procedures are being replaced with additive ones. In view of this, one could propose deep margin elevation (DME) instead of crown lengthening as a change of paradigm for deep cavities. The intention of this study was to overview the literature in search of scientific evidence regarding the consequences of DME with different materials, particularly on the surrounding periodontium, from a clinical and histologic point of view. A novel approach is to extrapolate results obtained during root coverage procedures on restored roots to hypothesize the nature of the healing of proximal attachment tissue on a proper bonded material during a DME. Three clinical cases presented here illustrate these procedures. The hypothesis of this study was that even though crown lengthening is a valuable procedure, its indications should decrease in time, given that DME, despite being a very demanding procedure, seems to be well tolerated by the surrounding periodontium, clinically and histologically.

The scalpel finishing technique: a tooth-friendly way to finish dental composites in anterior teeth.

Optimal results can be obtained on direct restorations by the application of layering procedures that combine the accurate morphological insertion of restorative materials with the knowledge of the optical and mechanical properties of both composite resin and natural hard dental tissue. Even if the finishing procedures on restorations, such as margination (the trimming of margins), are minimized by anatomical layering techniques, finishing can still be highly complicated due to a number of pre-finishing sequences using specific instruments proposed in the literature, which include finishing burs and abrasive discs. Finishing procedures performed with a scalpel on polymerized direct composite restorations can improve the quality of the final sculptured surface by developing natural contours and characteristics and by removing the excess restorative material at the tooth-structure margin. Enhanced movement control and fine fingertip perception of the surface texture while moving the scalpel blade allow the operator to detect and cut the excess composite material during the margination procedure and to refine the final anatomy. Avoiding the use of finishing burs during finishing procedures on direct composite restorations may save adjacent enamel surfaces from abrasive damage. The composite surface and margins may also benefit from using the scalpel finishing technique, considering the potential risk of excess removal and surface crazing that the improper use of finishing burs could cause to composite material. The purpose of this article is to propose and describe the scalpel finishing technique step by step, as well as to briefly discuss the advantages of its application within the limits of a clinical case report.

Ceramic adhesive restorations and biomimetic dentistry: tissue preservation and adhesion.

Thanks to sophisticated adhesive techniques in contemporary dentistry, and the development of composite and ceramic materials, it is possible to reproduce a biomimetic match between substitution materials and natural teeth substrates. Biomimetics or bio-emulation allows for the association of two fundamental parameters at the heart of current therapeutic treatments: tissue preservation and adhesion. This contemporary concept makes the retention of the integrity of the maximum amount of dental tissue possible, while offering exceptional clinical longevity, and maximum esthetic results. It permits the conservation of the biological, esthetic, biomechanical and functional properties of enamel and dentin. Today, it is clearly possible to develop preparations allowing for the conservation of the enamel and dentin in order to bond partial restorations in the anterior and posterior sectors therefore limiting, as Professor Urs Belser from Geneva indicates, "the replacement of previous deficient crowns and devitalized teeth whose conservation are justified but whose residual structural state are insufficient for reliable bonding."1 This article not only addresses ceramic adhesive restoration in the anterior area, the ambassadors of biomimetic dentistry, but also highlights the possibility of occasionally integrating one or two restorations at the heart of the smile as a complement to extensive rehabilitations that require more invasive treatment.

Infiltration, a new therapy for masking enamel white spots: a 19-month follow-up case series.

Enamel white spot lesions are frequent and can impact patients' quality of life. The most conservative treatment in such cases is microabrasion, a technique that presents some drawbacks. The proposed strategy is not based on the elimination of dysplastic enamel, but on masking the lesion by infiltrating the porous subsurface enamel with a hydrophobic resin that has a refraction index closer to that of sound enamel, after permeating the non-porous surface enamel through hydrochloric acid erosion. Erosion-infiltration approaches have been proposed to treat initial caries, but this report suggests extending it to two novel indications: fluorosis and traumatic hypo-mineralization lesions. Four cases were treated by erosion infiltration following the original protocol. They were followed up clinically at several intervals during a period of 19 months of clinical service. The clinical results, although not perfect, satisfied the patients entirely. Erosion infiltration could be a promising alternative for minimally invasive treatment in similar situations.

White defects on enamel: diagnosis and anatomopathology: two essential factors for proper treatment (part 1).

Early-stage caries (white spots), fluoroses, traumatic hypomineralizations and molar incisive hypomineralization (MIH) all present, to differing degrees, clinical symptoms involving white marks on the enamel. This article shows that proper diagnosis leads to better understanding of the three-dimensional aspects of the lesion, thereby ensuring the appropriate choice of a specific treatment.

Effectiveness of a new one-step self-etch adhesive in the restoration of non-carious cervical lesions: 2-year results of a randomized controlled practice-based study.

OBJECTIVES: The purpose of this practice-based randomized controlled trial was to evaluate the effectiveness of a new one-step self-etch adhesive to restore non-carious cervical lesions following CONSORT guidelines and to test the hypothesis that this adhesive is equally effective with or without beforehand selective etching of enamel. METHODS: Twenty-eight patients each received two restorations randomly assigned to the control or the experimental group. In the control group, the adhesive (Bond Force, Tokuyama) was applied without beforehand enamel phosphoric-acid-etching, whereas the latter was applied first in the experimental group. The restorative composites used for all restorations were Estelite Flow Quick followed by Estelite Sigma (Tokuyama). The clinical effectiveness was assessed at baseline, 6 months, 1 year and 2 years in terms of retention, marginal staining, restoration staining, and post-operative sensitivity. RESULTS: One restoration loss occurred in the control group before the 6-month recall. At the two-year recall, only 2 secondary endpoints showed significant differences between groups: marginal staining at the enamel occurred more often in the control group (29% vs. 5%) (hierarchical linear regression: p=0.011) and 'minor marginal defects' were significantly more frequent in the control group (29% vs. 0%) (hierarchical linear regression: p=0.009). SIGNIFICANCE: Although in a practice setting, the effectiveness of this new adhesive was very good after 2 years of clinical service. More minor defects and restoration staining at the enamel margin were noticed when enamel had not been selectively acid-etched. Selective enamel acid-etching might enhance the adhesive properties of this new one-step self-etch adhesive.

Contemporary aesthetic care for nonvital teeth: conservative treatment options.

UNLABELLED: This article presents a series of considerations for the adhesive restoration of the nonvital tooth. Although ensuring the marginal integrity of all elements is critical to the final restoration, the most important parameter in the restoration of an endodontically treated tooth is the evaluation of the loss of substance in volume, architecture, and location. It is also important for the dentist to consider other clinical parameters (eg, the age of the patient, the length of time since trauma, even the occlusal scheme) prior to initiating care for these teeth. LEARNING OBJECTIVES: This article advocates the clinician's conservation of natural tooth structure when providing care to preserve the root anchorage due to repeated and invasive work that can result in microfractures or loss of tooth. Upon reading this article, the reader should: * Understand the need to preserve tooth structure by performing partial-coverage restorations. * Become more familiar with the indications for resin-bonded restoration for a devital tooth.