Quintessence International, 05/2014

Objective: To fractographically analyze the reasons for the chipping of veneering porcelain in clinically failed anterior lithium disilicate glass-ceramic (LDG) and glass-infiltrated alumina (GIA) crowns. Method and Materials: Five anterior bilayered ceramic crowns with clinical veneer chipping failure were retrieved, of which three were LDG crowns and two were GIA crowns. The fractured surfaces of the failed restorations were examined using stereomicroscopy and scanning electron microscopy (SEM). The principles of fractography were used to identify the location and dimensions of the critical crack and to estimate the stress at failure. Results: All five anterior crowns failed by cohesive failure within the veneer on the labial surface. Fractography showed that the critical crack initiated at the incisal contact area and propagated gingivally. The estimated stresses at failure for veneer chipping were lower than the characteristic strength of the veneer materials. Conclusion: Within the limitations of this in-vivo study, the contact damage, fatigue, and processing flaws within the veneer are important reasons leading to chipping of veneering porcelain in anterior LDG and GIA crowns. Keywords: ceramic restoration, failure analysis, fractography

Molar-incisor hypomineralization (MIH) is a developmental enamel hypomineralized condition characteristically involving the first permanent molars and sometimes also the incisors. The affected teeth are predisposed to tooth surface loss (TSL) which may not only compromise the esthetics and function but also endanger the pulp and longevity of the teeth. This report describes the management of a patient with MIH complicated with localized TSL and lack of occlusal clearance due to dentoalveolar compensation. The atypical TSL pattern involved all anterior teeth and required the placement of Dahl appliances on both arches. Keywords: Dahl concept, erosion, minor axial tooth movement, molar-incisor hypomineralization, tooth surface loss, tooth wear

This case report illustrates the nonsurgical endodontic management of a seven-canaled mandibular second molar. The root canal configuration presented as four mesial and three distal canals. Identification of the canal system was made with the aid of magnification, ultrasonics, and multiple angulated radiographs. Postoperative examination at 18 months showed a clinically asymptomatic tooth with resolution of the periapical pathology. Keywords: four mesial root canals, root canal anatomy, root canal nomenclature, seven root canals, three distal root canals, tooth morphology

Objective: To systematically analyze the regenerative effect of the available biomaterials either alone or in various combinations for the treatment of periodontal intrabony defects as evaluated in preclinical histologic studies. Data Sources: A protocol covered all aspects of the systematic review methodology. A literature search was performed in Medline, including hand searching. Combinations of searching terms and several criteria were applied for study identification, selection, and inclusion. The preliminary outcome variable was periodontal regeneration after reconstructive surgery obtained with the various regenerative materials, as demonstrated through histologic/ histomorphometric analysis. New periodontal ligament, new cementum, and new bone formation as a linear measurement in mm or as a percentage of the instrumented root length were recorded. Data were extracted based on the general characteristics, study characteristics, methodologic characteristics, and conclusions. Study selection was limited to preclinical studies involving histologic analysis, evaluating the use of potential regenerative materials (ie, barrier membranes, grafting materials, or growth factors/proteins) for the treatment of periodontal intrabony defects. Any type of biomaterial alone or in various combinations was considered. All studies reporting histologic outcome measures with a healing period of at least 6 weeks were included. A meta-analysis was not possible due to the heterogeneity of the data. Conclusion: Flap surgery in conjunction with most of the evaluated biomaterials used either alone or in various combinations has been shown to promote periodontal regeneration to a greater extent than control therapy (flap surgery without biomaterials). Among the used biomaterials, autografts revealed the most favorable outcomes, whereas the use of most biologic factors showed inferior results compared to flap surgery. Keywords: animal studies, histology, intrabony periodontal defects, preclinical studies, systematic review

Owing to its single surgical intervention, immediate implant placement has the advantage of shortening treatment time, and thus positively affects patient morbidity. According to the bone resorption pattern after tooth extraction, bone loss should be anticipated if immediate implant placement is considered. The present case report aims to present a possible treatment option and to demonstrate that a partially edentulous arch may be rehabilitated esthetically by immediate implant placement and by corresponding anticipatory measures. Keywords: all-zirconium oxide restoration, immediate implant placement, history of periodontitis

