Quintessence International, 02/2009

Objective: To compare in vitro the remineralizing effects of different regular dentifrices and whitening dentifrices (containing pyrophosphates) on predemineralized enamel. Method and Materials: Specimens from 84 bovine incisors were embedded in epoxy resin, partly covered with nail varnish, and demineralized in a lactic acid solution (37°C, pH 5.0, 8 days). Parts of the demineralized areas were covered with nail varnish, and specimens were randomly assigned to 6 groups. Subsequently, specimens were exposed to a remineralizing solution (37°C, pH 7.0, 60 days) and brushed 3 times a day (1:3 slurry with remineralizing solution) with 1 of 3 regular dentifrices designed for anticaries (group 1, amine; group 2, sodium fluoride) or periodontal (group 3, amine/stannous fluoride) purposes or whitening dentifrice containing pyrophosphates (group 4, sodium fluoride). An experimental dentifrice (group 5, without pyrophosphates/fluorides) and a whitening dentifrice (group 6, monofluorophosphate) served as controls. Mineral loss and lesion depths were evaluated from contact microradiographs, and intergroup comparisons were performed using the closed-test procedure (alpha =.05). Results: Compared to baseline, specimens brushed with the dentifrices containing stannous/amine fluorides revealed significant mineral gains and lesion depth reductions (P .05). Concerning the reacquired mineral, the whitening dentifrice performed worse than the regular dentifrices (P > .05), while mineral gain, as well as lesion depth, reduction was negligible with the control groups. Conclusion: Dentifrices containing pyrophosphates perform worse than regular dentifrices but do not necessarily affect remineralization. Unless remineralizing efficacy is proven, whitening dentifrices should be recommended only after deliberate consideration in caries-prone patients. Keywords: artificial caries, dentifrices, enamel, fluoride, in vitro, remineralization, tooth whitening, transversal microradiography

Objective: To determine the effect of deproteinization on the success of composite crowns in hypocalcified amelogenesis imperfecta-affected permanent teeth in intraoral conditions. Method and Materials: A total of 32 permanent teeth in 4 healthy children with hypocalcified amelogenesis imperfecta were restored with strip crowns and composite resin. Teeth on the left side of the jaw were selected as the control group, and teeth on the right side of the jaw were selected as the treatment group. In the treatment group, a solution of 5% sodium hypochlorite was applied for 1 minute after acid conditioning of tooth surfaces. Clinical success was determined by USPHS modified Ryge criteria up to 36 months. Results: The deproteinization procedure had no effect on the anatomic form of the restorations. The cervical integrity of the restorations in both groups showed inferior results after 36 months compared to baseline. For both groups, no recurrence of caries was observed. Conclusion: The deproteinization had no significant effect on the success of the adhesive restorations; however, composite restorations were clinically successful in children affected by hypocalcified amelogenesis imperfecta in long-term follow-up. Keywords: composite restorations, deproteinization, hypocalcified amelogenesis imperfecta

Objectives: To investigate if the onset of primary herpetic gingivostomatitis (PHG) is shifting toward an adult age and compare the clinical characteristics of PHG between children and adults. Method and Materials: The charts of patients diagnosed with PHG in an oral medicine clinic in Bucharest, Romania, over a 10-year period were revisited. Diagnosis was based on history, clinical data, and laboratory confirmation (Tzanck cytology, polymerase chain reaction [PCR], or immunofluorescence). Seventy-three cases (38 females, 35 males) were included. The age range was between 22 months and 53 years, with a mean age of 18.6 years. All patients were healthy with no suspicion of HIV infection or immunodeficiency. Results: Nearly 48% (47.94%) of the sample were in the young adult group. General symptoms (fever, malaise, and lymphadenopathy) were equally present in children and adults. The most involved areas were the gingiva, vermilion border, and tongue. No differences in the extent of lesions were observed between children and adults. Inflammatory gingivitis and pharyngotonsillitis were more frequent in children than in adults although their frequency was less than expected. Conclusions: PHG was more frequently observed in young adults than in children. No significant differences between children and adults in the severity of infection were observed. Most of the patients presented widespread lesions. Keywords: gingivostomatitis, oral mucosa, primary herpes

