Quintessence International, 01/2016

Bonded porcelain restorations are a predictable and durable treatment option that can restore not only the strength and function of the teeth but also the esthetic appearance. One important issue in adhesive dentistry is the preservation of sound enamel. Following biomimetic principles, employing minimally invasive applications and adhesive technologies is of paramount importance for successful restorations. While it is widely accepted that minimally invasive restorative techniques should be favored, there is still some controversy over the noninvasive approaches. The purpose of this article is to question the complete "no-prep veneer" concept due to the possible negative effects on periodontal health caused by excessive contour and overhangs of the ceramic restoration, and to propose a new method to assess the quality and longevity of veneers with a partial-prep concept. Keywords: adhesive luting, biomimetic principles, bonded porcelain restorations, esthetic, minimally invasive treatment modalities, scanning electron microscopy

Objective: Several studies demonstrate variability of root canal morphology of anterior teeth. This in-vivo study was designed to analyze and characterize root canal morphology of maxillary and mandibular anterior teeth using three-dimensional imaging. Method and Materials: Patients who required CBCT radiographic examinations as part of their routine examination, diagnosis, and treatment planning were enrolled on the study. A total of 1,200 healthy, untreated, fully developed maxillary and mandibular incisors and canines were included. The following observations were recorded: (i) number of roots and their morphology; (ii) number of canals per root; and (iii) primary variations in the morphology of the root canal systems. Results: Root canal morphology of maxillary teeth was consistent with a single canal extending from the pulp chamber to the apex in 98% of the cases. In contrast, in mandibular central and lateral incisors, the presence of a single canal represented 64.5% and 60.5% respectively. The second most common morphology was the presence of one canal leaving the pulp chamber, which divided into two within the root, and then merged to exit as one canal in 18% and 25.5% respectively. The presence of one canal leaving the pulp chamber and dividing short of the apex into two separate and distinct canals with separate apical foramina (variant 5) was recorded in 14.5% and 12% respectively. Conclusion: There was a low incidence of anatomical variation in maxillary anterior teeth. In contrast, mandibular anterior teeth presented with a high prevalence of two canals, especially central and lateral incisors. The reported data may help clinicians understand the variations in root canal morphology of anterior teeth in order to overcome problems associated with shaping and cleaning procedures. Keywords: anterior teeth, CBCT, morphology, root canal anatomy

Objective: The improvement in diagnostic accuracy and optimization of treatment planning in periodontology through the use of three-dimensional imaging with cone beam computed tomography (CBCT) is discussed controversially in the literature. The objective was to identify the best available external evidence for the indications of CBCT for periodontal diagnosis and treatment planning in specific clinical situations. Data Sources: A systematic literature search was performed for articles published by 2 March 2015 using electronic databases and hand search. Two reviewers performed the study selection, data collection, and validity assessment. PICO and PRISMA criteria were applied. From the combined search, seven studies were finally included. Conclusion: The case series were published from the years 2009 to 2014. Five of the included publications refer to maxillary and/or mandibular molars and two to aspects related to vertical bony defects. Two studies show a high accuracy of CBCT in detecting intrabony defect morphology when compared to periapical radiographs. Particularly, in maxillary molars, CBCT provides high accuracy for detecting furcation involvement and morphology of surrounding periodontal tissues. CBCT has demonstrated advantages, when more invasive treatment approaches were considered in terms of decision making and cost benefit. Within their limits, the available data suggest that CBCT may improve diagnostic accuracy and optimize treatment planning in periodontal defects, particularly in maxillary molars with furcation involvement, and that the higher irradiation doses and cost-benefit ratio should be carefully analyzed before using CBCT for periodontal diagnosis and treatment planning. Keywords: cone beam computed tomography, decision making, diagnosis, furcation involvement, furcation surgery, regenerative periodontal surgery, three-dimensional imaging

Objectives: The objective of this prospective study was to compare the clinical outcomes of coronally advanced flap (CAF) using two different surgical strategies in the treatment of multiple gingival recessions. Method and Materials: Ten patients presenting with a total of 81 Miller class I gingival recessions were included. Recessions were randomly treated according to a split-mouth design by means of CAF with oblique interdental incisions (OBL technique), or CAF with horizontal interdental incisions (HOR technique). Marginal gingival recession (REC), clinical attachment level (CAL), pocket probing depth (PPD), height of keratinized tissue (HKT), and thickness of keratinized tissue (TKT) were measured at baseline, and 3 and 6 months after treatment. Patient-centered outcomes concerning morbidity and improvement in the esthetic appearance were recorded using a visual analog scale (VAS). Results: Both groups showed significant reductions in REC and gains in CAL throughout the study (P < .05). At 3 months, OBL-treated sites showed greater root coverage than HOR-treated sites (P < .05), although no intergroup differences were observed at 6 months (P > .05). There was an increase in HKT only in the OBL group at 6 months from baseline (P < .05). No differences between therapies were revealed concerning morbidity (P > .05), whereas a higher satisfaction with the esthetic appearance was reported for the OBL technique 6 months postsurgery (P < .05). Conclusion: Although both surgical approaches may provide satisfactory root coverage, use of the OBL technique promoted additional benefits in terms of esthetic perception after the management of multiple gingival recessions. Keywords: controlled clinical trial, gingival recession, operative, patient outcome assessment, surgical procedures

