Quintessence International, 10/2009

The management techniques reported for dental fusion are usually complex, invasive, and irreversible. This case report describes a novel, simple technique to manage double teeth using resin restorations. The promising results obtained will encourage dental practitioners to consider this conservative approach before more complex treatment alternatives. Keywords: composite resins, conservative management, fused teeth, incisor abnormalities, permantent dental restoration

Oral non-Hodgkin lymphomas are uncommon, and those arising on the gingiva are rare. A case of non-Hodgkin lymphoma of the gingiva that was erroneously diagnosed and treated as a dental abscess is presented. Clinical examination showed a firm and ulcerated mass extending from the mandibular right first premolar region to the retromolar trigone. Resorption of the alveolar ridge was radiographically observed. Histologic analysis revealed a large B-cell non-Hodgkin lymphoma. No other evidence of the disease was found except in the mandible. The patient was treated with chemotherapy that resulted in complete regression. As primary non-Hodgkin lymphoma of the gingiva can be misdiagnosed as a trivial inflammatory lesion, a histologic examination should be mandatory in those cases in which symptoms do not subside after specific treatment. Keywords: differential diagnosis, gingiva, immunohistochemistry, non-Hodgkin lymphomas, oral cavity

Extensive exposure of the gingiva during a smile, called excessive gingival display, may be a point of concern for both patients and clinicians. Patients often present to the dental clinic seeking a solution to their "gummy" appearance. A clinician must fully understand the various factors involved in this situation, to provide patients with an appropriate answer. Thorough examination followed by the right diagnosis is imperative for achieving an esthetic and predictable result in the treatment of such situations. The aim of this article is to discuss the various aspects of excessive gingival display and its etiology and to present the current solutions that exist in the literature. Keywords: altered passive eruption, diagnosis, etiology, excessive gingival display, gummy smile, vertical maxillary excess (VME)

Objective: To examine the relationship between periodontal diagnosis and prognosis and survival of prosthodontic abutments over time. Method and Materials: The study consisted of 70 randomly selected patients with either fixed or removable partial dentures delivered by dental students. Age, gender, ethnicity, pertinent medical history, smoking status, procedure performed, abutment tooth number, year of prosthesis delivery, year of most recent periodontal examination, year of tooth loss, periodontal diagnosis and prognosis, date of prosthesis delivery, and most recent periodontal examination were extracted from dental charts. Statistical analyses included chi-square, Kaplan-Meier, and Cox proportional hazards models. Results: A total of 16 of 226 abutment teeth (7.1%) were lost. A total of 88.6% of subjects lost no abutment teeth during the study, while 15.7% lost at least 1 tooth. Analysis showed a cumulative 13.8-year survival rate of 66.0% (SE = ± 0.10). Toothspecific periodontal prognosis was a significant predictor of tooth loss. The data showed a 3.05-fold increased risk for tooth loss with removable partial denture abutments compared to fixed partial denture abutments. Abutment teeth with an initial specific prognosis of "good" had a 9.3-fold lower risk of loss than teeth with any other specific prognosis. Conclusions: Teeth with a periodontal prognosis other than good and those used as removable partial denture abutments had an increased risk of tooth loss. Periodontal diagnosis, overall prognosis (prognosis for the entire dentition), gender, ethnicity, smoking status, and diabetes were not significantly associated with abutment tooth loss over time. Keywords: failure rate, periodontal diagnosis, periodontal prognosis, prosthodontic abutments, risk factor, survival rate, tooth loss

