Quintessence International, 08/2006

Objectives: The aim of this study was to determine the prevalence of the "golden proportion" in individuals presenting agreeable smiles. Method and Materials: Two hundred sixty university students aged 18 to 30 years of age (130 subjects of each gender) with maxillary incisors, canines, and premolars presenting anatomic integrity were evaluated. Agreeable smiles were considered to be those displaying at least second premolars; revealing no gingival recession in the smile area; having interdental papillae that filled all interdental spaces and were not hyperplastic; showing less than 3 mm of the maxillary gingiva; displaying the line of the lower lip parallel to the incisal line of the maxillary teeth and also to an imaginary line linking the contact points of these teeth; and, finally, presenting symmetry upon examination. Twenty-one individuals of this sample who presented this kind of smile (11 female and 10 male subjects) had their maxillary incisors, canines, and premolars of the same hemiarch measured in the cervicoincisal and mesiodistal directions using a periodontal probe, a digital Boley gauge, and digitalized analysis. Data were submitted to statistical analysis for comparison of adjacent teeth considering 1.618 (golden proportion) as a reference, with a statistical significance of P < .05. Results: Of the agreeable smiles evaluated, 7.1% exhibited the golden proportion. Conclusion: The golden proportion was not often found in adjacent teeth shown in smiles in the sample studied. Schlagwörter: clinical crown, epidemiology, esthetics, golden proportion, smile, tooth display

Objective: The purpose of this study was to discuss the concept of delaying the use of chlorhexidine mouthrinse (CHX) until some time after the use of dentifrice. Method and Materials: Sources included 13 electronic databases, 7 international drug reference books, and the World Wide Web; references of all relevant papers; and further information requested from authors and organizations. Inclusion criteria were a predefined hierarchy of evidence. Study validity was assessed with checklists. Two reviewers independently screened sources, extracted data, and assessed validity. Results: CHX, a cation, interacts and forms salts of low solubility and antibacterial activity with anions, such as sodium lauryl sulfate (SLS) and sodium monofluorophosphate (MFP). CHX and MFP are not compatible in clinically relevant concentrations in vitro. A 30-minute interval between SLS and CHX rinsing gave a significantly reduced antiplaque effect of CHX, whereas after 2 hours the neutralizing effect of SLS disappeared. Rinsing with dentifrice slurry and CHX produced a significantly increased plaque score compared to CHX and water. In regard to tooth staining by CHX mouthrinses, use of dentifrice before CHX showed a reduction in staining of 18%, whereas CHX followed by dentifrice showed a reduction in staining of about 79%. Literature relating to this interaction is limited; more controlled microbiologic and clinical studies are needed to certify the inaccuracy of this modality of administration. Conclusion: To optimize the antiplaque effect of CHX, it seems best that the interval between toothbrushing and rinsing with CHX be more than 30 minutes, cautiously close to 2 hours after brushing. Schlagwörter: chlorhexidine administration, dentifrice, sodium lauryl sulfate, sodium monofluorophosphate

Objective: The purpose of this preliminary investigation was to examine the presence of noncarious cervical lesions (NCCLs) among a convenience sample of non-toothbrushing subjects with Hansen's disease (leprosy). Method and Materials: A cross-sectional sample of 102 non-toothbrushing subjects (20 to 77 years of age) was examined. The clinical parameter of interest for this study was the presence or absence of NCCLs and their probable etiology as it relates to the subjects' diet, occlusion, and use of medication. Subjects were examined clinically and interviewed according to study protocol. Results: NCCLs were found in 48 subjects (47% of the studied sample). Widespread consumption of acidic foods and beverages acting as corrodents, signs of parafunction, and use of medication that causes xerostomia were also noted. Thus, all may be contributing factors in the etiology of NCCLs in this population. Conclusion: This preliminary report suggests that toothbrush/dentifrice abrasion was not a factor in the etiology of NCCLs in the population studied. The authors intend to expand their study among these non-toothbrushing subjects. Schlagwörter: abfraction, corrodent, corrosion, friction, mechanisms, noncarious cervical lesion, schema, stress

Objectives: The purpose of this study was to evaluate the effect of instrument lubricant on the cohesive strength of resin composite layers. Method and Materials: Clear acrylic molds were filled with 3 increments of a hybrid resin composite using a metal instrument. The first increment (shade A2) was inserted to a height of 4 mm and light cured, followed by a 1-mm-high second increment (shade A1). The composite instrument was then wiped with 1 of 7 lubricants before insertion of a 1-mm-high third increment (shade A1): (1) isopropyl alcohol gauze, 70% v/v (AL); (2) acetone (AC); (3) Adper Single Bond Adhesive (SB); (4) One-Step Adhesive (OS); (5) D/E Bonding Resin (DE); (6) Scotchbond Multi-Purpose Adhesive (SP); (7) Tescera Sculpting Resin (TE). No lubricant was used in the control group (CT). A final 4-mm-high increment (shade A2) was inserted and light cured. The blocks were sectioned to obtain 48 sticks for each group. Sticks were fractured with an Instron machine. Statistics were computed using 1-way analysis of variance and Duncan's test. Results: Outcomes were as follows (mean ± SD, MPa; same letters indicate significant differences at a confidence level of 95%): TE = 96.7A ± 17.8; SP = 93.6AB ± 9.6; DE = 93.4AB ± 16.2; OS = 91.9AB ± 19.5; AC = 90.1ABC ± 12.2; SB = 89.9ABC ± 14.5; AL = 88.8BC ± 16.8; CT = 84.7C ± 8.3. Conclusions: Although the difference between Tescera Sculpting Resin and alcohol was statistically significant, Tescera Sculpting Resin is recommended only for indirect composite restorations. The lubricant used to reduce stickiness between the resin composite used for direct restorations and the composite instrument did not significantly reduce bond strengths. Schlagwörter: bond testing, dental bonding, resin composite