Objective: The aim was to compare two measurements of lower facial height (base of chin-subnasale and base of chin- tip of the nose) as related to different anthropometric measurements in dentate and completely edentulous subjects. Method and Materials: This cross-sectional study was conducted on 132 male subjects (group 1 [G1], 120 dentate subjects; and group 2 [G2], 12 completely edentulous subjects). Base of chin-subnasale measurement (FM1), base of chin-tip of the nose measurement (FM2), Willis' measurement (FM3), glabella-subnasale measurement (FM4), length of the index finger measurement (AM1), and tip of thumb-tip of index finger measurement (AM2) of subjects of G1 and G2 were measured by using a modified caliper while the subjects in G1 closed in centric occlusion, and the subjects of G2 were asked to close the maxillary and mandibular complete dentures in centric relation. Statistical analysis was carried out by using paired t test, Pearson's correlation (PC), and regression analysis. Results: There were no significant differences between G1FM1 and G1FM3, G1FM1 and G1FM4, G1FM1 and G1AM2 (P > .05), and PCs were R = 0.74, R = −0.35, and R = −0.32 respectively. However, there were significant differences between G1FM2 and G1FM3, G1FM2 and G1FM4, G1FM2 and G1AM2 (P ≤ .05), and there were significant differences between G2FM2 and different measurements of G2 (P ≤ .05). Conclusion: The use of the linear equation to predict the possible base of chin-subnasale measurement through the Willis' measurement was recommended and could be used as a guide during restoration of the vertical dimension of occlusion when it has been lost. Keywords: anthropometric measurements, complete denture, edentulous, facial measurements, vertical dimension of occlusion

Objective: The present study investigated how a hybrid light source (LED/laser) influences temperature variation on the enamel surfaces during 35% hydrogen peroxide (HP) bleaching. Effects on the whitening effectiveness and tooth sensitivity were analyzed. Method and Materials: Twenty-two volunteers were randomly assigned to two different treatments in a split-mouth experimental model: group 1 (control), 35% HP; group 2 (experimental), 35% HP + LED/laser. Color evaluation was performed before treatment, and 7 and 14 days after completion of bleaching, using a color shade scale. Tooth sensitivity was assessed using a visual analog scale (VAS; before, immediately, and 24 hours after bleaching). During the bleaching treatment, thermocouple channels positioned on the tooth surfaces recorded the temperature. Data on color and temperature changes were subjected to statistical analysis (α = 5%). Tooth sensitivity data were evaluated descriptively. Results: Groups 1 and 2 showed mean temperatures (± standard deviation) of 30.7 ± 1.2°C and 34.1 ± 1.3°C, respectively. It was found that there were statistically significant differences between the groups, with group 2 showing higher mean variation (P < .0001). The highest temperature variation occurred for group 2, with an increase of 5.3°C at the enamel surface. The color change results showed no differences in bleaching between the two treatment groups (P = .177). The variation of the average temperature during the treatments was not statistically associated with color variation (P = .079). Immediately after bleaching, it was found that 36.4% of the subjects in group 2 had mild to moderate sensitivity. In group 1, 45.5% showed moderate sensitivity. In both groups, the sensitivity ceased within 24 hours. Conclusion: Hybrid light source (LED/ laser) influences temperature variation on the enamel surface during 35% HP bleaching and is not related to greater tooth sensitivity. Keywords: color, dental bleaching, dental enamel, laser, tooth sensitivity, temperature

Rotating instruments used in the fields of dentistry and oral surgery operate at high speeds. Therefore, if small particles are projected and strike the orbit, injuries of varying severity can occur. We report here a case in which a broken dental bur pierced into the orbit. The bur fortunately did not damage the eyeball and stopped after penetration of the medial orbital wall. The subject was a 27-year-old dental assistant and not wearing protective eyewear. A foreign body had penetrated the medial wall of the right orbit and the tip had reached the ethmoid sinus. The medial orbital wall was exposed subperiosteally after dissection of the medial canthal ligament, and the foreign body was removed. Although the importance of protective eyewear had been advocated, eye protection compliance differed by region and dental personnel. Eye protection use needs to increase in not only dentists but also other dental personnel. Keywords: broken dental bur, eye protection, foreign body, occupational hazard, ocular injuries, orbital wall