Quintessence International, 03/2013

Diastema closure is a frequently requested, technique-sensitive cosmetic procedure. There are many techniques and materials that can be employed to close diastemas. While direct composite techniques can be economical and successful, they do present challenges in achieving satisfactory clinical and esthetic results. Traditional porcelain veneer placement may offer an excellent esthetic result, but typically requires the removal of tooth structure; as such, this is an irreversible procedure. The present article reports the case of a maxillary midline diastema closure in a healthy dentition by means of sectional porcelain veneers simply cemented onto the natural teeth and without tooth preparation. A step-bystep procedure is proposed for illustrating the proper implementation of an additive-only and noninvasive indirect technique that yields a satisfactory clinical and esthetic outcome for clinician and patient. Keywords: adhesion, diastema, diastema closure, esthetic dentistry, porcelain veneer, sectional veneer

Objectives: Temporary restorative materials (TRMs) often rapidly lose their dimensional stability and antibacterial properties after exposure to humidity and bacterial infection. Quaternary ammonium polyethyleneimine (QPEI) nanoparticles (NP) are long-lasting, stable, biocompatible, and nonvolatile antibacterial polymers. In the present study, we incorporated QPEI NP into standard TRMs and examined their influence on dimensional stability and their ability to reduce bacterial leakage. Method and Materials: A modified split-chamber model was used in vitro to test calcium sulfate-based and zinc oxide-eugenol- based TRMs (Coltosol and IRM, respectively). Both materials were tested with and without 2% wt/wt incorporated QPEI NP for fluid and bacterial leakage. Results: The calcium sulfate-based TRM displayed the lowest microleakage and highest antibacterial resistance. Two-way A NOVA analysis of the fluid transport test results showed that incorporation of 2% wt/wt QPEI NP significantly increased the sealing ability of both TRMs (P .01). A nalysis of survival curves by the Kaplan-Meier method showed that the calcium sulfate-based TRM with 2% wt/wt QPEI NP survived the bacterial load significantly more effectively than did the zinc oxide-eugenol-based TRM (P .0001). Conclusion: Incorporation of 2% w/w QPEI NP may prominently improve the sealability and the antibacterial properties of TRMs. TRMs incorporating antibacterial nanoparticles may be clinically advantageous for sealing the endodontic access cavity to avoid reinfection of the root canal system during endodontic treatment. Keywords: nanoparticles, polyethyleneimine, temporary restorative materials

Objective: The aim of this randomized controlled clinical trial was to investigate the antimicrobial efficacy of traditional positive pressure (PP) irrigation compared with apical negative pressure (ANP) in tapered as well as non-tapered root canal preparation techniques. Method and Materials: Patients referred for treatment of mandibular permanent molars with necrotic pulps and apical periodontitis were considered for this study. A total of 32 eligible teeth were evaluated based on strict inclusion and exclusion criteria and randomly assigned as follows: Group 1: LightSpeed LSX 0.02 preparation and A NP irrigation (n = 8). Group 2: LightSpeed LSX 0.02 preparation and PP irrigation (n = 8). Group 3: ProTaper preparation and A NP irrigation (n = 8). Group 4: ProTaper preparation and PP irrigation (n = 8). A ll teeth were sampled immediately upon access (S1), after completion of the chemo- mechanical preparation (S2), and one week later after intracanal medication (S3). All samples were microbiologically processed immediately and plated in duplicates on aerobic plates, anaerobic plates, and chocolate plates and colonies statistically analyzed. Results: No statistically significant differences were found between groups at S1. When comparing colony-forming unit (CFU) levels at S1 and S2 within groups, the reduction was statistically significant in all groups. While no significant difference was found in the proportion of teeth that culture positive at either S2 or S3 by shaping groups, a significant difference was noted when comparing PP irrigation and A NP groups. The percentage of samples in the PP irrigation group with a negative culture at both time points was 67%, compared to 100% among the A NP group. Conclusion: Within the limitations of the present study, taper and apical size failed to demonstrate a difference in microbiological reduction of cultivable bacteria. On the other hand, A NP revealed a significant difference when compared to PP irrigation. Keywords: apical negative pressure, apical periodontitis, irrigation, root canal disinfection

Objective: This randomized clinical study examined the use of hyaluronic acid to treat infrabony periodontal defects over a period of 24 months. Method and Materials: Forty subjects with a two-wall infrabony defect (probing depth [PD] >= 7 mm; clinical attachment level [CAL] >= 7 mm) were selected. The defects were randomly divided into two groups: sites treated with hyaluronic acid (test group) and those treated with open flap debridement (control group). Results: The 12- and 24-month evaluations were based on clinical and radiographic parameters. The primary outcome variable was CAL. Test defects shows a mean CAL gain of 1.9 ± 1.8 mm, while the control defects yielded a significantly lower gain of 1.1 ± 0.7 mm. PD reduction was also significantly higher in the test group (1.6 ± 1.2 mm) than in the control group (0.8 ± 0.5 mm). Frequency distribution analysis of the study outcomes indicated that hyaluronic acid increased the predictability of clinically significant results (CAL gains >= 2 mm and PD reduction >= 2 mm) in the test group compared with the controls. Conclusions: The treatment of infrabony defects with hyaluronic acid offered an additional benefit in terms of CAL gain, PD reduction, and predictability compared to treatment with open flap debridement. Keywords: hyaluronic acid, infrabony periodontal defect, periodontal disease, periodontal regeneration, randomized clinical trial

