The anti-microbial effect against enterococcus faecalis and the compressive strength of two types of mineral trioxide aggregate mixed with sterile water or 2% chlorhexidine liquid

The purpose of this in vitro study was 2-fold: First, to compare the antimicrobial effect of gray and tooth-colored mineral trioxide aggregate (MTA) when mixed with sterile water or 2% chlorhexidine. Second, to compare the compressive strengths of the MTA/chlorhexidine versus MTA/sterile water samples. The antimicrobial effect test was accomplished by placing freshly mixed MTA samples on agar plates inoculated with Enterococcus faecalis and comparing the zones of inhibition at 24 hours. In the compressive strength test, MTA pellets were allowed to set for 72 hours and then compressed to fracture by using an Instron testing machine. Values were recorded and compared. In the antimicrobial effect experiment, the zones of inhibition were significantly larger for samples mixed with 2% chlorhexidine. In the compressive strength study, statistical evaluation showed no significance due to variability. However, data revealed that MTA mixed with sterile water always had higher compressive strengths than MTA mixed with chlorhexidine.     

Review of the literature and report of a case of a dermoid cyst.

This article presents a large dermoid cyst discovered in the floor of the mouth of a young male patient. The lesion was clinically detected by manual palpation and confirmed by the use of magnetic resonance imaging. Treatment of this case was by surgical removal of the dermoid cyst. The patient recovered without any complications or evidence of re-occurrence of the cyst.     

Alveolar bone grafting in patients with complete clefts: a comparative study between secondary and tertiary bone grafting.

OBJECTIVE: This investigation evaluated the results of alveolar bone grafting in patients with complete clefts, comparing secondary alveolar bone grafting (during the mixed stage of dentition) versus tertiary bone grafting (after completion of the second stage of dentition). DESIGN: This was a retrospective study. Of 140 osteoplasties, which all were operated according to the same standardized surgical technique, a clinical and roentgenological follow-up investigation was carried out in a collective of 85 osteoplasties. Clinically we searched for oronasal fistulae, assessed the periodontal status, determined the extent of the gingival attachment in the area of the osteoplasty, and searched for vertical growth disturbances in the area of the osteoplasty. Roentgenologically the height of the alveolar bone in the former clefted area was ascertained. SETTING: Records were obtained from a clinical and radiological study of the Department of Oral and Maxillofacial Surgery of the Medical University of Hannover (Germany). INTERVENTIONS: All patients were operated with the same standardized surgical method. The osteoplastic bridging of the alveolar cleft was performed via a vestibular gingival marginal incision and exclusively by grafting of cancellous bone from the iliac crest. RESULTS: The best results of alveolar bone grafting in cases of secondary osteoplasty were obtained when the lateral incisor or canine had grown into the transplant and had led to a functional stress of the transplanted bone. Approximately good results were to be found in tertiary osteoplasty when the transplanted bone had been stressed functionally through a dental implant. Comparing the secondary with the tertiary osteoplasty, there was a trend of lower resorption in secondary osteoplasty. CONCLUSIONS: Secondary osteoplasty should represent an integral component of any concept for the comprehensive treatment of patients with cleft lip and palate.     

Apicomarginal defects in periradicular surgery: classification and diagnostic aspects

The prognosis of periradicular surgery is affected by the amount and location of bone loss. Apicomarginal defects are localized bony defects encompassing the total root length, and periradicular surgery on these teeth is associated with a lower success rate. This paper reviews the etiology, pathogenesis, and morphology of apicomarginal defects as encountered in periradicular surgery on the basis of a series of 24 consecutively treated patients. Periodontal data were recorded before surgery in all patients, and apicomarginal defects were diagnosed after flap reflection or, if applicable, apicoectomy. On the basis of the findings in these cases and on theoretic considerations, a classification system for apicomarginal defects with potential therapeutic and prognostic implications is presented and several criteria for differential diagnosis are discussed.     

The early development of palatal rugae in the rat

The palatal rugae in rats are contained in two of three zones of morpho-differentiation and develop around the time of palatal closure. Previous studies in humans and pigs have been based on crown-rump lengths but now controlled breeding in rats has allowed exact timing to be established. Twenty-nine female DB IX rats were fertilized and sacrificed in a controlled procedure and foetuses processed for light microscopy and SEM. Serial sagittal sections were made and stained with haematoxylin and eosin and Verhoef's stains. At day 13 the palate was open and no rugae were visible. At day 14 the palatal shelves had started to migrate medially and the ante-molar rugae appeared. At day 15 the palatal shelves were touching and the inter-molar rugae became visible, and at day 16 fusion was all but complete and the definitive rugal pattern established. The development and differentiation is more advanced than in humans and it is concluded that the rugae probably have a role to play in the oral function of animals whereas in humans they are becoming attenuated and the development timetable is retarded because of redundancy.     

