Effects on smear layer and debris removal with varying volumes of 17% REDTA after rotary instrumentation

The purpose of this study was to quantify the volume of 17% ethylene diamine tetra-acetic acid (EDTA) needed to efficiently remove the smear layer after rotary instrumentation, and to determine if additional irrigation has any effect on debris removal. Forty single canal teeth were instrumented with ProFile GT rotary instruments. Experimental groups were irrigated with 1, 3, or 10 ml of 17% EDTA for 1 min, followed by a final rinse with 3 ml of 5.25% sodium hypochlorite (NaOCl). Samples were scored for debris remaining and examined under SEM to determine quality of smear layer removal. There were no significant differences among groups when comparing either debris remaining or quality of smear layer removal. EDTA irrigation volume greater than 1 ml did not improve debris removal. Efficient removal of the smear layer was accomplished with a final rinse of 1 ml of 17% EDTA for 1 min, followed by 3 ml of 5.25% NaOCl.     

Advances in skeletal tissue engineering with hydrogels

OBJECTIVES: Tissue engineering has the potential to make a significant impact on improving tissue repair in the craniofacial system. The general strategy for tissue engineering includes seeding cells on a biomaterial scaffold. The number of scaffold and cell choices for tissue engineering systems is continually increasing and will be reviewed. DESIGN: Multilayered hydrogel systems were developed to coculture different cell types and develop osteochondral tissues for applications including the temporomandibular joint. EXPERIMENTAL VARIABLE: Hydrogels are one form of scaffold that can be applied to cartilage and bone repair using fully differentiated cells, adult and embryonic stem cells. OUTCOME MEASURE: Case studies represent an overview of our laboratory's investigations. RESULTS: Bilayered scaffolds to promote tissue development and the formation of more complex osteochondral tissues were developed and proved to be effective. CONCLUSION: Tissue engineering provides a venue to investigate tissue development of mutant or diseased cells and potential therapeutics.     

Non-viral-mediated gene therapy approaches for bone repair

OBJECTIVES: Bone repair strategies continue to be developed for alternatives to autografting, allogeneic implants of banked bone, and other bone substitutes. Efforts have included the delivery of potent growth and/or differentiation factors and the use of gene therapy. For bone regeneration, gene therapy is the delivery, uptake and expression of DNA that has been localized to a wound bed. The objective of the current study is to investigate methods to enhance non-viral-mediated means of gene uptake and expression for use in bone regeneration. METHODS: Several types of DNA-polymer complexes, either applied directly to baby hamster kidney (BHK) cells, or released from a porous, resorbable gene-activated matrix (GAM), were evaluated in vitro for their ability to transfect cells with a circular plasmid DNA construct expressing green fluorescent protein. Complexes included conjugates containing a lipophilic reagent, liposomes, poly-ethyl-oxazoline, and poly-ethyleneimine (PEI). Data were subjected to analysis of variance and Fisher's protected least significant difference for multiple comparisons with significance established at p < 0.05. RESULTS: Transfection efficiencies of the liposome and PEI complexes improved in vitro when released from resorbable GAMs. The lipophilic reagent FuGene 6 demonstrated abundant uptake and expression in the initial 1- and 2-day evaluation periods. In contrast, the DNA-liposome and PEI GAM complexes demonstrated a sustained release, uptake and expression by the BHK cells at the 2-, 4-, and 7-day, and 4- and 7-day evaluation intervals, respectively. CONCLUSION: GAM technology appears to improve the functional stability and release duration of incorporated DNA-polymer complexes in the present in vitro studies. The ongoing objective of our research is to develop a localized treatment to improve the uptake and expression of plasmid DNA by non-viral-mediated gene therapy.     