Objective: To study the clinical applicability of porcine dermal matrix for treatment of recession type defects. Method and Materials: Twenty-eight gingival recessions in six patients were selected for root coverage procedures using a modified tunneling technique and porcine dermal matrix. As primary outcome, depth and width of gingival recession were assessed at baseline and at 6 and 12 months postoperatively. As a secondary outcome, the width of keratinized tissue was studied. Results: At 6 and 12 months postoperatively, mean root coverage was 65.52% and 56.82%, respectively. Complete root coverage was achieved in 42.86% of the treated defects. Conclusion: Porcine dermal matrix may potentially be used as a replacement material for autologous tissue. However, complete root coverage was only achieved in less than half of the studied defects. Keywords: porcine dermal matrix, root coverage, tunneling technique

Objectives: Etiological periodontal therapy is effective in reducing cyclosporin A-induced gingival overgrowth, but a high variability among subjects has been observed. This study aimed to evaluate the role of polymorphisms in PAI-1 and A BCB1 genes on the course of this side effect following periodontal therapy. Method and Materials: Forty-five transplant patients were subjected to nonsurgical periodontal therapy and evaluated for hypertrophy index, probing depths, bleeding, and plaque scores at baseline, and after 3 and 6 months. A BCB1 (C3435T and G2677T) and PAI-1 (4G/5G) polymorphisms were studied with polymerase chain reaction-restriction fragment length polymorphism and allele-specific polymerase chain reaction respectively. Results: All the monitored periodontal indexes decreased significantly during the six months. Modeling of hypertrophy index by linearmixed- effect models (allowing non-normal distribution of the outcome variable hypertrophy index) resulted in the selection as the most significant model, of the one comprising the independent variables: time, C 3435T genotype, and their interaction term. This model indicated that C 3435T-mutated patients had significantly higher baseline hypertrophy index values (90% Markov chain Monte C arlo empirical confidence intervals: 5.08, 30.00). The decrease in hypertrophy index values over time showed a trend toward being faster in mutated than nonmutated patients (interaction time: C 3435T nonmutated, 90% Markov chain Monte C arlo empirical confidence interval: -11.08, -0.40). When hypertrophy index values were normalized, the significance and trend were lost. No effect of the A BCB1 G2677T and PAI-1 4G/5G polymorphisms was observed. Conclusion: These preliminary results suggest that C 3435T polymorphism is a genetic factor that could influence the course of cyclosporin A-induced gingival overgrowth in transplant patients subjected to periodontal therapy. Keywords: ABCB1 gene, gingival overgrowth, PAI-1 gene, polymorphism

Objectives: It was the purpose of this finite element analysis to compare the implant-restoration connection created by Procera Implant Bridge (PIB) and conventional screw-retained prostheses with respect to screw loading and gap formation. Method and Materials: Finite element models representing a conventional screw-retained restoration and a PIB were set up. A horizontal load of 200N was applied on the restorations while resulting gap formation and screw loading was recorded. Results: Increasing the preload of the retaining screws led to a decrease in gap formation. Smaller gaps were observed in the conventional restorations. Loading of the screws was of comparable magnitudes in both cases. Conclusion: The use of screw-retained implant-supported restorations representing butt-joint connections at the restorative interface may result in increased gap formation. Keywords: gap formation, implant-abutment interface, Procera Implant Bridge, screw joint stability

Objectives: Oropharyngeal cancer (OPC) is the sixth most common cancer worldwide. Focus on risk factors, improved diagnostic methods and effective management strategies have made it possible to successfully treat OPC. However, the 5-year survival rate has not improved for several years due to multiple treatment complications, tissue morbidity, loss of function, and diminished quality of life. Survivors are faced with complications like oral mucositis, hyposalivation, osteoradionecrosis, tissue fibrosis, morbidity from jaw resection, disfigurement, and loss of function that further diminish quality of life. The aim of this review is to highlight major complications associated with treatment of OPC via a literature search and review of available options for identification and management of these complications. Data sources: Relevant publications on oral complications of OPC therapy were thoroughly reviewed from the literature published between the years 1988 and 2012. We evaluated reported incidence, prevalence, and risk factors for oral complications of chemotherapy and radiotherapy for OPC. The authors conducted an electronic search using English language databases, namely PubMed Plus, Medline (Pre-Medline and Medline), Cochrane Database of Systematic Reviews (evidence-based medicine), Dentistry & Oral Sciences Source, A ccessScience, Embase, Evidence-Based Medicine Reviews Multifile, Google Scholar, ISI Journal Citation Reports, and Ovid Multi-Database. Conclusion: We identified the most common complications associated with the treatment of oral cancers. Based on the information gathered, there is evidence that survival of OPC extends beyond eradication of the diseased tissue. Understanding the potential treatment complications and utilizing available resources to prevent and minimize them are important. Caring for OPC survivors should be a multidisciplinary team approach involving the dentist, oncologist, internist, and social worker to improve the currently stagnant 5-year survival rate of OPC. More emphasis on improved quality of life after elimination of the cancer will ultimately improve OPC survivorship. Keywords: cancer, chemotherapy, complications, osteoradionecrosis, radiotherapy, xerostomia