Objective: To assess the influence of material selection (porcelain versus composite resin) for overlay-type restoration of endodontically treated molars and its effect on the in vitro fatigue resistance and failure mode. Method and Materials: A standardized tooth preparation was applied to 30 extracted molars, including root canal treatment, 3-mm coverage of all cusps, a mesial box 1.5 mm below the cementoenamel junction (CEJ), a distal box in enamel, a glass-ionomer base, and immediately sealed dentin. Using the Cerec machine (Sirona), all teeth were restored with an overlay of standardized thickness and occlusal anatomy. Fifteen restorations were milled in the ceramic Vita MKII block (Vident) and the other 15 using the composite resin Paradigm MZ100 block (3M ESPE). The intaglio surfaces of the ceramic restorations were etched and silanated. The intaglio surfaces of the composite resin overlays were airborne-particle abraded and silanated. Preparations were airborne-particle abraded and etched before restoration insertion. All restorations were adhesively luted with an adhesive resin (Optibond FL, Kerr) and a light-curing composite resin (Filtek Z100, 3M ESPE). Cyclic isometric chewing (5 Hz) was simulated, starting with a load of 200 N (5,000 cycles), followed by stages of 400, 600, 800, 1,000, 1,200, and 1,400 N at a maximum of 30,000 cycles each. Samples were loaded until fracture or to a maximum of 185,000 cycles. Results: MKII overlays fractured at a mean load of 1,147 N, and none of them withstood all 185,000 loading cycles (survival = 0%); with MZ100, the survival rate was 73%. With MKII, 40% of the fractures ended below the CEJ; with MZ100, only 25% did. Conclusions: Composite resin MZ100 increased the fatigue resistance of overlay-type restorations in endodontically treated molars when compared to porcelain MKII. The efficiency of the bond strategy (immediate dentin sealing) was demonstrated by the absence of adhesive failures. Keywords: Cerec, composite resin, endodontically treated molars, fatigue resistance, overlay restorations, porcelain

Ewing sarcoma is a highly malignant neoplasm, which very rarely involves the head and neck region. Only a few cases have been reported in the maxila or palate. This case is being reported for its rarity. A patient presented to the Department of Oral Pathology, Faculty of Dental Sciences, CSM Medical University, Lucknow, India, with a lesion expanding the nasal cavity and posteriorly reaching up to the anterior border of nasopharynx and inferiorly causing the destruction of the hard palate extending into the oral cavity. The biopsy specimen histopathologically revealed undifferentiated malignant neoplasm, and the definitive diagnosis of Ewing sarcoma was made with immunohistochemistry. The patient underwent surgical excision of the lesion followed by radiotherapy and chemotherapy. Keywords: CD99, Ewing sarcoma, malignant tumor, maxilla

Objective: To evaluate the in vivo antimicrobial activity of different forms of application of chlorhexidine digluconate (CHX). Method and Materials: A group of 10 volunteers performed mouth rinsings with a 0.2% and 0.12% solution of CHX and applied CHX in the form of a 0.2% gel, a 0.2% and a 0.12% spray and a swab impregnated with a 0.2% solution. Samples of saliva were taken at baseline; 30 seconds; and 1, 3, 5, and 7 hours after each application. An epifluorescence microscopy technique (BacLight Live/Dead stain) was used to evaluate bacterial vitality. Results: Bacterial vitality under basal conditions was 92%. At 30 seconds after CHX application, the lowest levels of viable bacteria were detected with the 0.2% and 0.12% solutions (1% and 8%, respectively). After 3 hours, the percentage of live bacteria achieved with the gel and sprays was similar to the basal figures (80% to 91%). At 7 hours, bacterial vitality recovered basal percentages, except with the 0.2% solution (77%). Conclusion: The 0.2% solution of CHX had the greatest sustained antimicrobial effect on the salivary flora, confirming the influence of the concentration and form of application on CHX substantivity. Keywords: chlorhexidine, oral flora, saliva, substantivity

