Quintessence International, 06/2007

This article describes a minimally invasive technique to treat a severe case of enamel fluorosis using microabrasion to eliminate the hypermineralized, white-colored, superficial enamel layer, followed by home bleaching treatment and chairside re-creation of superficial enamel microstructure. The proposed technique may improve the esthetics of fluorotic teeth without requiring other restorative procedures. Microabrasion followed by home bleaching may be an interesting alternative for the restorative treatment of teeth affected by fluorosis. Keywords: fluorosis, microabrasion, micromorphology, minimally invasive treatment

Objective: To determine the caries and fluorosis prevalence of adolescents in 3 communities in Iran with varying urbanization and concentrations of fluoride in the piped water. Method and Materials: Data were obtained from 593 examinations of 12- and 15-year-olds in Tehran (water fluoride concentration: 0.3 mg F/L), the city of Semnan (1.3 mg F/L), and the village Dibaj (0.2 mg F/L) in Iran. Results: In both age groups, comparable counts of decayed, missing, and filled surfaces (DMFS) were observed, whereas the values related to teeth (DMFT [SD]) were significantly higher in 12-year-olds from Semnan (1.5 [1.8]) than those for children from Dibaj (0.7 [1.0]) (P .05; Mann-Whitney test) but comparable to those for children in Tehran (1.2 [0.7]). A lower prevalence of dental restorations was reported for both Semnan and Dibaj (Unmet Restorative Index [UNT]: 67% to 82%) compared to Tehran (15% to 39%). In Semnan, the risk of having medium to severe fluorosis was 10- and 34-fold compared to Tehran and Dibaj, respectively. Conclusions: Caries prevalence was relatively low compared to that in other countries in the Middle East. In the examined population, which was not adjusted to socioeconomic status, naturally fluoridated water seemed to have no obvious effects on DMFT, but resulted in an esthetically relevant higher prevalence of dental fluorosis. Keywords: caries prevalence, fluorosis prevalence, epidemiology, Iran, Middle East, water fluoridation

Objective: To evaluate the flow rate, amylase and peroxidase activities, and total protein and sialic acid concentrations in saliva of adolescents with cerebral palsy. Method and Materials: The saliva of 24 adolescents with cerebral palsy was compared with that of 18 adolescents without cerebral palsy, all aged around 12 years, 2 months. The whole saliva was collected under slight suction and frozen at -80°C. Flow rate, amylase and peroxidase activities, and total protein and sialic acid concentrations were analyzed by standard methods. Results: The flow rate was low in the cerebral palsy group. The cerebral palsy group demonstrated low amylase and peroxidase activities. Boys and girls from the cerebral palsy group demonstrated higher total protein concentration than the boys and girls from the control group. Sialic acid, free and total, concentration was higher in the cerebral palsy group than in the control group. Conclusion: The results suggest that adolescents with cerebral palsy present alterations in the salivary parameters studied that can increase the risk of oral disease in this population. Keywords: adolescent, amylase, cerebral palsy, peroxidase, saliva, sialic acid

The occurrence of epidermoid cysts in the oral cavity is extremely rare. These cysts generally present slow and progressive growth and often are not diagnosed until the second or third decade of life. Epidermoid and dermoid cysts in the floor of the mouth are painless, doughy or fluctuant lesions and cause no symptoms until they are large enough to interfere with speech or eating. This article presents the case of a 20-year-old man with swelling in the floor of his mouth that was causing difficulties with speech and swallowing. After surgical removal of the cyst, histopathologic examination confirmed the diagnosis of epidermoid cyst. Characteristics of epidermoid cysts are described and surgical treatment discussed. Keywords: dermoid cyst, epidermoid cyst, floor of the mouth, sublingual, swelling