Condylar position following mandibular advancement: Its relationship to relapse

Forty-one patients who elected to receive a bilateral sagittal osteotomy to advance the mandible were examined clinically and radiographically to assess condylar position preoperatively and at three specific times post-operatively. Parameters designed to measure changes in condylar and distal fragment position were located on tracings and digitized for statistical analysis. Changes in distal fragment position included advancement and clockwise rotation during the surgical interval and significant posterior relapse with continued clockwide rotation during the period of maxillomandibular fixation. A small amount of counterclockwise rotation associated with interocclusal splint removal was seen following fixation release. No significant condylar movement was seen during the surgical interval. During the period of maxillomandibular fixation, both condyles exhibited a significant superior movement, and the left condyle also moved posteriorly. No changes in condylar position were noted following release of fixation. The clinical significance of these condylar movements is not clear. Despite minimal changes, 18 patients, six of whom had had no preoperative symptoms and one of whom had exhibited reciprocal clicking, complained of temporomandibular joint pain or noise postoperatively. This suggests that maintenance of condylar position during surgery may not prevent temporomandibular joint dysfunction. In addition, the observed 37% relapse in surgical advancement in the absence of significant condylar distraction implies the interaction of other factors in the relapse process.     

Correlation of scanning and transmission electron microscopy of human dentinal tubules

Areas of human dentine were examined first with the scanning electron microscope (SEM) and subsequently with the transmission electron microscope (TEM). Structures observed in dentinal tubules from outer dentine by SEM were identified by TEM as electron-dense structures lining the tubules and not as odontoblast processes. These structures, termed lamina limitans, correspond to the previously described inner hypomineralized lining of dentinal tubules.     

Treatment of proximal caries lesions by tunnel restorations.

OBJECTIVE: The "tunnel technique" may be used as an alternative to the "conventional" class II preparation for the treatment of proximal dentin caries. The purpose of this article was to summarize and discuss the available information concerning the tunnel technique and the clinical success of tunnel restorations. METHODS: Information from original scientific full papers or reviews listed in PubMed (search term: tunnel preparation or tunnel restoration) were included in the review. Papers dealing with endodontic or periodontal topics and case reports were not taken into consideration. Clinical studies were included when at least 20 restorations could be followed-up for at least 24 months. In vivo- and in vitro-studies were excluded when the number of restorations under observation or the decision criteria were not clearly defined. Insufficient data about tunnel restorations in the primary dentition do not allow for analysis. RESULTS: Both effectiveness of caries removal and marginal ridge strength are reduced in tunnel restorations compared to conventional class II. Glass-ionomer tunnel restorations exhibit an annual failure rate of 7-10%. Therefore, the main reasons for clinical failure are marginal ridge fracture, recurrent caries and progression of demineralization. However, clinical studies indicate that composite but not glass-ionomer tunnel restorations might be a promising alternative. CONCLUSION: Tunnel restorations filled with glass-ionomer cements exhibit technical deficiencies and a limited life-span compared to conventional class II composite or amalgam restorations and could not be recommended as an alternative preparation for proximal carious lesions. Promising clinical results of composite tunnel restorations need to be confirmed by long-term studies.     

Review on fluoride-releasing restorative materials--fluoride release and uptake characteristics, antibacterial activity and influence on caries formation.

OBJECTIVES: The purpose of this article was to review the fluoride release and recharge capabilities, and antibacterial properties, of fluoride-releasing dental restoratives, and discuss the current status concerning the prevention or inhibition of caries development and progression. METHODS: Information from original scientific full papers or reviews listed in PubMed (search term: fluoride release AND (restorative OR glass-ionomer OR compomer OR polyacid-modified composite resin OR composite OR amalgam)), published from 1980 to 2004, was included in the review. Papers dealing with endodontic or orthodontic topics were not taken into consideration. Clinical studies concerning secondary caries development were only included when performed in split-mouth design with an observation period of at least three years. RESULTS: Fluoride-containing dental materials show clear differences in the fluoride release and uptake characteristics. Short- and long-term fluoride releases from restoratives are related to their matrices, setting mechanisms and fluoride content and depend on several environmental conditions. Fluoride-releasing materials may act as a fluoride reservoir and may increase the fluoride level in saliva, plaque and dental hard tissues. However, clinical studies exhibited conflicting data as to whether or not these materials significantly prevent or inhibit secondary caries and affect the growth of caries-associated bacteria compared to non-fluoridated restoratives. SIGNIFICANCE: Fluoride release and uptake characteristics depend on the matrices, fillers and fluoride content as well as on the setting mechanisms and environmental conditions of the restoratives. Fluoride-releasing materials, predominantly glass-ionomers and compomers, did show cariostatic properties and may affect bacterial metabolism under simulated cariogenic conditions in vitro. However, it is not proven by prospective clinical studies whether the incidence of secondary caries can be significantly reduced by the fluoride release of restorative materials.