Objective: To evaluate the microtensile bond strength of 2 adhesive systems (Adper Single Bond Plus [3M ESPE] and Clearfil SE Bond [Kuraray]) to carious or normal dentin, with or without previous treatment with Nd:YAG laser or Nd:YAG laser associated with fluoride. Method and Materials: Dentin surfaces of 60 human third molars were exposed. Teeth were divided into 12 groups; groups 1 to 6 were submitted to pH cycling for artificial caries, and groups 7 to 12 remained with normal dentin. Dentin surfaces received 3 treatments: laser Nd:YAG irradiation (60 mJ, 15 Hz, and 0.9 W) for 1 minute; laser Nd:YAG irradiation associated with fluoride in gel; and no treatment (controls). In experimental groups, adhesive systems were applied in accordance with the manufacturers' instructions, and a composite resin block (Filtek Z250, 3M ESPE) was made incrementally for the microtensile bond strength test. The teeth were sectioned serially in both x and y directions, and sticks were submitted to microtensile bond strength testing in a universal testing machine. Results: According to ANOVA and Tukey (P .05), the highest mean bond strengths were obtained in groups of normal dentin treated with Clearfil SE Bond (40.65 MPa) and Single Bond (34.2 MPa). The presence of carious dentin significantly decreased the mean bond strengths of the 2 adhesive systems whether or not they were previously laser irradiated. Nevertheless, Clearfil SE Bond presented the best microtensile bond strength on an irradiated surface. Moreover, laser irradiation associated with fluoride also decreased the bond strength values of the 2 adhesive systems. Conclusion: After excavating a cavity with caries-affected dentin, the use of Nd:YAG laser followed by a self-etching adhesive system is the best clinical choice when considering bond strength, compared with the total etching- based system and laser. Keywords: caries, dentin, dentin-bonding agents, laser, tensile strength

Objective: The presence of a biofilm is necessary for both initiation and progression of dental caries. Silver-based preparations incorporated into, or applied onto, various materials designed for medical use have been shown to be effective in inhibiting biofilm formation. The purpose of this in vitro study was to measure whether a topical application of diamine silver fluoride (AgF) followed by potassium iodide (KI) on partially demineralized dentin affected the formation of a Streptococcus mutans biofilm. Method and Materials: Forty partially demineralized dentin disks were divided into 4 groups as follows: 10 disks as a control, 10 disks treated with AgF followed by KI, 10 disks treated with KI, and 10 disks treated with AgF. The outer surfaces of the disks were examined with a scanning electron microscope. Cross sections of the disks were subjected to electron probe microanalysis (EPMA) to determine the levels of calcium, phosphorous, silver, and fluoride in the dentin. Results: An S mutans biofilm covered the entire exposed surfaces of all control and KI-treated disks. No discernible bacterial biofilm was detected on disks treated with AgF or AgF/KI. Detectable amounts of silver and fluoride were found up to 450 µm in the AgF and AgF/KI sections. Conclusions: Demineralized dentin disks treated with AgF and AgF/KI prevented the formation of an S mutans biofilm and were significantly more resistant to further demineralization than the control and KI-treated disks over the experimental period. The presence of silver and fluoride in the outer layers of the disks treated with AgF and AgF/KI was the likely cause of the prevention of biofilm formation. Additional studies are required before any clinical recommendations can be made. Keywords: biofilm, demineralized dentin, potassium iodide, silver fluoride, Streptococcus mutans

Imaging, along with clincial examiniation, plays a key role in determining the presence and extent of bisphosphonate-related osteonecrosis of the jaw (BRONJ). In this case, conebeam computerized tomography (CBCT) was used to detect a large sequestrum and hyperstotic bone, leading to a diagnosis of bisphosphonate-related osteonecrosis of the jaw in a patient with a history of oral bisphosphonate use for treatment of osteoporosis. The radiographic features of this case of BRONJ are discussed. Keywords: BRONJ, CBCT, extractions, marginal periodontitis, radiographs, sequestrum

Cystadenomas are a rare, painless, and slow-growing benign epithelial tumor of the salivary gland. This article describes the case of a papillary cystadenoma in the lower lip of a 46- year-old man. The lesion was removed using a carbon dioxide laser, and there were no signs of recurrence 1 year postoperatively. Keywords: carbon dioxide laser, cystadenoma, salivary gland