Objectives: To compare the surface detail reproduction ability of 2 polyethers, 1 polyether-polyvinyl siloxane (PVS) hybrid, and 1 polyvinyl siloxane reference impression material when impressions of prepared dentin are made, and to determine the wettability of the nonset and set impression materials. Method and Materials: Impressions from air-dried or wet dentin surfaces were made with the light-bodied impression materials P2 Polyether (P2L), Impregum Garant L DuoSoft (IMP), the hybrid-type Fusion/Senn Light (SEN), and the PVS Flexitime Correct Flow (FLE). Roughness (Rz, Ra) was determined on 5 dentin specimens and 5 impressions (dry or wet) for each material. Data were analyzed using ANOVA and Duncan's test (a .05). Wettability with water of nonset and set impression materials was recorded with an optical contact-angle measuring device. The set materials' wettability was determined on dry surfaces and after rinsing with water. Results: Differential dentin surface reproduction with IMP, SEN, and FLE was between -2 and +2 µm (Rz), and -0.2 and +0.2 µm (Ra). Curing of P2L on dentin was inhibited. The contact angle of nonset IMP was less than 45 degrees, and initial angles for nonset SEN, FLE, and P2L were greater than 90 degrees. Early contact angles on rinsed FLE, P2L, and SEN were greater than 90 degrees. Angles on set IMP were consistently between initial 75 degrees and final 55 degrees. Conclusion: IMP, SEN, and FLE reproduce prepared dentin accurately, whereas P2L does not cure on dry or wet dentin. All materials have a reasonable potential of wetting moist surfaces. Keywords: contact angle, impression material, polyether, surface detail reproduction, polyvinyl siloxane, wettability

Objective: Since fine-motor movements and complex procedures, which are often necessary in dental practice, can be compared to those used by professional athletes, the purpose of this study was to determine the impact of the mental training technique, established in sport science, on dentistry. Method and Materials: In a randomized, controlled study, 2 groups of 20 and 21 dental students in their second semester (experimental group with mental training, and control group with conventional training, respectively), were evaluated at 2 time points (pre- and posttest) by measuring the effect of training by the criteria "knowledge," "process," and "quality" of a crown preparation on the computer-assisted Dental-Simulator (DenX). Results: The improvements of the experimental group and of the control group from pre- to posttest could be distinguished for all criteria in favor of the experimental group, in which improvements of knowledge (F1,39 = 72.674, P .001) and process (F1,39 = 6.63, P = .01) were statistically significantly better. Conclusion: The significantly greater improvements of the experimental group regarding knowledge and process compared to the control group indicate that the improvement in learning and performance caused by mental training is detectable in dental education, especially with regard to cognitive aspects of dental procedures. Keywords: crown preparation, dental education, learning method, mental training, randomized controlled trial, tooth preparation

Patients who require restorative intervention in the anterior teeth expect esthetics to be integrated with other teeth that compose the smile. Therefore, not only should clinicians have a scientific technique for restoration of dental biology and function, but also their esthetic sense should direct them in the reproduction of polychromatic and anatomic characteristics of the tooth, rendering the restoration imperceptible. The introduction of new resin composites with better mechanical and optical properties, combined with better understanding of the optical behavior of dental tissues, has allowed a more artistic approach for accomplishment of direct bonded restorations with resin composite. Reproduction of optical behavior characteristics in restorations requires proper interpretation of shade variations, with use of resources and effects with resin composite to allow correspondence with the tooth substrates, and correct use of resin composite at the proper place and of exact thickness. This article describes, with the aid of a case report, a technique for shade selection and choice of resin composites. Moreover, a clinical sequence for application of resin composites is presented that allows reproduction of the interaction between tooth structures and light in proximoincisal restorations. With this technique, the restorative procedure achieves a satisfactory and predictable final esthetic outcome. Keywords: hue, opacity, opalescent halo, proximoincisal restorations, resin composite, shade, shade selection, translucency

