Quintessence International, 03/2008

Two cases of bisphosphonate-related osteonecrosis of the jaws are reported-one in the maxilla and the other in the mandible. The patients were treated with long-term antibiotics and minimal surgical debridement without major ablative surgery. Some clinical recommendations on prevention and management are suggested, as summarized from current literature. Keywords: bisphosphonate-related osteonecrosis of the jaws, management, prevention

Objectives: It has been suggested that tooth whitening might cause considerable pain. The aim of this study was to evaluate subjective intensities of pain during bleaching of vital teeth and to assess the patients' contentment with the treatment outcome. Method and Materials: Thirty patients were treated for 1 week in a double-blind study design. Employing gels containing 17%, 10%, or 0% (control group) carbamide peroxide, patients wore bleaching trays for 2 hours per day and described subjective intensities of pain while wearing the trays by means of a visual analog scale. The patients' subjective contentment with the bleaching outcome was measured with an intermodal intensity comparison. Results: For the 17% gel, a median value of 3.5 U (max: 10; min: 1) for pain intensity was observed; this was statistically different from the value seen with the 10% group (2.0 U; max: 7; min: 0) (P .05). Both test groups differed significantly from the control group, which had a median value of 0.0 U (max: 3; min: 0) (P .05). Patients' contentment with the treatment outcome did not differ between the test groups (P > .05), although statistical differences were observed between the control and the test groups (P .05) after bleaching for 1 week. Conclusion: Application of carbamide peroxide-containing bleaching agents to vital teeth causes pain correlated with the agent's concentration. Since both highly and less concentrated gels might result in a similar contentment with the treatment outcome, the use of highly concentrated agents appears not to be justified to improve vital tooth color. Keywords: carbamide peroxide, concentration of bleaching materials, contentment, customized bleaching tray, pain, patient satisfaction, vital tooth bleaching

Implant therapy in partially edentulous patients has proven to be a predictable procedure with a high implant survival rate. The success rate in patients with a history of aggressive periodontitis, however, is still unclear. A Medline/PubMed search was conducted to identify and summarize articles published in English and reported on the survival of implants in aggressive, rapidly progressive, or juvenile periodontitis patients. Our search revealed only 9 articles, 4 of which were case reports. Although available evidence is weak, it suggests good short-term survival of implants placed in periodontally well-maintained aggressive periodontitis patients. Bone loss around implants in aggressive periodontitis patients, however, appears to occur more frequently than it does in chronic periodontitis patients or periodontally healthy individuals. A summary and critical analysis of the aforementioned articles is presented. Keywords: aggressive periodontitis, dental implants, juvenile periodontitis, periodontally compromised patients, rapidly progressive periodontitis

Objectives: Polymorphisms for toll-like receptor (TLR) 2 gene (Arg677Trp, Arg753Gln) and TLR4 gene (Asp299Gly, Thr399Ile) that are associated with impaired lipopolysaccharide (LPS) signal transduction have recently been described. The present study aimed to investigate the relationship between TLRs 2 and 4 gene polymorphisms and periodontitis in a Chinese population. Method and Materials: Forty patients with generalized aggressive periodontitis, 50 patients with chronic periodontitis, and 100 periodontally healthy controls were recruited. All these subjects were of Han Chinese ethnicity. Genomic DNA was extracted from whole-blood samples. TLRs 2 and 4 genes were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with respective restriction endonucleases. The alleles were detected by polyacrylamide gel electrophoresis and visualized with ethidium bromide. Results: Heterozygosity for the TLR2 Arg677Trp polymorphism was found in all subjects. The TLR2 Arg753Gln mutant allele was not found in periodontitis patients, while a heterozygous frequency of 6% (6 of 100) was detected in the controls. The TLR4 Asp299Gly and Thr399Ile mutant alleles were not found in any of the subjects. Conclusion: TLR2 Arg753Gln polymorphism may not be associated with aggressive or chronic periodontitis in the Chinese population. The prevalence of TLR2 Arp677Trp polymorphism seemed to be rather high, while that of TLR4 Asp299Gly and Thr399Ile polymorphisms seemed to be rather low in the Chinese population, which did not permit any conclusion regarding its effects on periodontitis. Keywords: Chinese, periodontitis, polymorphism, susceptibility, toll-like receptors