Development of methods to enhance extrinsic tooth discoloration for comparison of toothpastes. 2. Two-product clinical study

BACKGROUND: Extrinsic staining of teeth is considered to be unsightly and a number of 'whitening' toothpastes have been formulated to inhibit or remove such tooth discoloration. The aim of this study was to compare the stain prevention of two toothpastes. METHOD: The study was a single-blind, randomised, placebo-controlled, crossover design, balanced for residual effects involving 24 healthy dentate volunteers. The treatments were as follows: (1) a whitening toothpaste product, (2) an experimental toothpaste formulation and (3) water. For each 4-day rinse period, subjects were rendered stain free on the teeth and tongue. Approximately on the hour from 09:00 to 16:00 hours, subjects rinsed with chlorhexidine mouth rinse for 1 min followed by warm black tea for 1 min. The treatment interventions were at 09:00 and 16:00 hours and before the chlorhexidine rinse. The toothpastes were rinsed as 3 g/10 ml water slurries and water as a 10 ml rinse each for 2 min. On day 5, subjects were scored for tooth and tongue stain intensity and area, and the product of these was calculated. The washout period was at least 9 days. RESULTS: Treatment differences for the teeth were highly significant but not for the tongue. Paired contrasts for tooth stain intensity, area and product were mostly all significantly in favour of reduced staining by the experimental formulation compared with water and the whitening product. There were no significant differences between water and the whitening product. CONCLUSIONS: Using a forced dietary staining method, the data support a tooth stain-inhibitory/-removal action for the experimental formulation, but not the whitening product.     

Transverse craniofacial features and their genetic predisposition in families with nonsyndromic unilateral cleft lip and palate.

OBJECTIVE: The purpose of this study was to evaluate the transverse craniofacial form in families with nonsyndromic cleft lip and palate (NSCLP). It was hypothesized that affected as well as noncleft NSCLP family members are characterized by a common array of craniofacial features that differ from the general population. DESIGN: This was a prospective cross-sectional investigation that included affected children with NSCLP and their noncleft parents and siblings. PATIENTS, PARTICIPANTS: A total of 114 subjects (14 affected girls, 17 affected girls, 15 unaffected male siblings, 10 unaffected female siblings, 29 unaffected biological mothers, and 29 unaffected biological fathers) were included. Subject records comprised of posteroanterior cephalometric radiographs obtained from all 114 subjects. MAIN OUTCOME MEASURES: The width of midfacial structures, including the orbit and nose, was increased in NSCLP families, compared with published norms. Interestingly, the face was disproportionally wider in relation to total facial height. The transverse craniofacial form of children with or without clefts significantly correlated with that of their parents. Mothers displayed strong correlation with their affected and unaffected sons, whereas fathers correlated to their daughters, suggesting a possible sex-linked developmental influence. CONCLUSION: Better understanding of the genetic inheritance of craniofacial features associated with cleft lip and palate may ultimately contribute to the development of cleft risk assessment methods.     

Pedicled sandwich plasty: a variation on alveolar distraction for vertical augmentation of the atrophic mandible

We describe a method of vertical augmentation of an edentulous mandible that causes minimal weakening of bone and disturbance of sensation.     

Prevalence of early childhood caries among First Nations children, District of Manitoulin, Ontario

Background. Epidemiological studies of Aboriginal communities in Canada and Native American populations in the United States have reported that early childhood caries (ECC) is highly prevalent. The purpose of this study was to determine the prevalence of ECC and dental caries in the First Nations population of 3‐ and 5‐year‐old children in the District of Manitoulin, Ontario to assist in developing effective dental health promotion strategies. Methods. All 3‐ and 5‐year‐old children in elementary schools and day‐care centres in seven First Nation communities were eligible for the survey examination. Three‐year‐old children at home and 5‐year‐old children attending school off‐reserve in six of the communities were also eligible for epidemiological survey examination of oral health status including caries, gingival and soft tissue conditions. Cases of ECC were defined as children with caries or restorations on two or more primary maxillary incisors or canines or those having a total decayed, missing, filled primary teeth (dmft) score of 4 or greater. Results. A total of 87 children (59% 5 years old, 54% females) were examined. Seventy‐four per cent of children had one or more carious lesions. Forty‐five cases of ECC were found, a prevalence of 52%. The mean dmft score for cases was 7·5 (95% CI 6·5–8·4) and 0·8 (95% CI 0·5–1·1) for non‐cases (P < 0·001). Boys in both age groups were more likely to be affected by ECC than girls. Conclusion. Our results indicate that dental caries and ECC are highly prevalent in this population, with ECC cases having 6.7 more dmft than non‐cases.     

