Instrumental and Visual Evaluation of the Chameleon Effect of Single-shaded Composite Resins.

OBJECTIVE: To evaluate the shade-matching ability of single-shade resin-based composite restorations in different thicknesses using both instrumental and visual techniques. METHODS AND MATERIALS: Cavities with 4 mm diameter and 2 mm (n=96) or 3 mm (n=96) depth were prepared in acrylic incisor teeth of shades A2, A3, B3, and C2 and restored with three single-shade resin composites, Omnichroma (Tokuyama Dental America, Encinitas, CA, USA [OM]), Vittra APS Unique (FGM Dental Group, Joinville, SC, Brazil [VU]), Zenchroma (President Dental, Allershausen, Germany [ZC]), and a microhybrid resin composite (Filtek 3M Z250 3M ESPE, St Paul, MN, USA [FZ]) of A2, A3, B3, and C2 shades. Readings were obtained using VITA Easyshade V spectrophotometer for the teeth and restorations. The CIEDE2000 (ΔE00) color difference formula was used, and the values were assessed using three-way analysis of variance (ANOVA). Forty-eight evaluators graded the shade match of 32 different specimens visually as (A) best shade match, (B) intermediate shade match, and (C) poor shade match. RESULTS: FZ material achieved satisfactory matches for both thicknesses, across all shades, and OM material demonstrated statistically significant lower shade matches than the ZC and the FZ materials (p<0.05). VU exhibited poor shade match with the highest ΔE00 value on C2 shade. According to the visual examination, the best shade matches were observed for FZ on A3-shade and ZC on C2-shade teeth. CONCLUSIONS: Shade matching for 2 mm and 3 mm-thick composite resin restorations is material- and tooth-shade dependent.

The Effect of Radiotherapy on the Marginal Adaptation of Class II Direct Resin Composite Restorations: A Micro-computed Tomography Analysis.

This laboratory study was designed to evaluate the marginal adaptation of Class II mesio-occlusodistal (MOD) restorations at the cervical region with micro-computed tomography (micro-CT). Two groups of restorations were compared: 1) those that had been exposed to radiotherapy before restoration was performed using a universal adhesive in etch-and-rinse and self-etch modes; and 2) those that had previously been restored using a universal adhesive in etch-and-rinse and self-etch modes and had subsequently undergone radiotherapy. Sixty intact human molars were randomly divided into groups according to irradiation status: no radiotherapy (control group); radiotherapy followed by restoration (radiotherapy-first group); and restoration followed by radiotherapy (restoration-first group). These three groups were then subdivided into two groups each on the basis of adhesive application type (etch-and-rinse and self-etch modes), for a total of six groups (n=10/group). Standardized Class II MOD cavities were prepared. A universal adhesive (Clearfil Universal Bond Quick, Kuraray, Okayama, Japan) was applied. The teeth were restored with resin composite (Estelite Posterior Quick, Tokuyama, Tokyo, Japan). The radiotherapy protocol was conducted with 60 gray (Gy) at 2 Gy/day, five days a week for six weeks. Adhesive defects were analyzed in distal and mesial views and evaluated with micro-CT (SkyScan 1174v2, Kontich, Antwerp, Belgium) on the basis of the volume of black spaces between the cavity walls and the restorative materials (mm3). The data were analyzed using the Kruskal-Wallis, Mann Whitney U and Wilcoxon tests (p<0.05). The radiotherapy protocol did not affect the marginal adaptation of the universal adhesive at the cervical regions. Regarding the application modes, for the radiotherapy-first group, the self-etch mode caused significantly higher adhesive defects than the etch-and-rinse mode at the dentin margin. For the no-radiotherapy group, the adhesive defects at the dentin margin were significantly higher than at the enamel margin with the application of the etch-and-rinse mode.

Clinical evaluation of microhybrid composites in noncarious cervical lesions: 24-month results.