Objective: To compare the failure rate of posterior interproximal amalgam restorations to resin-based composite restorations in a random young adult population. Method and Materials: Bilateral bitewing radiographs of 459 young adults were screened. A total of 14,140 interproximal surfaces were examined, recorded, and statistically analyzed. Rate of failure was determined by the number of restorations with radiographic evidence of secondary caries and/or overhanging margins. Results: Of the 650 restored interproximal surfaces (5% of all clearly demarcated interproximal surfaces), 86 (13%) demonstrated distinct interproximal secondary caries and 22 (3%) had overhanging margins. Of the 557 amalgam and 93 resin-based composite interproximal restorations, secondary caries were shown in 46 (8%) and 40 (43%), respectively, and overhanging margins in 21 (4%) and only 1 (1%), respectively. Generally, when secondary caries and overhanging margins were considered, the failure rate of amalgam and resin-based composite interproximal restorations was 12% and 44%, respectively. Conclusions: Higher failure rates were observed in resin-based composite restorations than in amalgam restorations. Secondary caries was the main reason for failure. Overhanging margins were not a primary factor in restoration failure. The vast use of posterior interproximal resin-based composite restorations should be reconsidered, and their limited long-term performance should be kept in mind. Keywords: amalgam, bitewing radiograph, failure rate, interproximal posterior restorations, resin composite

Mucormycosis is a rare acute opportunistic infection caused by a saprophytic fungus, which belongs to the order Mucorales. This report describes intraoral mucormycosis in 2 children with acute leukemia who were undergoing chemotherapy and had febrile neutropenia. A 7-year-old boy with acute myeloid leukemia and a 9-year-old boy with acute lymphoblastic leukemia were referred to the Department of Pediatric Dentistry at Cukurova University for their intraoral soft tissue lesions, which were diagnosed as mucormycosis by histologic examination. While, for the first case, the lesion was debrided under general anesthesia and medical antifungal therapy was performed, only medical management was done, without any debridement, for the second case. Early recognition of mucormycosis is necessary to limit the spread of infection, which can lead to high morbidity and mortality. Therefore, health practitioners should be familiar with the signs and symptoms of the disease. Keywords: children, gingiva, hyperplasia, leukemia, mucormycosis

Odontomas are developmental malformations of dental tissues, and they may interfere with the eruption of the associated tooth. Odontomas have limited growth potential, and their occurrence in the primary dentition is uncommon. This article describes a case of a large complex odontoma in a 5.2-year-old boy that prevented eruption of the mandibular left lateral incisor. The odontoma was surgically removed, routine follow-up was done for more than a year, and no recurrence was seen. Keywords: anterior mandible, complex odontoma, mixed tumor, odontogenic tumor, opaque lesion, primary tooth

Objective: The purpose of this investigation was to test the microleakage of 3 porcelain repair systems intended for intraoral resin-to-porcelain and resin-to-metal bonding by autoradiography. Method and Materials: Sixty alloy and 60 porcelain disks (10-mm diameter and 2-mm thickness) were prepared. Manufacturer's directions were followed for surface treatment of specimens. Each repair material was applied on 20 alloy specimens and 20 porcelain specimens. Specimens were thermocycled by dipping them in water for 1 minute at 4 ± 2°C and 58 ± 2°C for 500 cycles. Leakage was demonstrated by the presence of radioactive isotope at the interface between the repair material and the alloy (or porcelain) as registered by autoradiography. Before testing, specimens were stored in distilled water at 37°C for 24 hours and then thermocycled. Mann-Whitney U test was used to identify the differences. Results: For the alloy groups, differences between Newbond/Clearfil Lustre and GoldLink 2/Ultrabond were significant (P .05). For the ceramic groups, differences between Cerinate Prime/Ultrabond, Clearfil Lustre/Newbond, Cerinate Prime/Ultrabond, and Silibond/Charizma were significant (P .05). Conclusions: For the porcelain groups, the amount of microleakage in Ultrabond/Cerinate Prime was significantly higher than the other groups. For the alloy groups, all samples showed leakage. Keywords: alloy, autoradiography, composite, intraoral repair, microleakage, porcelain repair materials

