Quintessence International, 09/2013

Self-etch bonding systems are promoted as a time-saving and user-friendly alternative to etch-and-rinse bonding systems. Self-etch adhesives are characterized by a relatively mild etching effect, resulting in a relatively low incidence of postoperative hypersensitivity. On the other hand, their mild etching effect causes a reduction in bond strength to enamel compared to that achieved with phosphoric acid etching. All-in-one adhesives still suffer from less-than-optimal initial bond strengths and from inadequate durability of the bond. Future developments need to focus on the elimination of water deposits along the adhesive interface of all-in-one adhesives. While self-etch adhesives may yield acceptable results when applied in combination with light-cured composite resin, their acidic monomers inhibit the polymerization of auto-cured and dual-cured composite resins. Unfortunately, most "self-cure" or "dual-cure" activators do not overcome this problem. This incompatibility has to be taken into consideration when using self-etch adhesives for adhesive cementation and for core build-up restorations. When assessing self-etch bonding systems, it should be noted that they do not represent a homogenous category of materials but rather comprise a great variety of different types of products, each with specific strengths and weaknesses. Keywords: adhesive cementation, core build-up restorations, direct composite restorations, dentin sealing, fiber-reinforced composite root canal posts, fissure sealing, self-etch bonding systems

Objective: The present study attempted to find a simple direct adhesive restorative technique for the restoration of Class 2 cavities. Method and Materials: A self-etch adhesive system with a dual-cured core buildup composite resin (paste 1 + paste 2) was evaluated in its ability to restore proximo-occlusal cavities with margins located on enamel and dentin. The groups were: A, cavity filling (cf) with paste 1 (light-curing component) by using a layering technique; B, cf by mixing both pastes, bulk insertion, and dual curing; and C, cf by mixing both pastes, bulk insertion, and chemical curing. Two control groups (D, negative, bulk; and E, positive, layering technique) were included by restoring cavities with a classic three-step etch-and-rinse adhesive and a universal restorative composite resin. SEM margin analysis was performed before and after thermomechanical loading in a chewing simulator. Results: Percentages (mean ± SD) of "continuous margins" were improved by applying the material in bulk and letting it self cure (54 ± 6) or dual cure (59 ± 9), and no significant differences were observed between these two groups and the positive control (44 ± 19). Conclusion: The present study showed that the dual-cured composite resin tested has the potential to be used as bulk filling material for Class 2 restorations. Clinical relevance: When used as filling materials, dual-cure composite resins placed in bulk can provide marginal adaptation similar to light-cured composites applied with a complex stratification technique. Keywords: amalgam substitute, bulk filling, Class 2 restoration, dual cure, marginal adaptation, self cure

A localized periodontal defect associated with an unusual furcation on a mandibular central incisor and its treatment sequences are presented. A 54-year-old woman presented with a persistent localized periodontal defect, which was not responsive to nonsurgical periodontal therapy. An exploratory surgery revealed complete through and through furcation involvement on the right mandibular central incisor, resulting in a three-walled infrabony defect. Following thorough mechanical debridement and root planing, the infrabony aspect of the defect was grafted with freeze-dried bone allograft combined with the recombinant human platelet-derived growth factor-BB. The flaps were positioned to enable patient's home care and professional dental cleaning. Follow-up examination revealed uneventful healing and resolution of the infrabony periodontal defect. Clinicians should be aware of this unusual condition and consider it as a potential etiology when dealing with a persistent localized periodontal defect in the mandibular anterior sextant, which may not respond to the conventional nonsurgical periodontal therapy. Eliminating the active disease as well as enabling careful maintenance and oral hygiene may prevent further deterioration and result in a stable long-term outcome preserving the compromised tooth. Keywords: furcation, guided tissue regeneration, infrabony defect, recombinant human platelet-derived growth factor-BB, tooth anatomy

Objective: To evaluate and compare the effect of three different implant positions on strain developed around four implants supporting a mandibular overdenture with rigid telescopic attachments. Method and Materials: Three experimental acrylic resin overdentures were fabricated on three edentulous mandibular acrylic models. Four implants were placed in each model. According to the implant positions, the models were classified into three groups: in group I (quadrilateral design) the implants were placed at canine and first molar areas; in group II (curved design) the implants were placed at canine and second premolar areas; and in group III (linear design) the implants were placed at lateral incisor and first premolar areas. Overdentures were connected to the implants with rigid telescopic attachments. Eight linear strain gauges were bonded to the acrylic resin around each implant at two sites (mesial and distal). Strains were measured for anterior (lateral incisor and canine) and posterior (premolar and molar) implants at both mesial and distal sites during bilateral and unilateral load applications. Results: For bilateral and unilateral load applications, group II recorded the highest strain values while group I recorded the lowest. In group II and group III, strain values at distal sites were significantly higher than values at mesial sites. Strain values of posterior implants were significantly higher than values of anterior implants in all groups. The greatest strain values were recorded at the loading side during unilateral load application. Conclusion: Quadrilateral design showed minimal peri-implant strain compared to curved or linear designs. This design may be recommended when rigid telescopic crowns are used to connect mandibular overdentures to four implants. Keywords: implant overdenture, implant position, strain, telescopic copings