Objective: To compare the interobserver difference in visual shade matching and estimate the precision of color discrimination. Method and Materials: Visual shade matching of a maxillary central incisor of 33 subjects was performed by 2 prosthodontists independently in a chair under ceiling daylight-corrected fluorescent lighting, using the Vitapan Classical and the Vitapan 3D Master shade guides (Vita Zahnfabrik). The 3 closest shade tabs were selected and ranked in order of best, second best, and third best matches. Interobserver agreement was found by comparing the best shade and the common shade for each subject by the 2 clinicians. The CIE Lab color difference, ΔE*, between the best shade and the common shade selected by the clinicians was calculated for each subject. A t test (α = .05) was performed to find clinician differences of the means of the best shade and the common shade for both shade guides. Results: Interobserver agreement was 30% when matching the best shade; however, the ratio increased to over 85% for the common shade (a significant difference at the .05 level). No significant differences were found between the 2 shade guides by means of the mean color differences between the best shade match and the common shade match, while the Vitapan 3D Master shade guide was superior to the Vitapan Classical shade guide in reducing the interobserver color differences from 0.8 to 0.2. Conclusion: Visual shade matching of teeth gave better agreement using the Vitapan 3D Master shade guide when selecting the common shade from among the closest 3 shades chosen by multiple observers. Keywords: best shade, CIE Lab color difference, common shade, interobserver agreement or disagreement, visual shade matching

To the authors' knowledge, this is the first reported case of an odontogenic carcinoma with documented skeletal muscle differentiation (rhabdomyosarcoma). The histology and clinical features of this aggressive odontogenic neoplasm are described. Within the English-language literature, only 2 cases are reported of an odontogenic tumor with muscle differentiation: a benign odontogenic tumor (ameloblastoma) with differentiation into a rhabdomyosarcoma and an odontogenic sarcoma with smooth-muscle differentiation. The general practitioner should be aware that odontogenic lesions may be malignant, even though this is extremely rare, and all tissue removed from the oral cavity should be submitted for biopsy. Keywords: neoplasm, odontogenic carcinoma, ondontogenic tumor, rhabdomyosarcoma

Objective: To determine whether temperature affects the polymerization shrinkage of composite resin. Method and Materials: Volumetric shrinkage of a microfill composite was measured using a video-imaging device. The material was cooled to 4°C or heated to 37°C, 54°C, or 68°C. Room-temperature (20°C) composite was used as the control. The composite was light activated using a quartz-tungsten-halogen curing device. Polymerization shrinkage was recorded at 1-minute intervals for 10 minutes after the beginning of photoinitiation. The data were subjected to ANOVA, Fisher's PLSD test, and linear regression analysis (α = 0.05). Results: Volumetric shrinkage ranged from 0.2% to 4.7%. Shrinkage of the composite at 37°C was similar to that at room temperature. Preheating the composite to 54°C or 68°C significantly increased shrinkage. The apparent polymerization shrinkage of the refrigerated composite was significantly less than that of the control, although this might have been an artifact of the test method. Regression analysis revealed a strong correlation between temperature and volumetric shrinkage. Conclusion: Preheating composite to relatively high temperatures (54°C or 68°C) to increase its flow and adaptation causes an increase in volumetric shrinkage. At body temperature, composite shrinkage is similar to that at room temperature. Keywords: composite resin, polymerization shrinkage, preheating

Objective: To conduct a systematic review to assess and analyze the scientific evidence about the available therapies for bruxism in children. Method and Materials: The literature was searched using Medline, PubMed, Ovid, Biomed Central, EBSCOhost, ISI, Cochrane Library, Embase, LILACS, Scielo, Scirus, the Internet at large, and databases of universities from March 1985 to the end of September 2007. Studies had to be intervention studies for bruxism in children, and the children included in the studies had to be 3 to 10 years old. Results: From 52 records found, 2 fulfilled the inclusion criteria. In 1 study, bruxism was treated by widening the upper airway through adenoidectomy, and the other study proposed to treat bruxism in children with psychologic techniques. When analyzed, the 2 considered studies did not fully accomplish the requirements to treat the etiology of bruxism in children. Conclusion: The available literature does not provide adequate support to treat bruxism in children, as the diagnosis methods in the studies are insufficient and are not comparable to confirm the presence of bruxism. Very few studies about therapies for bruxism in children meet the quality criteria required for the evidence-based practice. Treatment for bruxism in children requires further study. Keywords: adenoids, bruxism, children, pharmacology, psychology, physiotherapy, tonsil, treatment