The objective of this study was to compare strain magnitudes around implants supporting ball-retained, bar-retained, and distal cantilevered bar-retained mandibular overdentures subjected to vertical and oblique loads. Twelve edentulous mandibular acrylic resin casts with 2 implants in the parasymphyseal region were randomly divided into 3 groups (n = 4). Ball-retained, bar-retained, and distal cantilevered (8 mm) bar-retained overdentures were fabricated. A linear strain gauge was bonded distal to each supporting implant on the surface of the cast. As static loads of 20, 40, and 60 N vertically were applied 20 degrees obliquely and unilaterally to the overdenture, the generation of strains was recorded by a data acquisition system and corresponding software at a sample rate of 1,000 Hz. The absolute strain data of each group were compared within each loading condition by Kruskal-Wallis test followed by post hoc tests (a = .05). Under vertical and oblique loading conditions, strain magnitudes around implants supporting ball-retained overdentures were higher than those induced around bar-retained and distal cantilevered bar-retained overdentures (P .01). On the contralateral side from load application, strains around implants supporting ball-retained overdentures were lower than those around bar-retained and distal cantilevered bar-retained overdentures (P .01). Force distribution does not occur for implants supporting ball-retained overdentures, and such implants are subjected to more load than those supporting bar-retained and distal cantilevered bar-retained overdentures. Keywords: Dental implants, overdenture, biomechanics, strain gauge

Objectives: This ongoing prospective study evaluates the clinical performance of an ORMOCER restorative material (Definite; Degussa) in combination with a self-conditioning adhesive (Etch & Prime 3.0; Degussa). Method and Materials: Three hundred fifty-six restorations (48 Class I, 150 Class II, 63 Class III, 32 Class IV, and 63 Class V) in 117 patients (17 to 65 years) were placed by 5 operators at 5 centers. Fillings were placed with cotton roll isolation using clear matrix bands for Classes III and IV and metal matrix bands for Class II restorations. Follow-ups took place after 6, 12, and 24 months whereby modified Ryge criteria were recorded. With 33 randomly selected Class I and II restorations, measurements of occlusal wear (3-dimensional laser scanner) and marginal analyses (scanning electron microscope) were done using replicas. Results: At 24 months, 307 restorations were available for evaluation. The cumulative number of losses in the 5 cavity classes (I, II, III, IV, and V) and the percentages of scores for the clinical parameters in the 4 categories (Alfa, Beta, Charlie, and Delta) of the retained restorations were loss (1/ 6/ -/ 2/ 7), marginal integrity (93.1/ 6.9/-/-), marginal discoloration (73.5/ 25.5/ 1/ -), anatomic form (82.8/17.2/-/-), and fracture (93.1/ 6.9/-/ -). Marginal analysis showed 48.7% "continuous margin" initially and 13.2% at 24 months (difference statistically significant, a = 0.05). Occlusal wear at 24 months was 12.3 µm for premolars and 21.4 µm for molars. Conclusions: The overall clinical performance of the ORMOCER restorative over 24 months was acceptable with concerns related to marginal quality and to retention of Class V restorations. Keywords: clinical trial, resin composite, restorative material, self-etching dental adhesive

Objective: The purpose of this study was to evaluate the frequency of positive radiographic findings in panoramic radiographs of edentulous arches. Method: A sample of 327 panoramic radiographs was selected from the patient pool at the University of Oklahoma College of Dentistry. Radiographs were evaluated for presence of retained root tips, impacted teeth, radiolucent and radiopaque areas, soft tissue calcifications, and foreign bodies. Results: Approximately 57.5% of panoramic radiographs revealed no positive radio-graphic findings, while the remaining 42.5% contained 1 or more positive radiographic findings. Thirty-nine root fragments were identified, and the majority were located in the maxilla. However, only 5 pathological findings (3.8%) required treatment modification before denture fabrication. Conclusions: Results of the study do not support routine pretreatment panoramic radiography on patients seeking denture fabrication. Panoramic radiography is a valuable diagnostic tool in the pretreatment assessment of partially and completely edentulous patients, but their routine use in such patients should be discouraged. Keywords: dental, edentulous, edentulous patients, panoramic, positive radiographic findings, radiology