One of the difficult decisions confronting clinicians in daily practice is whether to treat or extract a tooth, particularly those with moderate or advanced disease processes or where trauma has inflicted substantial damage. Studies have shown that the clinician's decision is based on the length of clinical experience and the complexity of the treatment. The high survival rate of endosseous implants has also had a significant impact on the way clinicians think about the best treatment for teeth requiring endodontic therapy. Several factors should be considered when making a decision to either treat or extract a tooth. This report provides evidence-based information about the various factors and related treatment outcomes as well as clinical perceptions from a prosthodontic perspective. Keywords: extraction, implant, outcomes, retention, root canal therapy

Objective: The rehabilitation of edentulous mandibles with implant-supported overdentures is a state-of-the-art contemporary implant treatment. Computer-assisted flapless surgery is associated with decreased chairside treatment time, as well as significant reduction in patient postoperative morbidity and discomfort. The aim of this study was to evaluate the protocol of computer-guided surgery in the treatment of edentulous mandibles with overdentures supported by four intraforaminal implants and retained by Locator® attachments in elderly patients, both from a clinician's and a patient's perspective, as well as to assess the stability of the results in a 2-year period. Method and Materials: 15 patients presenting edentulous mandibles and discomfort while wearing conventional overdentures were enrolled in the study. Careful presurgical and computer-assisted 3D treatment planning was performed. Patients were treated with four intraforaminal implants using a computer-assisted flapless approach. All patients were prosthetically rehabilitated with overdentures. Clinical parameters such as peri-implant probing depth (PPD), Plaque Index (PI), and bleeding on probing (BOP) were evaluated. Patients' perceptions regarding the outcome were assessed on visual analog scales (VAS). Results: Out of 15 patients consecutively included in the study, only 10 patients could be treated with the designed protocol. A total of 40 Camlog implants were placed. No implant was lost over a 2-year period. BOP was negative in 82% of sites; mean PPD was 2.34 mm; 8 of the 40 implants showed the absence of keratinized tissue on the lingual or the vestibular aspect. The VAS score of 9.9 demonstrated the satisfaction of the patients. Conclusions: Within the limitations of this study, the data demonstrate that in a significant number of cases this protocol could not be used for anatomical or technical reasons. In the cases where it could be used, the computer-assisted protocol appeared suitable for treating elderly patients with mandibular edentulism and restoring them with an overdenture in a minimally invasive way. The possibility of placing implants outside the borders of the keratinized tissue is relevant. Keywords: flapless surgery, guided surgery, overdenture

Necrotizing sialometaplasia (NS) is a rare and benign lesion that mostly affects the posterior hard palate. Its importance resides in its clinical and microscopic characteristics, which can closely mimic malignant neoplasias, in particular oral squamous cell carcinoma and mucoepidermoid carcinoma. Accurate histopathologic evaluation of an incisional biopsy is considered as the diagnostic gold standard. NS lesions heal spontaneously within weeks, and no further treatment is necessary. We report a case of a bilateral palatal NS in a 22-yearold woman with bulimia, where an incisional biopsy confirmed the clinical diagnosis. The different clinical stages of the lesions from onset to resolution and the possible etiologic factors are described in detail, as well as a discussion of the differential diagnoses of palatal ulcers. When taking a biopsy from suspicious oral lesions, care has to be taken that an appropriate tissue sample is harvested, and the histopathologic analysis is performed by an experienced pathologist to establish a correct diagnosis. Keywords: biopsy, bulimia nervosa, eating disorders, minor salivary glands, necrotizing sialometaplasia, oral ulcers

Objective: The aim of this study was to examine the association between black extrinsic tooth discoloration and caries prevalence in an adult population. This association has been previously shown in children and adolescents but has never been examined in an adult population. Method and Materials: Young adults, aged 18 to 29 years old, were examined for black extrinsic tooth discoloration and caries prevalence. The study group included 110 young adults with black stain; the control group consisted of 170 young adults without black stain. The decayed, missing, or filled teeth (DMFT) index score was determined for each subject. The mean DMFT score was calculated for both groups and compared between groups (independent t test). Multiple logistic regression analysis was applied to identify independent influences (age, pigmentation, gender, and smoking) on DMFT. Results: Mean DMFT score was 4.2 ± 3.9 for the study group and 5.98 ± 4.8 for the control group, which was statistically significant (P < .001). Mean D score (untreated caries) was 1.6 ± 2.5 (study) and 2.4 ± 3.5 (control) (P < .05). Age had a positive correlation with the DMFT score; however, gender and smoking were negatively correlated. Conclusion: The association between black stain and reduced rates of dental caries was demonstrated in a young adult population for the first time. Keywords: black stain, caries prevention, DMFT index, extrinsic tooth discoloration