Sinus tracts are a consequence of chronic apical disease or vertical root fractures. They are usually diagnosed upon routine clinical examination or in response to patient complaints of swelling and occasional pus secretion. An unusual case report of a maxillary canine with multiple orifices of sinus tracts is presented. Vertical root fracture was confirmed after removal of the root canal filling under an operating microscope. Clinicians should suspect vertical root fracture when multiple sinus tracts originating from the same tooth are observed. Keywords: multiple, sinus tract, tracing, vertical root fracture

Objectives: To determine the disinfecting effect of ozonized oxygen (120 seconds from the HealOzone generator, KaVo) on Enterococcus faecalis, representing bacteria that are difficult to eliminate in the root canals of human teeth, and to compare it with the conventional irrigants: sterile physiologic sodium chloride solution (negative control group), 3% hydrogen peroxide solution, 0.2% chlorhexidine solution, 1.5% sodium hypochlorite solution, and 3% sodium hypochlorite solution (positive control group). Method and Materials: The roots (n = 10 in each group) were sterilized, contaminated with the test microorganisms in a quantitative preparation, rinsed with the test solutions, and dried. The residual concentration of E faecalis was determined through another irrigation stage with the sodium chloride solution. Results: The positive control group showed a significantly lower concentration of microorganisms than all the other groups, whereas the negative control group showed a significantly higher concentration compared to the other groups. The test groups showed low concentrations. Conclusion: Ozonized oxygen appears to be suitable for disinfecting root canal systems in cases where sodium hypochlorite is not indicated. Keywords: chlorhexidine, ozone, root canal cleaning, sodium hypochlorite

Objective: To compare the relative penetration of Prevotella melaninogenica and Enterococcus faecalis through 3 guided tissue regeneration membranes: Atrisorb, Lambone, and OsseoQuest. It was hypothesized that OsseoQuest would show increased bacterial penetration when compared to Lambone and Atrisorb. Method and Materials: Centrifuge tubes containing trypticase soy broth were sealed with circular sections of membranes and placed in test tubes containing culture media. The bacterial penetration was assessed by passage of bacteria from the outer tube culture media to the inner centrifuge tube media through the membrane. After incubation for 4 and 48 hours, the media from the outer and inner tubes were compared for bacterial count. Results: P melaninogenica exhibited 91% penetration for Lambone in 2 days, while OsseoQuest displayed 87% penetration with E faecalis in the same time. Atrisorb displayed a minimal penetration with both bacteria (2%). Conclusion: Atrisorb displayed the least bacterial penetration, which may be attributed to membrane structure, chemical configuration, hydrophobicity, and porosity of tested membranes. Keywords: bacterial penetration, barrier membranes, Enterococcus faecalis, guided tissue regeneration membrane, Prevotella melaninogenica, surgery

Objective: Modulated curing methods could lead to a higher probability of bond preservation. Therefore, the aim of this study was to evaluate the effect of 7 curing methods on bond strength of composite resin restorations. Method and Materials: Seventy bovine incisors were selected. A conical cavity was prepared in the buccal surface. Adper Single Bond adhesive system was applied according to the manufacturer's instructions, and the cavities were filled with a single increment of Esthet X (Dentsply/Caulk). The specimens were randomly assigned into 7 groups (n = 10) according to the photoactivation method: (1) continuous light 700 (700 mW/cm2) (control); (2) continuous light 150 (150 mW/cm2); (3) continuous light 250 (250 mW/cm2); (4) soft-start 75 (75 mW/cm2) + 700 mW/cm2); (5) soft-start 150 (150 mW/cm2 + 700 mW/cm2); (6) pulse-delay (150 mW/cm2 + 3 minutes + 700 mW/cm2); and (7) intermittent light (cycles at 600 mW/cm2). The energy density for all groups was 14 J/cm2. The bond strength of the composite restorations was measured by performing the push-out test in a universal testing machine (Instron). The results were submitted to ANOVA and Tukey test (P .05). Results: Pulse-delay, soft-start 150, and soft-start 75 methods showed a significant increase in bond strength when compared with the control continuous light 700 method. Low power density and intermittent light groups showed intermediate results. Conclusion: Modulation of the energy density during light curing of composite resins using pulse-delay or soft-start methods increased the bond strength of composite restorations. Keywords: bond strength, composite resin restorations, photoactivation methods, power density, pulse-delay, push-out test, soft-start polymerization