Objectives: To report a novel observation of neutrophil signal transduction abnormalities in patients with localized aggressive periodontitis (LAP) that are associated with an enhanced phosphorylation of the nuclear signal transduction protein cyclic AMP response element-binding factor (CREB). Method and Materials: Peripheral venous blood neutrophils of 18 subjects, 9 patients with LAP and 9 race-, sex-, and age-matched healthy controls, were isolated and prepared using the Ficoll-Hypaque density-gradient technique. Neutrophils (5.4 x 106/mL) were stimulated with the chemoattractant FMLP (10-6 mol/L) for 5 minutes and lysed. Aliquots of these samples were separated by SDS-PAGE (60 µg/lane) on 9.0% (w/v) polyacrylamide slab gels and transferred electrophoretically to polyvinyl difluoride membranes. The cell lysates were immunoblotted with a 1:1,000 dilution of rabbit-phospho-CREB antibody that recognizes only the phosphorylated form of CREB at Ser133. The activated CREB was visualized with a luminol-enhanced chemoluminescence detection system and evaluated by laser densitometry. Results: In patients with LAP, the average activation of CREB displayed an overexpression for the unstimulated peripheral blood neutrophils of 80.3% (17.5-fold) compared to healthy controls (4.6%). Conclusion: LAP neutrophils who express their phenotype appear to be constitutively primed, as evidenced by activated CREB in resting cells compared to normal individuals. The genetically primed neutrophil phenotype may contribute to neutrophil-mediated tissue damage in the pathogenesis of LAP. Keywords: host defense mechanisms, localized aggressive periodontitis, nuclear transcription factor CREB, primed LAP neutrophil phenotype, signal transduction abnormalities

Objective: To evaluate tensile bond strengths of 2 dentin bonding agents containing solvents on Nd:YAG and Er,Cr:YSGG laser-etched dentin surface. Method and Materials: Occlusal enamel of 146 molars was removed, and exposed surfaces were ground with a diamond bur to produce bur-cut dentin surfaces. Of those teeth, 120 were assigned to 3 groups of 40 samples in which dentin was conditioned with Er,Cr:YSGG laser, Nd:YAG laser, and 37% orthophosphoric acid (control). Each group was further divided into 2 subgroups, acetone- and ethanol-containing bonding agents, and 4-mm-long x 4-mmwide composite rods were bonded to all specimens using a Plexiglas mold. Tensile bond strength testing of 120 samples was performed at a crosshead speed of 0.5 mm/min using a 50-kgf load cell. The remaining 26 samples were examined under SEM to evaluate the adaptation/penetration of the bonding materials and the alterations in mineral content. Data were analyzed using 1-way ANOVA and Kruskal-Wallis tests; P .05 was considered statistically significant. Results: The difference between the mean tensile bond strength values obtained with bonding agents was statistically significant in the control group. The bond strength values of the acetone-containing agent in this group were found to be higher than the ethanol-containing agent (P .001). When compared with Nd:YAG laser, bond strength values obtained with Er,Cr:YSGG laser were higher (P .001). The bond strength values obtained in the acid-etched group were highest for both bonding agents and demonstrated statistical significance (P .001). Conclusion: Although in this study laser etching is more influential than the solvent type on bond strengths of dentin bonding agents, it cannot be considered as an alternative to conventional acid etching. Keywords: acid etching, adhesives, dentin, Er, Cr:YSGG laser, Nd:YAG laser, tensile bond strength