This article reports the evaluation of the therapeutic effect of a palatal lift prosthesis with a specially designed connection between the anterior denture base and the palatal lifting plate in a patient with velopharyngeal incompetence due to severe brain injury. Keywords: articulatory function, brain injury, dysarthria, nasality, palatal lift, prosthesis, velopharyngeal incompetence

Objective: The aim of this investigation was to evaluate the effect different cleaning techniques used on enamel surfaces have on the bond strength of a composite resin to the dental enamel. Method and Materials: Eighty-eight bovine enamel fragments were mounted in acrylic resin bases. The enamel surfaces were sanded using 200-, 400-, and 600-grit sandpapers, thus creating a smear layer. These surfaces were then randomly divided in 2 groups: 1 of them received salivary contact for 10 minutes, and the other received it for 60 minutes. Then all surfaces were cleaned with a pumice and water paste applied with a rubber cup, followed by the application of biological detergent, sodium bicarbonate jet, or air/water spray. After cleansing, the enamel surfaces received the application of the Scotchbond Multi-Purpose adhesive system and Z100 composite resin, following the manufacturer's instructions, using an appropriate matrix. After storage at 37°C for 8 days, traction tests were carried out using an Instron machine operating at 0.5 mm/minute. Some fractured specimens (randomly chosen) were analyzed under scanning electron microscopy. Results: The statistical analysis using descriptive and inferential methods did not show significant differences between the different periods of time of salivary contact. The technique of pumice and water paste cleaning followed by the application of biological detergent was significantly more efficient than the others. Scanning electron micrographs of the fragments after traction tests confirmed these results. Conclusion: The technique of pumice and water paste cleaning followed by the application of biological detergent was the treatment that allowed the best results in terms of resin bonding to bovine enamel covered with acquired pellicle, and the sodium bicarbonate jet technique presented the lowest bond strength values and seemed to disturb the acid conditioning of enamel surfaces. Keywords: dental bonding, dental cavity preparation, dental enamel bonding

Objectives: This study investigated the microleakage, etching ability, and dentin-restorative interface of 2 different single-step self-etching bonding agents with compomers as restoratives. Method and Materials: Fifteen extracted noncarious human premolars were used for each dental material system. The bonding agent Xeno III was used with their compomer Dyract AP (Dentsply) and Adper Prompt L-Pop with their compomer Z2000 (3M Espe). Cylindrical cavities were prepared in enamel and dentin on the buccal surface at the cementoenamel junction and restored. The specimens were thermocycled and cut into slices, and the depth of dye penetration scored. The dentine-restorative interface was examined through a confocal scanning laser microscope. Results: Microleakages between the enamel and dentin sides differed significantly for Xeno (Wilcoxon rank sum test; P = .0058) as well as for Prompt (P = .0106), while the microleakages between the dentin sides of Xeno and Prompt did not differ significantly. However, between the enamel sides, a significant difference was found (P = .000), with the highest value for Prompt. The confocal laser studies showed tag formation, penetration of the bonding agents deep into the tubules, and hybrid layer formation for both bonding agents. Conclusions: It can be concluded that both adhesives gave microleakage values for dentin that are on the lower side. However, careful inspection of the enamel side indicated that both cannot be recommended for enamel sealing. Keywords: CLSM studies, microleakage, single-step self-etching bonding agents