Ehlers-Danlos syndrome (EDS) is a hereditary disorder of the connective tissue related to collagen metabolism. Deficiency or alteration of the collagen present in the tissues results in some classic signs such as skin hyperelasticity, articular hypermobility, and vascular fragility, among others. In addition, EDS oral manifestations are rarely cited in the literature. The aim of this article is to report a rare case of a young female patient with EDS who presented supernumerary teeth and an odontogenic keratocyst. There is no report in the literature of the simultaneous occurrence of these alterations. The article further highlights the importance of EDS diagnosis in patients who need dental treatment and the due care for their assistance. Keywords: articular hypermobility, Ehlers-Danlos syndrome, odontogenic keratocyst, skin hyperelasticity, supernumerary teeth

Dentinogenesis imperfecta, also known as hereditary opalescent dentin, is a dentin development disorder with autosomal dominant transmission that affects both the primary and permanent dentition. A case is reported of a family in which the mother and her 6- and 20- year-old children were diagnosed with dentinogenesis imperfecta type II. The mouths of these patients illustrate the progressive deterioration of affected teeth if not adequately treated. The treatment of the 6-year-old son is described, and therapeutic approaches to this disorder in primary and permanent dentition are reviewed. This family exemplifies the need for the earliest possible diagnosis and treatment of dentinogenesis imperfecta to prevent extensive deterioration of the dentition and occlusion. Keywords: dentinogenesis imperfecta, complications, hereditary opalescent dentin, pathology, pediatric dentitry, tooth rehabilitation

Objective: To investigate the dimensional changes and the surface quality of dental impression materials after disinfection with 3 chemically different agents. Method and Materials: Four alginate impression materials and 1 addition silicone material were selected. The impressions were made from a brass model simulating a 3-unit fixed partial denture. The chemical disinfection was performed with 3 different disinfectants for 10 minutes. Three samples of each impression material and disinfectant agent were investigated. As a control, 3 impressions of each material were made without any disinfection. The casts were made with a type IV dental stone. For each cast, 6 diameters and 3 distances were measured. To evaluate the dimensional stability, measurements were taken at a magnification of 343 with a light microscope. The surface quality was recorded using a profilometer. Results: The dimensional change and surface quality differed minimally; however, statistically significant differences were found between alginate and addition silicone impression materials (ANOVA, P .05). Casts from the silicone impressions were more accurate than the casts from alginate impressions. Conclusion: Different impression disinfection methods have only a marginal influence on dimensional stability and surface quality of dental casts. To achieve a higher precision, the use of an addition silicone can be recommended. Keywords: addition silicone, alginate, dental impression materials, dimensional stability, disinfection, surface quality

Objective: The number and distribution of occlusal contacts in centric occlusion (CO) and centric relation have been studied by a number of authors. All these studies have one thing in common-they define the greatest number of occlusal contacts between the molars. The purpose of the present study was to register the maximum clenching forces in CO, as well as to analyze the anatomic and functional factors that determine their localization on teeth. Method and Materials: The study included 42 subjects, aged 19 to 26 years, with intact dentition and Class I Angle occlusion; 38 persons had 1 to 4 restorations on the premolars and molars. The occlusal contacts were investigated in CO by the T-Scan system (Sentek) on wax and silicone impressions. The force loads in different sections of the dentition were differentiated by an additionally developed computer program. Results: The T-Scan analysis and the developed computer program revealed that the maximum values of the clenching forces were recorded on the third molars. The strongest contacts found by the T-Scan system were successfully visualized in wax and silicone impressions. Conclusion: The maximum clenching forces of the masticatory muscles recorded by the T-Scan system were located in CO at the third molars in a dentition of 32 teeth and at the second molars in a dentition of 28 teeth. If the above-mentioned phenomenon is not taken into consideration in clinical practice, occlusal contacts may be created that will unfavorably transfer the specific clenching forces to a more medially located molar in cases of occlusal restoration of the same molar by a restoration or a single crown. Keywords: centric occlusion, occlusal contacts, T-Scan