OBJECTIVE: To evaluate the clinical performance of two different microhybrid resin composites in noncarious cervical lesions (NCCLs) after 24 months. SUBJECTS AND METHODS: Ninety-seven NCCLs were restored with either TPH Spectrum (n = 48) or Filtek Z250 (n = 49) using an etch-and-rinse adhesive in 20 patients. The restorations were clinically evaluated using modified United States Public Health Service criteria for retention, color match, marginal discoloration, marginal adaptation, surface texture, anatomic form, postoperative sensitivity, and secondary caries. The restorations were assessed 1 week after placement (baseline) and after 6, 12, and 24 months. Restoration survival rates were calculated using the Kaplan-Meier procedure estimator, and a log-rank test was used to compare the survival distributions (P < 0.05). Statistical analysis was undertaken using Pearson's Chi-square test and Fisher's exact test to assess differences among the restorative materials (P < 0.05). Cochran's Q-test was employed for evaluating differences in the same restorative material between recall periods. RESULTS: The retention rates were 100% at 6 months, 89.6% and 91.8% at 12 months, and 85.4% and 89.8% at 24 months for TPH and Z250, respectively. TPH showed a statistically significant difference in marginal discoloration between the baseline and 24 months results (P < 0.05). Both TPH and Z250 showed statistically significant differences in marginal adaptation between the baseline and 24 months results (P < 0.05). CONCLUSION: Over the 24-month period, both microhybrid resin composites demonstrated acceptable clinical results in NCCLs.

Effect of laser and air abrasion pretreatment on the microleakage of a fissure sealant applied with conventional and self etch adhesives.

AIM: The purpose of this study was to investigate the effects of different pretreatment protocols along with different bonding agents on the microleakage of a fissure sealant material. METHOD: A total of 144 freshly extracted noncarious human third molars were used The teeth were randomly assigned into three groups with respect to the pretreatment protocol employed: A. Air Abrasion B. Er,Cr:YSGG laser C. No pretreatment (Control). In each group specimens were further subjected to one of the following procedures before application of the sealant: 1. %36 Phosphoric acid-etch (AE) (DeTrey Conditioner 36/Denstply, UK) 2.AE+Prime&Bond NT (Dentsply, UK) 3. Clearfil S3 Bond (Kuraray, Japan) 4. Clearfil SE Bond (Kuraray, Japan). All teeth were sealed with the same fissure sealant material (Conseal F/SDI, Australia). Sealed teeth were further subjected to thermocycling, dye penetration test, sectioning and quantitative image analysis. Statistical evaluation of the microleakage data was performed with two way independent ANOVA and multiple comparisons test at p = 0.05. For qualitative evaluation 2 samples from each group were examined under Scanning Electron Microscopy. RESULTS: Microleakage was affected by both the type of pretreatment and the subsequent bonding protocols employed (p < 0.05). Overall, the highest (Mean = 0.36 mm) and lowest (Mean = 0.06 mm) microleakage values were observed in samples with unpretreated enamel sealed by S3+Conseal F and samples with laser pretreated enamel sealed by Acid Etch+Prime&-Bond+Conseal F protocols, respectively (p < 0.05). In the acid-etch group samples pretreated with laser yielded in slightly lower microleakage scores when compared with unpretreated samples and samples pretreated with air abrasion but the statistical significance was not important (p = 0,179). Similarly, when bonding agent is applied following acid-etching procedure, microleakage scores were not affected from pretreatment protocol (p = 0,615) (intact enamel/laser or air-abrasion). For both all-in one and two step self etch adhesive systems, unpretreated samples demonstrated the highest microleakage scores. CONCLUSIONS: For the groups in which bonding agent was utilized, pretreatments did not effected microleakage. Both the tested pretreatment protocols and adhesive procedures had different effects on the sealing properties of Conseal F in permanent tooth enamel.

A conservative multidisciplinary approach for improved aesthetic results with traumatised anterior teeth.

A subgingival crown-root fracture presents a restorative problem to the clinician because restoration is complicated by the need to maintain the health of the periodontal tissues. If the remaining portion of the root is thought to be enough to support a definitive restoration, the root may be extruded by orthodontic forced eruption after root canal treatment. Extrusion enables the remaining root portion to be elevated above the epithelial attachment. Endodontic posts may be useful in exerting vertical forces to the root for extrusion without buccal tipping. The following case shows multidisciplinary management of a case of dental trauma. Orthodontic forced eruption is incorporated using endodontic posts and restoration with porcelain fused to metal crowns--leading to successful restoration of the traumatised teeth.