Definite location of the surgical guide is critical to success in prosthetically driven implant dentistry. In edentulous mandibles, precise location of the surgical guide is difficult because of limited nonmobile surfaces. When surgical flaps are raised, this further reduces surfaces for locating the surgical guide. A technique is described in which 3 transitional implants are used to precisely locate the surgical guide then aid in relating the provisional restoration for immediate loading of the implants. Advantages of the technique are described and compared to other methods of locating the surgical guide. Schlagwörter: immediate loading, locating, surgical guide, transitional implants

Objective: This study tested the hypothesis that exposure of human molar teeth to tetracycline (TCN) derivatives in vitro results in tooth discoloration resembling the clinical presentation of TCN staining. Method and Materials: The effects of exposure of 20 extracted human molar teeth to distilled water, chlortetracycline, doxycycline, or minocycline were compared. The baseline color of each tooth was analyzed with a dental spectrophotometer. The pulp chambers were each filled with a TCN derivative solution and then sealed. The teeth were placed in a centrifuge tube and then centrifuged at 2,800 rpm for 20 minutes. Color change was monitored weekly for 7 weeks. Digital images of the surfaces were recorded. For each specimen at every evaluation period, color change from baseline was calculated using Commission Internationale d'Eclairage (CIE) Delta E 2000 (∆e00). Results: There was a significant association between the type of derivative used and ∆e00, as well as between the evaluation period and ∆e00. There was also a significant association between the interaction term, derivative 3 evaluation period, and ∆e00. Results of the Holm-Sidak post hoc test demonstrated that all 3 TCN derivatives were associated with significantly larger ∆e00 than the control group (P ¡Ü .05). Conclusions: All 3 TCN derivative solutions produced significant color changes as time progressed. Different TCN derivatives produced a different L* (lightness), C* (chroma), and H* (hue), with minocycline behaving distinctly differently from chlortetracycline and doxycycline. The model could be used to study the underlying mechanisms of TCN staining as well as many aspects of vital tooth bleaching. Schlagwörter: chlortetracycline, doxycycline, minocycline, tetracycline staining, tooth bleaching

Objective: The capability of drinks and foods to resist pH changes brought about by salivary buffering may play an important role in the dental erosion process in children. The aim of the present study was to test fruit yogurt, a popular snack for children, and the degrees of saturation (pK-pl) with respect to hydroxyapatite and fluorapatite to determine their erosive potential. Method and Materials: A variety of fruit yogurt was tested. To test the pH, 8 readings were taken with a pH electrode for each yogurt. Calcium content was detected by atomic absorption spectrophotometer, phosphorus by the inductively coupled plasma method, and fluoride content by ion chromatography. The degrees of saturation of hydroxyapatite and fluorapatite were calculated by use of a computer program. Statistical analysis was performed using 2-tailed analysis of variance (P < .05) and a post hoc test (Tukey) to determine differences between groups. Results: The pH of each fruit concentrate was significantly different, except for banana yogurt. Except for the phosphorus content of raspberry yogurt, the calcium and phosphorus content for each fruit concentrate were significantly different. Fluoride levels were the same for all yogurts tested, and the degrees of saturation of hydroxyapatite and fluorapatite was positive, indicating supersaturation. Conclusion: It could be stated that fruit yogurt has no erosive potential. Schlagwörter: dental erosion, fluorapatite, fruit yogurt, hydroxyapatite

Objective: Salivary incubation assays are commonly used in oral malodor studies. Using an in vitro model system, the effect of various natural medicinals (ie, echinacea, propolis, elder, mastic gum, marigold, sage, lavender, thyme, and chamomile) on salivary protein putrefaction and malodor production was examined. Method and Materials: Malodor production levels were scored by an experienced odor judge. Volatile sulfide levels were measured using a sulfide monitor (Halimeter), and salivary protein degradation was determined densitometrically following electrophoresis on polyacrylamide gel (SDS-PAGE). Microbial population was evaluated by viable counts and microscopy. Results: Whereas all of the various medicinals caused some reduction in malodor production from the incubated whole saliva, echinacea and lavender were the most effective. Conclusion: The bioassay utilized in the present study suggests that these herbs may inhibit oral malodor production. Schlagwörter: natural medicinals, oral bacteria, oral malodor, saliva

Suction cups, which provide high retention, are not being recommended anymore because of the destructive effect of the negative pressure on the palatal tissues. It is known that dentures with suction cups can cause perforations in the palate. In this case report, an oronasal communication caused by a denture with suction cup in a patient who had previously undergone pleomorphic adenoma excision of the palate is presented. Disadvantages of suction cups are emphasized. Schlagwörter: denture retention, oronasal communication, pleomorphic adenoma, suction cup