Clinical evaluation of the anti-plaque effect of a commercial chewing gum

OBJECTIVE: The objective of this research was to evaluate the dental plaque control effect of a chewing gum versus brushing with a dentifrice via four clinical studies. METHODOLOGY: Study 1 compared a commercial chewing gum (Colgate Dental Gum, CDG) with a water control after 24 hours post-brushing; Studies 2 and 3 compared CDG to two different brands of commercially available fluoride dentifrices after 24 hours post-brushing; Study 4 examined the anti-plaque effect of CDG plus a regular fluoride dentifrice (Colgate Winterfresh Gel, CWG) versus brushing with CWG alone for five days. The 24-hour clinical tests employed the Modified Gingival Margin Plaque Index (MGMPI), while the Quigley-Hein Plaque Index (QHPI) was used for the five-day study. All studies utilized a randomized, crossover design with a one-week washout period, and were single-blinded to the clinical evaluator. RESULTS: In Study 1, the mean MGMPI score for CDG was significantly lower (p < 0.05) compared to the water control. In Studies 2 and 3, while brushing with regular fluoride dentifrices provided improved plaque control compared to CDG, the chewing gum alone with no tooth brushing delivered a plaque reduction 60% as effective as brushing with a fluoride dentifrice. In Study 4, the group using the combination of chewing with CDG and brushing with CWG provided a significantly lower (p < 0.05) mean QHPI score compared to the group using the dentifrice only, particularly on the hard-to-brush lingual surfaces. CONCLUSIONS: Four clinical studies demonstrated that CDG provides a plaque control benefit. The results suggest that chewing gum may serve as an effective oral hygiene device when brushing may not be possible and, additionally, that chewing gum may serve as an effective adjunct to brushing for enhanced oral health.     

Chondroma of the cheek: A case report

An extremely rare case of soft tissue chondroma occurring in the right cheek of a 47-year-old woman is reported. The localized nodular tumor was encapsulated and composed of hyalinized cartilage with fine calcifications. Most tumor cells were positive for vimentin and S-100 protein, but negative for cytokeratin, factor VIII, and smooth muscle actin. It seems likely that the tumor cells arise from uncommitted mesenchymal stem cells by metaplastic process.     

Effects of pH values of hydrogen peroxide bleaching agents on enamel surface properties

This study investigated the influence of pH values of bleaching agents on the properties of the enamel surface. Sixty freshly extracted premolars were embedded in epoxy resin and mesiodistally sectioned through the buccal aspect into two parts. The sectioned slabs were distributed among six groups (n=10) and treated using different solutions. Group HCl was treated with HCl solution (pH=3.0) and served as a positive control. Group DW, stored in distilled water (pH=7.0), served as a negative control. Four treatment groups were treated using 30% hydrogen peroxide solutions with different pH values: group HP3 (pH=3.0), group HP5 (pH=5.0), group HP7 (pH=7.0), and group HP8 (pH=8.0). The buccal slabs were subjected to spectrophotometric evaluations. Scanning electron microscopy investigation and Micro-Raman spectroscopy were used to evaluate enamel surface morphological and chemical composition alterations. pH value has a significant influence on the color changes after bleaching (p<0.001). Tukey's multiple comparisons revealed that the order of color changes was HP8, HP7>HP5, HP3>HCl>DW. No obvious morphological alterations were detected on the enamel surface in groups DW, HP7, and HP8. The enamel surface of groups HCl and HP3 showed significant alterations with an erosion appearance. No obvious chemical composition changes were detected with respect to Micro-Raman analysis. Within the limitations of this study, it was concluded that no obvious morphological or chemical composition alterations of enamel surface were detected in the neutral or alkaline bleaching solutions. Bleaching solutions with lower pH values could result in more significant erosion of enamel, which represented a slight whitening effect.     

变形链球菌在父子间传播的研究

目的　本实验应用随机引物聚合酶链反应法 (AP PCR)对父子间变链的传播进行研究 ,以期为龋病预防提供新思路和理论依据。方法　随机选取中国沈阳一个幼儿园 10名 3～ 5岁的儿童及其父亲作为研究对象 ,取父亲非刺激性全唾液并刮取儿童牙菌斑 ,进行细菌培养 ,用酚 -氯仿法抽提细菌DNA ,进行PCR反应 ,电泳。结果　儿童共分离出 16个基因型 ,3个与父亲的一致 ,占 18.8%。结论　在中国家庭父子间存在变链传播     