Objective: To evaluate the water-sorption characteristics and the solubility behavior of 4 luting cements-2 composite resins (CRs), a polyacid-modified composite resin (PMCR), and a resin-modified glass-ionomer cement (RMGIC)-according to the ISO 4049 specifications. Method and Materials: Five disks (15 3 1 mm) of each material (Variolink II [CR1; Vivadent], Panavia F [CR2; Kuraray], Resinomer [PMCR; Bisco], and Fuji Plus [RMGIC; GC]) were prepared according to the manufacturers' instructions. Specimens were first desiccated until a consistent mass was obtained. Specimens were immersed for 7 days in distilled water and immediately weighed after this period. Then the disks were post-desiccated and weighed every day for 35 days. The water sorption and solubility of each specimen were calculated according to the change in its weight as observed before and after immersion and desiccation periods. Results: Fuji Plus exhibited the overall higher values of water sorption and solubility (P .001). Of the 3 resin-based luting cements, Resinomer demonstrated significantly higher water sorption and solubility (P .001), whereas Variolink II and Panavia F showed low values and were not significantly different (P = .2). Conclusions: Behavior of resin-based materials in water varies according to the composition characteristics. In particular, the high portion of hydrophilic chemical species, as well as the filler characteristics, provoke very high water sorption and solubility values. In this way, and within the limitations of this in vitro study, composite resin luting cements appear to be more suitable than compomers and resin-modified glass-ionomer cements to meet longevity requirements. Keywords: dental polymers, ISO 4049 specifications, luting cements, solubility, water sorption

Objective: To determine dental agenesis prevalence in Sayada, Tunisia, a town from where many patients attend the Pediatric Department of Monastir University Dental School for such abnormalities, and to analyze its mode of inheritance. Method and Materials: A total of 262 schoolchildren in permanent dentition (134 females and 128 males) aged 12 to 18 years (mean, 14.1 ± 1.2 years) were examined to detect dental agenesis. In the case of a missing permanent tooth, a panoramic radiograph was taken to confirm diagnosis. A family survey questionnaire was completed for each case of multiple agenesis (at least 4 teeth missing). Results: Findings revealed a dental agenesis prevalence of 13.3%. Altogether, 62 teeth were missing. No case of syndromal agenesis was detected; however, 12 children presented multiple agenesis (34.3%). The family survey was completed for only 9 of these subjects. Conclusion: Literature review showed a lower dental agenesis prevalence (3% to 7%) than did the present study. In the present study, females were more affected by this abnormality than males (16.4% and 10.3%, respectively). With the exception of third molars, the tooth most often missing was the mandibular second premolar (30.6%), followed by the maxillary second premolar (17.7%); hypodontia seemed to be symmetrical. Family surveys revealed a high rate of consanguinity in Sayada. Pedigree analysis of 9 families showed that dental agenesis was probably related to an autosomal dominant inheritance. Keywords: dental agenesis, epidemiology, mode of transmission, pediatric dentistry, pedigree, Tunisia

Objective: Resonance frequency analysis (RFA) has enabled the assessment of implant stability in terms of implant stability quotient (ISQ) units. This study evaluated the long-term stability of endosseous implants according to an ISQ scale of 1 to 100, as estimated by RFA in the posterior partially edentulous mandible. Method and Materials: A 2-stage procedure was used to place 328 Bränemark implants in the edentulous mandibular molar region (second premolar to second molar) of 113 patients (49 men and 64 women). Patients were followed at regular intervals postoperatively, and ISQ scores were evaluated by RFA every year for 10 years. Results: The implant success rate was 100%. ISQ scores did not significantly differ in the pattern of stability changes among different bone quantities and qualities during long-term follow-up. There was no significant difference in implant stability among the mandibular sides, the sites, and the sexes. Conclusion: Long-term stability of Bränemark implants was excellent in the posterior partially edentulous mandible. Keywords: dental implant, long-term clinical study, posterior partially edentulous mandible, resonance frequency, stability