Objective: To determine the effect of irrigation time on the removal of dentin debris from root canals irrigated with passive ultrasonic irrigation comparing 2 flushing methods. Method and Materials: Root canals with a standardized groove in 1 canal wall, which was filled with dentin debris, were irrigated ultrasonically or with syringe irrigation. The quantity of dentin debris after irrigation was determined. In groups 1 to 4, the irrigant was activated by an ultrasonically activated file. In groups 1 and 2 (n = 20), the canals were flushed 3 or 1.5 minutes using a continuous flow of irrigant. In groups 3 and 4 (n = 20), the irrigation time was 1 or 3 minutes, and the canals were flushed 3 times by syringe irrigation (intermittent flushing method). In group 5 (n = 20), the root canals were flushed 3 times using syringe irrigation. Results: Significantly more dentin debris was removed when the irrigant was activated by ultrasound (P = .000). Significantly less dentin debris was removed when the root canals were irrigated with a continuous flow of irrigant for 1.5 minutes (P = .005). Conclusions: Three minutes of ultrasonic irrigation with the intermittent flush technique or a continuous flow is as effective as 1 minute with the intermittent flush technique. The efficiency of the ultrasonic irrigation with a continuous flow is time dependent, 1.5 minutes being less efficient than 3 minutes. Keywords: continuous flow, flushing method, irrigant, irrigation, passive ultrasonic irrigation, root canal, time

Objective: Four common antimicrobial agents were evaluated for their efficacy in reduction of aerobic bacteria intraorally grown in biofilms on rough titanium samples. The solutions investigated contained chlorhexidine, essential oil, octenidine, or citric acid. Method and Materials: Twenty volunteers wore splints with titanium sleeves intraorally for 10 days. Following irrigation with the antiseptics, the sleeves were removed and biofilm samples were taken by swabbing. The bacteria were first examined microscopically by Gram staining. These samples from the surfaces were then cultured under aerobic conditions to identify and quantify the colonizing bacteria. Results: Compared to untreated controls, significant (P .05) differences in antimicrobial efficacy were observed for the different regimens depending on bacterial species or even the subtype. The reduction rates achieved varied from 30.0% after 2 minutes of rinsing with chlorhexidine to 99.8% after 8 minutes of rinsing with octenidine. Conclusion: The irrigation regimens studied in this investigation reduced bacterial colonization in a mature biofilm grown intraorally on rough titanium surfaces. The highest absolute reduction was achieved after 8 minutes, but only the 2-minute reduction rates are significant for clinical practice. Taking this into consideration, the distinct decontamination efficacy of octenidine and citric acid is evident.

This article reports a case of periapical cemental dysplasia affecting the mandibular incisors in 38-year-old twin sisters. The major concern is failure to recognize the nature of the lesion, which may result in unnecessary root canal treatment or extractions on the assumption that the lesion represents inflammatory periapical pathosis.

Objectives: To evaluate the effect of microwave postpolymerization heat treatment and water storage time on the cytotoxicity of denture base and reline acrylic resins. Method and Materials: Sample disks of 6 acrylic resins were fabricated under aseptic conditions (Kooliner, GC; Tokuyama Rebase II, Tokuyama Dental; New Truliner, Bosworth; Acron MC, GC; Lucitone 550, Dentsply; QC 20, Dentsply). The denture base acrylic resin samples were stored in water for 24 and 48 hours at 37°C. The fabricated samples were further subdivided into 2 groups: (1) samples without heat treatment and (2) samples treated in a microwave. The 3H-thymidine incorporation test was used to determine the cytotoxicity of the materials. The data were statistically analyzed using the incomplete 3-way ANOVA and Tukey HSD tests (P .05). Results: Microwave postpolymerization heat treatment improved the biocompatibility of Tokuyama Rebase II. Tokuyama Rebase II without heat treatment and Acron MC in both experimental groups were graded as slightly cytotoxic in the group without water storage. The other resins were graded as noncytotoxic. After 24 hours of immersion in water, all materials were graded as noncytotoxic. After water storage for 48 hours, Acron MC without heat treatment and QC 20 in both experimental groups were graded as slightly cytotoxic. Lucitone 550 was graded as noncytotoxic in all experimental groups. Conclusion: Microwave irradiation may be considered an alternative to reduce the cytotoxicity of Tokuyama Rebase II. Dental practitioners should choose Lucitone 550 processed with terminal boiling stage. Keywords: biocompatibility, cell viability, microwave, polymethyl methacrylate