The effects of an immediately pre-surgical chlorhexidine oral rinse on the bacterial contaminants of bone debris collected during dental implant surgery

Dental implant surgery produces bone debris that can be used in the "simultaneous augmentation" technique. Although this debris is contaminated with oral bacteria, a stringent aspiration protocol has been shown to reduce the levels of contamination. Chlorhexidine mouthrinse is a well-proven antibacterial rinse that has been shown to reduce infectious complications associated with dental implants. This study examined the effect of pre-operative rinsing with a 0.1% chlorhexidine digluconate mouthrinse on the bacterial contaminants present in collected bone debris bone (CBD). Twenty partially edentate patients were randomly allocated into equal groups and underwent bone collection using the Frios Bone Collector (FBC) during the insertion of two dental implants. In group T a pre-operative chlorhexidine rinse was used, whilst in group C sterile water was used. For both groups, a stringent bone collection protocol was used. Bone samples were immediately transported for microbial analysis. Colonial and microscopic morphology, gaseous requirements and identification kits were utilised for identification of the isolated microbes. Thirty-nine species were identified including a number associated with disease, in particular Actinomyces odontolyticus, Clostridium bifermentans, Prevotella intermedia, and Propionibacterium propionicum. Samples from group T (chlorhexidine mouthrinse) yielded significantly fewer organisms (P < 0.001) than in group C (sterile water mouthrinse). Gram-positive cocci dominated the isolates from both groups. It is concluded that if bone debris is to be used for the purpose of immediate simultaneous augmentation, a preoperative chlorhexidine mouthrinse should be utilised in conjunction with a stringent aspiration protocol to reduce further the bacterial contamination of CBD.     

Clinical comparison of bioactive glass bone replacement graft material and expanded polytetrafluoroethylene barrier membrane in treating human mandibular molar class II furcations

BACKGROUND: Class II furcations present difficult treatment problems and historically several treatment approaches to obtain furcation fill have been used. METHODS: The response of mandibular Class II facial furcations to treatment with either bioactive glass (PG) bone replacement graft material or expanded polytetrafluoroethylene (ePTFE) barrier membrane was evaluated in 27 pairs of mandibular molars in 27 patients with moderate to advanced periodontitis. Following initial preparation, full thickness flaps were raised in the area being treated, the bone and furcation defects debrided of granulomatous tissue, and the involved root surfaces mechanically prepared and chemically conditioned. By random allocation, PG or ePTFE was placed into or fitted over the furcations, packed or secured in place, and the host flap replaced or coronally positioned with sutures. Postsurgical deplaquing was performed every 10 days leading up to ePTFE removal at about 6 weeks. Continuing periodontal maintenance therapy was provided until surgical reentry at 6 months for documentation and any further necessary treatment. RESULTS: Direct clinical measurements demonstrated essentially similar clinical results with both treatments for bone and soft tissue changes. There were no statistically or clinically significant differences (e.g., mean horizontal furcation fill 1.4 mm PG, 1.3 mm ePTFE; mean percent horizontal furcation fill 31.6% PG, 31.1% ePTFE, both P>0.85). Seventeen of the PG treated and 18 of the ePTFE furcations became Class I clinically and 1 furcation completely closed clinically with each treatment. Intrapatient comparisons showed similar horizontal furcation responses with both treatments. CONCLUSION: The findings of this study suggest essentially equal clinical results with PG bone replacement graft material and e-PTFE barriers in mandibular molar Class II furcations. PG use was associated with simpler application and required no additional material removal procedures.