Objectives: To find the geometric values of emergence angles in human natural anterior teeth and to study their influence on periodontal status. Method and Materials: Fifty anterior teeth with full-crown restorations and homologous contralateral sound teeth were examined for clinical parameters: Plaque Index, Gingival Index, probing depth, and clinical attachment loss. Impressions and stone casts were made and then separated along the midline of the teeth. All cut-surface specimens were photocopied, scanned, and transferred into graphic form with a special program. The emergence angles of both restored and natural teeth were processed and recorded. Paired t test and multivariate linear regression analysis were used for statistical analysis. Results: Mean supragingival emergence angles for facial and lingual surfaces of natural anterior teeth were 11.13 ± 7.92 and 15.58 ± 9.16 degrees, respectively. The corresponding values for subgingival emergence angles were 9.93 ± 5.68 and 14.35 ± 8.44 degrees. The periodontal parameters were higher in restored teeth than in natural teeth. When Plaque Index and gender were controlled, a correlation was shown between the lingual subgingival emergence angle of the restored teeth and probing depth. A correlation was also found between the lingual supra- and subgingival emergence angles, as well as between both angles of the restored teeth and the attachment loss. Conclusion: The mean values of emergence angles obtained may aid clinicians and dental technicians in more easily designing the definitive emergence profile of restorations. The emergence profile of the restored teeth may affect periodontal status on the lingual aspect. Keywords: clinical attachment loss, emergence angle, emergence profile, periodontal status, subgingival emergence angle, supragingival emergence angle

Objective: To evaluate retentive strength and film thickness of complete metal crowns cemented to overtapered teeth with 3 different cements after the application of airborne-particle abrasion. Method and Materials: Sixty extracted maxillary molar teeth were embedded in autopolymerizing resin. Crowns were prepared with 30-degree overtapered axial walls and a 1-mm shoulder margin using a water-cooled cylindrical airborne-particle abrasion device. Then, 60 complete crowns were made from a nickel-chromium alloy. Teeth and crowns were assigned to 2 groups, 30 to the control group and 30 to the experimental group to undergo airborne-particle abrasion. In the first part of study, 30 teeth from the experimental group were submitted to the silicon-replica technique and their buccolingual cross sections were measured so that cement film thickness could be measured before airborne-particle abrasion. Three measurements using a light microscope were made in 7 regions of each tooth. In the second part of study, complete metal crowns with and without airborne-particle abrasion were distributed into 3 groups with 10 teeth each to be cemented with zinc phosphate, polycarboxylate, or resin-modified glass ionomer. All specimens were subjected to a tensile bond test in an universal testing machine at a crosshead speed of 0.1 mm/min until failure. The results were then evaluated with Student t test at a 5% level of significance. Results: The film thickness showed no statistically significant differences among groups (P > .05). There was a significant difference between the control and experimental groups, with an increase in all 3 cements after airborne-particle abrasion (P .05). The highest retentive strength in the control group was found with resin-modified glass ionomer (141.4 ± 56.7 N), but there was no significant difference between the resin-modified glass ionomer (141.4 ± 56.7 N) and zinc phosphate (121.4 ± 24.2 N) (P > .05). Retentive strength of polycarboxylate was the lowest (78.03 ± 16 N) (P .05). For the experimental group, the difference among the zinc phosphate (220.5 ± 83.8 N), polycarboxylate (185.4 ± 60.8 N), and resin-modified glass ionomer (228.9 ± 62.4 N) was not statistically significant (P > .05). Conclusion: Airborne-particle abrasion had a positive effect on the retention of complete metal crowns when the crowns were cemented with zinc phosphate cement, polycarboxylate cement, or resin-modified glass-ionomer cement. Keywords: airborne-particle abrasion, film thickness, overtapered restoration, resin-modified glass-ionomer cement, retentive strength, zinc phosphate cement