增殖细胞核抗原和Bcl-2蛋白在粘液表皮样癌中的表达及其意义

目的：探讨PCNA、Bcl-2蛋白在粘液表皮样癌中的表达及其相互联系。方法：对33例手术切除的粘液表皮样癌组织标本进行免疫组化染色，结果：24例粘液表皮样癌均显示PCNA阳性，低分化组的PCNA表达较高分化组高（P＜0．05）。Bcl-2为弱阳性表达，高分化组的Bcl-2表达较低分化组高，二组之间的Bcl-2阳性表达水平差异显著性（P＜0．05）。XFYW：PCNA与Bcl-2无明显关系。     

牙槽骨吸收与吸烟状况的研究

目的: 评价不同程度牙槽骨吸收的牙数与每日吸烟量和血浆中cotinine水平的关系。方法: 120名未治疗的慢性牙周炎患者,男 48,女 72,平均年龄 42. 3岁。根据自述的吸烟状况分组。116人检测了血浆cotin ine水平。根据骨吸收达根长的冠 1 /3、中 1 /3和根 1 /3, 牙槽骨吸收分为轻、中、重度骨吸收。结果:cotinine水平与自述的吸烟状况呈正相关(P<0. 001)。重度吸烟组较非吸烟组,中度骨吸收的牙齿数明显增多;而非吸烟组,无骨吸收的牙齿多(P值均<0. 001)。结论:吸烟>10支 /d是牙槽骨吸收牙数增加的重要危险因素。     

Dental resin composites containing ceramic whiskers and precured glass ionomer particles.

OBJECTIVES: Glass ionomer, resin-modified glass ionomer, and compomer materials are susceptible to brittle fracture and are inadequate for use in large stress-bearing posterior restorations. The aim of this study was to use ceramic single crystal whiskers to reinforce composites formulated with precured glass ionomer, and to examine the effects of whisker-to-precured glass ionomer mass ratio on mechanical properties, fluoride release, and polishability of the composites. METHODS: Silica particles were fused onto silicon nitride whiskers to facilitate silanization and to improve whisker retention in the matrix. Hardened glass ionomer was ground into a fine powder, mixed with whiskers, and used as fillers for a dental resin. Four control materials were also tested: a glass ionomer, a resin-modified glass ionomer, a compomer, and a hybrid composite. A three-point flexural test was used to measure flexural strength, modulus, and work-of-fracture. A fluoride ion-selective electrode was used to measure fluoride release. Composite surfaces polished simulating clinical procedures were examined by SEM and profilometry. RESULTS: At whisker/(whisker + precured glass ionomer) mass fractions of 1.0 and 0.91, the whisker composite had a flexural strength in MPa (mean (SD); n = 6) of (196 (10)) and (150 (16)), respectively, compared to (15 (7)) for glass ionomer, (39 (8)) for resin-modified glass ionomer, (89 (18)) for compomer, and (120 (16)) for hybrid composite. The whisker composite had a cumulative fluoride release of nearly 20% of that of the glass ionomer after 90 days. The whisker composites had surface roughness comparable to the hybrid resin composite. SIGNIFICANCE: Composites filled with precured glass ionomer particles and whiskers exhibit moderate fluoride release with improved mechanical properties; the whisker-to-glass ionomer ratio is a key microstructural parameter that controls fluoride release and mechanical properties.     

下颌阻生第三磨牙拔除术后疼痛、张口受限及肿胀之分析

目的：探讨下颌阻生第三磨牙拔除术后的疼痛，张口受限及肿胀与手术难度的关系。方法：收集124例下颌阻生第三磨牙拔除术的病例，按手术难度分为三组，分别于术后第二日及第七日分析三者之间的疼痛，张口受限及肿胀差异。结果：三组的大部分病例均发生了张口受限，疼痛及肿胀反应，术后第二日及第七日三组间张口受限差异无统计学意义，术后第二日，挺出组疼痛分级程度较其它两组轻，而切开组与去骨组疼痛的分级无差异；术后第七日，去骨组仍有疼痛的比例较高，而切开组与挺出组间则无差异，术后第二日及第七日，去骨组及切开组之肿胀分级均较挺出组为高，在去骨组与切开组间则均无差异。结论：下颌阻生第三磨牙拔除术后均有可能发生张口受限，疼痛及肿胀反应，张口受限与手术难度无关，软组织损伤小者。术后疼痛较轻，去骨无加重疼痛，但疼痛缓解较慢，软组织的损伤程度与肿胀的发生及缓解有关联，肿胀与是否去骨并无密切关系。