Root surface conditioning with nicotine or cotinine reduces viability and density of fibroblasts in vitro

The purpose of study was to evaluate fibroblast attachment and cellular morphology on root surfaces chemically conditioned with nicotine or cotinine. A secondary objective was to determine if mechanical scaling and root planning of these chemically conditioned surfaces would alter cellular attachment. Root surface dentin specimens were prepared from uniradicular teeth of non-smoking patients. Specimens were randomly assigned to two experimental groups: no treatment (chemical conditioning only) and scaling and root planning after conditioning (SRPC). The concentrations of the tested substances were in the range of 0–1 mg/mL (nicotine) and 0–1 ?g/mL (cotinine). After a 24-h conditioning period, dentin slices were incubated with continuous lineage of fibroblastic cells from rat (McCoy cells) for another 24 h. Specimens were prepared for SEM analysis and microphotographs. The statistical analysis of the data indicated significant alteration of cellular morphology on fibroblasts that were grown on root surface exposed to nicotine concentrations greater than 1 ?g/mL. This effect of nicotine was not reduced by SRPC. On the other hand, in the SRPC group cellular density was greater. For cotinine-conditioned specimens, the greater concentrations also led to alteration on morphology, and these alterations were observed in the SRPC group as well. Cotinine did not induce significant changes on cellular density. The results indicated that fibroblasts are negatively influenced by nicotine present on the dentin substrate and also that scaling may reduce these effects. Cotinine treatment on root surfaces may alter cell morphology and density but these effects were less severe than that promoted by nicotine, and were not affected by scaling.     

Removable partial denture abutments restored with all-ceramic surveyed crowns.

All-ceramic crowns are used as alternatives to conventional metal-ceramic crowns for the restoration of single teeth. Traditionally all-ceramic restorations possessed physical properties that contraindicated their use in many treatment situations. The strength that zirconia ceramics exhibit seems to support the hypothesis that, in specific situations, an all-ceramic crown may be used to restore removable partial denture (RPD) abutments in areas previously reserved for metal or metal-ceramic restorations. Abutments for RPDs may now be fabricated with Procera AllZirkon with the classically prepared guide planes and rest seats. This article provides an overview of a technique for the fabrication of a zirconia-based crown to be used in conjunction with removable partial dentures using the Procera CAD/CAM technology.     

Dental treatment for children with chronic idiopathic thrombocytopaenic purpura: a report of two cases

Idiopathic thrombocytopaenic purpura (ITP) is the most common acquired bleeding disorder occurring in previously healthy children. The condition is benign and self-limiting, with a high possibility of recovery. Only 15-30% of children with acute ITP develop the chronic form. Clinically, ITP presents with petechiae, ecchymoses, haematomas, epistaxis, haematuria, mucocutaneous bleeding, and occasionally, haemorrhage into tissues. Oral manifestations include spontaneous gingival bleeding, petechiae or haematomas of the mucosa, tongue or palate. Two paediatric case reports are described concerning female patients diagnosed with chronic ITP. Oral findings and dental procedures are described. Standard dental treatment was performed with a platelet count higher than 50,000/mm3. The importance of adequate dental plaque control techniques in order to prevent inflammation, potential bleeding and infection in these patients is emphasized. The paediatric dentist must be aware of the clinical appearance of ITP in order to recognize the condition and successfully manage the patient.     

Influence of oral characteristics and food products on masticatory function

Mastication is a complex process that involves activities of the facial muscles, the elevator and suprahyoidal muscles, and the tongue. These activities result in patterns of rhythmic mandibular movements, food manipulation, and the crushing of food between the teeth. Saliva facilitates mastication by moistening food particles, making a bolus, and assisting swallowing, whereas food consistency modifies masticatory forces, the mandibular jaw movements, the duration of the mastication cycle, and the number of cycles preceding the first swallow. Jaw elevator EMG activity research shows a clear relation between muscular activity and food properties. The teeth, masticatory muscles, and temporomandibular joints are also important because together they form the mechanism by which the food particles are fragmented. Hard and dry foods require more chewing cycles and a longer time in the mouth until swallowing for sufficient breakdown to take place and for enough saliva to be added to form a coherent bolus safe enough for swallowing. Product characteristics, the amount of saliva, dentition, and bite force affect the chewing performance. This study presents an update and synopsis of the effects of saliva, food, dentition, muscle force, and temporomandibular disorders on the masticatory process.     

Gingival squamous cell carcinoma: diagnostic delay or rapid invasion?

BACKGROUND: The similarity between gingival squamous cell carcinoma (GSCC) and more common periodontal lesions may lead to a delay in diagnosis or misdiagnosis. Neoplastic lesions of gingival tissues are frequently diagnosed at an advanced stage. METHODS: To assess the relative time from when patients first become aware of the problem to histopathologic diagnosis (total diagnostic time), 59 consecutive oral cancer cases were examined in this study. The following variables were considered: age, gender, smoking habits, tumor stage at diagnosis, and total diagnostic time. The median of the patients' total diagnostic time (1.5 months) was used as a cutoff point to distinguish between delayed and non-delayed cases. Analysis of the variables was undertaken using the Student t test and chi2 test, with a 95% confidence interval (CI). RESULTS: The total diagnostic time was <1.5 months for 75% of gingival carcinomas, 50% of tongue carcinomas, and 78% of floor-of-the-mouth carcinomas. It was >1.5 months for 25% of gingival carcinomas, 50% of tongue carcinomas, and 21% of floor-of-the-mouth carcinomas. No significant differences in time before diagnosis were found when gingival cancers were compared to other oral tumors (chi2=0.21; 95% CI=-0.40 to 0.26). However, by the time of diagnosis, gingival cancers had invaded adjacent structures more frequently than other oral cancers (chi2=13.51; 95% CI=0.18 to 0.85). CONCLUSIONS: The gingival location of oral squamous cell carcinoma (OSCC) was associated with advanced stages at the time of diagnosis, due to early invasion of contiguous bone tissue (T4-primary tumor). This would indicate that even earlier referral and diagnosis are necessary.     

Effect of surface conditioning and restorative material on the shear bond strength and resin-dentin interface of a new one-bottle nanofilled adhesive.

OBJECTIVES: To determine the effect of different combinations of surface conditioning (DeTrey Conditioner 36, NRC, no etching) and restorative materials (Dyract AP, Spectrum TPH) on the shear bond strength of Prime and Bond NT to enamel and dentin, and to characterize the resin-dentin interface produced by these combinations. METHODS: Shear bond strength was tested on 30 enamel and 30 dentin flat labial surfaces of extracted bovine teeth. The enamel and dentin specimens were randomly assigned to six groups of five teeth each and treated using different combinations of surface conditioners and restorative materials with Prime and Bond NT. Scanning electron microscope (SEM) observation of argon-ion-etched specimens was done to evaluate the resin-dentin interface. RESULTS: The type of surface conditioning and restorative material had significant effects on dentin bond strengths. Etching the dentin prior to application of Prime and Bond NT significantly increased bond strength and caused formation of a hybrid layer for Spectrum TPH. For Dyract AP, dentin etching generally did not improve bond strength despite the formation of a hybrid layer. On enamel, Prime and Bond NT had consistently high bond strengths on etched specimens. SIGNIFICANCE: The results showed that Dyract AP and Spectrum TPH, when used with Prime and Bond NT have different bonding mechanisms and the effect of surface conditioning on their shear bond strength differs. Clinicians should be aware of these effects in order to optimize bonding.