Objectives: The residual alveolar bone height at the implant recipient site plays a key role in determination of the risk of sinus membrane perforation during crestal sinus elevation. In this study, we aimed to determine the correlation between residual ridge height and perforation limit of sinus membrane and to examine the safety range for the sinus membrane continuity in crestal sinus elevation. Formalin-fixed cadavers were used for the experiment to observe outcomes. Method and Materials: Crestal sinus elevations were performed on 14 preserved human cadavers' heads. Residual ridge heights were measured using a bone caliper. The physiodispenser was preset to 30 Ncm and sinus floors were elevated by a concave sinus screw with diameter of 4 mm until sinus membrane perforation occurred. The perforations were identified either as Class I or Class II and the portion of the concave sinus screw in the sinus was measured each time using a ruler. Spearman's correlation coefficient was calculated to show the relation between the residual ridge heights and the membrane elevations at the time of perforation of the sinus membranes. Results: In general, the perforation limit of sinus membrane after elevation was higher with greater residual ridge height. A statistically significant correlation was found between residual ridge heights and perforations of the sinus membrane (r = 0.620, P < .001). Conclusion: Although it is not always possible to extrapolate results from cadavers to an in vitro clinical setting, it could be considered to have clinical significance. Our findings suggest that higher subsinusoidal elevation may be achieved when the residual ridge bone height increases. The conclusions of this study should be verified with studies of more rigorous design. Keywords: crestal approach, perforation, sinus lift

Oral lichenoid lesions (OLLs) are a diverse group of disorders that may be attributed to an autoimmune etiology, underlying systemic disease, or in association with an identifiable causative agent, such as a medication, food product, or dental material. OLLs commonly present with striae, erythema, and/or ulceration on affected oral mucosa and can be symptomatic. The aim of this report is to describe a case of OLLs that were believed to be attributed to use of household laundry detergent to clean an oral occlusal appliance. Keywords: laundry detergent, oral lichenoid lesion

Pain arising from surgical procedures that damage the inferior alveolar nerve typically responds poorly to classic therapies. The present case reports the successful medical treatment of this problem with a 10-day course of a corticosteroid and a concomitant 30-day course of an anticonvulsant. Keywords: dental extraction, neuropathic pain, trauma

Objective: Arginine-containing toothpastes are a promising new treatment for dentin hypersensitivity (DH), which afflicts a considerable number of patients. However, there have to date been only individual studies. We aim to present an overview of the clinical evidence in order to determine trends and establish firmer conclusions regarding the use of arginine-containing toothpastes for management of DH. Method and Materials: A protocol was developed based on the Cochrane Handbook for Systematic Reviews of Interventions (version 5.1.0), including: search strategy, selection criteria, data extraction, and risk of bias assessment. We searched electronic databases (up to October 2012) without language limitation, and reference lists of relevant papers for randomized controlled trials that assessed the efficacy of arginine-containing toothpastes for DH treatment. Data extraction and domain-based risk of bias assessment were independently performed by two reviewers. The meta-analysis was performed in STATA (version 12.0). The GRADE analysis was conducted in GRADE profiler (version 3.6). Results: Fourteen randomized controlled studies with different risk of bias were included in the meta-analysis, all evaluated by tactile and air blast assessment. The mean differences and standard deviations for each treatment group were pooled for analysis using a random-effect model. We found that arginine-containing toothpastes had better overall effects in comparison with placebo toothpastes (P < .05), potassium salt-containing toothpastes (P < .05), and strontium-containing toothpastes (P < .05). The GRADE analysis showed that quality of the evidence was moderate when arginine-containing toothpastes were compared to placebo and potassium salt-containing toothpastes, and quality of the evidence was low with comparison to strontium-containing toothpastes. Conclusion: Current available clinical evidence suggests that arginine-containing toothpastes are associated with the reduction of DH compared to both placebo and positive control toothpastes. However, there are limitations to the current studies, and more well-designed trials are needed to confirm the efficacy. Keywords: arginine, dentin sensitivity, GRADE analysis, meta-analysis, systematic review, toothpaste