Antibacterial activity of 4 commercial bleaching agents (Day White, Colgate Platinum, Whiteness 10% and 16%) on 6 oral pathogens (Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguinis, Candida albicans, Lactobacillus casei, and Lactobacillus acidophilus) and Staphylococcus aureus were evaluated. A chlorhexidine solution was used as a positive control, while distilled water was the negative control. Bleaching agents and control materials were inserted in sterilized stainless-steel cylinders that were positioned under inoculated agar plate (n = 4). After incubation according to the appropriate period of time for each microorganism, the inhibition zones were measured. Data were analyzed by 2-way analysis of variance and Tukey test (a = 0.05). All bleaching agents and the chlorhexidine solution produced antibacterial inhibition zones. Antimicrobial activity was dependent on peroxide-based bleaching agents. For most microorganisms evaluated, bleaching agents produced inhibition zones similar to or larger than that observed for chlorhexidine. C albicans, L casei, and L acidophilus were the most resistant microorganisms. Keywords: antimicrobial activity. bleaching agent, carbamide peroxide, oral microorganism

Objectives: To evaluate the tissue reaction of some pulpar protecting materials. Method and Materials: Standardized implants of calcium hydroxide (CH), glass-ionomer cement (GIC), and light-cured dentin adhesive (LDA), surgically introduced into the dorsal connective tissue of Wistar rats, were left for 15 and 30 days. For each of the 2 experimental times, a respective sham group (S) was studied. After experimentation, animals were sacrificed, and the material from implant sites was removed and studied with light microscopy and stereology (volume density of interstitial fibrosis, Vv[f], and numerical density of mast cells per area, NA[mast cell]). The implants and the surfaces of the fibrous capsule were analyzed with scanning electronic microscopy (SEM) adapted with microanalysis. Results: The CH group had the smallest value of Vv[f] and the LDA group the greatest. At day 30, the Vv[f] of the LDA group showed an increase of 30% and was different from that of the CH group in the same period (P .05). The NA[mast cell] was smaller in both the CH and the S group than in the LDA group (P .05). The GIC group had intermediate values for Vv[f] and NA[mast cell] between CH and LDA values. There was light fibrosis in the surgical area with few mast cells associated to vessels in the S group. SEM detected presence of silica fragments in the fibrous capsule of the LDA group and calcium in the fibrous capsule of the CH group. Conclusions: All tested materials allowed healing of the implanted area; tissue reaction was smallest in the CH group. Keywords: biocompatibility, calcium hydroxide, dentin adhesive, fibrosis, glass-ionomer cement, mast cell, stereology

A case of giant cell lesion as an initial feature of primary hyperparathyroidism is presented. A 55-year-old woman reported with a complaint of swelling and occasional pain in the upper-left posterior region with 2 months' duration. The diagnosis of a giant cell lesion with primary hyperparathyroidism was confirmed on the basis of radiological, biochemical, and histopathological investigative procedures. Keywords: brown tumor, giant cell lesion, ground-glass appearance, hyperparathyroidism, osteitis fibrosa generalisata, osteoporosis

Objectives: The purpose of this study was to evaluate compressive and tensile stress values and patterns on implant-supported all-ceramic restorations applied in maxillary partially edentulous cases by utilizing the 3-dimensional (3-D) finite element stress analysis. Method and Materials: Two different 3-D finite element designs representing a maxillary implant-supported fixed partial denture (from maxillary canine to second premolar) were constructed with 3 different core materials (Inceram-Zirconia, IPS 2 disilicate glass-ceramic, cobalt-chromium). In the first design, the cross-sectional connector areas of the dentures were constructed to be 3.5 3 3.5 mm. In the second design, the cross-sectional areas were decreased to 2 3 2 mm. A load of 550 N was applied in oblique direction onto the pontic. Results: The compressive and tensile stress levels obtained in the second design were higher than the first one for all materials. The compressive and tensile stresses were higher when the loads were directly applied onto the cores and the framework than when they were applied onto the porcelain sets. The cross-sectional connector area between the abutment and the pontic component has a great effect on the success of all-ceramic implant-supported fixed partial dentures. Conclusions: All 3 materials seem to have sufficient characteristic strength for 3-unit posterior implant-supported fixed partial dentures. Only the tensile stress value obtained for IPS 2 disilicate glass core material in the second design was higher than the material's characteristic strength value when the load was applied directly onto the core. Keywords: all-ceramic restorations, core materials, finite element stress analysis, fixed partial dentures, implant, stress concentration