Estrogen deficiency and periodontal condition in rats: a radiographic and macroscopic study.
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The purpose of this study was to evaluate the impact of ovariectomy-induced estrogen deficiency as a risk factor of periodontal disease in rats. Forty 90-day old female rats were either ovariectomized (OVX; n=20) or sham operated (SHAM; n=20). After 30 days, periodontitis was induced by placement of a cotton ligature around the upper second molars of 10 OVX and 10 SHAM animals. All animals were sacrificed 5 weeks later. Body weight was assessed before all surgical procedures. The left hemimaxillas were removed and the percentage of periodontal bone support was determined radiographically and buccal alveolar bone loss was determined macroscopically using an image-analysis software. Furcation involvement was also evaluated. Data were analyzed statistically by ANOVA at 5% significance level. Within the evaluated period, the ovariectomized rats gained more weight than the sham-operated animals (p<0.001). The animals in which periodontitis was induced had less bone support, greater alveolar bone loss and furcation involvement than those without ligature (p<0.001). However, there was no difference between ovariectomized and sham-operated animals (p>0.05). Based on the findings of this study, estrogen deficiency could not be considered as a risk factor for periodontal disease. (+info)
One-year clinical evaluation of five single-step self-etch adhesive systems in non-carious cervical lesions.
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This study evaluated the clinical performance of five single-step self-etch adhesive systems over a one-year follow-up period in 98 restorations. Independent evaluations were performed at baseline (one week), after three months, six months, and one year, by two trained examiners using the modified US Public Health Service rating criteria. Color match, marginal integrity, anatomical form, surface roughness, marginal or interfacial staining, postoperative sensitivity, and secondary caries were evaluated. Results were analyzed using the Kruskal-Wallis test at a significance level of p<0.05. After one year, the restorations were re-evaluated and 100% retention rate was recorded. No caries were detected in association with any of the restorations. Marginal adaptation was the only measure that showed a slight deterioration over time, and there were no significant differences in this factor among the adhesive systems tested (p=0.464). (+info)
Influence of cervical preflaring on apical file size determination in maxillary lateral incisors.
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The purpose of this study was to investigate the influence of cervical preflaring on determination of the initial apical file in maxillary lateral incisors. Forty human lateral incisors with complete root formation were used. After standard access cavities, a size 06 K-file was inserted into each canal until the apical foramen was reached. The WL (WL) was set 1 mm short of the apical foramen. Four groups (n=10) were formed at random, according to the type of cervical preflaring performed. Group 1 received the initial apical instrument without previous preflaring of the cervical and middle root canal thirds. Group 2 had the cervical and middle root canal thirds enlarged with nickel-titanium Orifice Opener instruments. Group 3 had the cervical and middle root canal thirds enlarged with Gates-Glidden drills. Titanium-nitrite treated, stainless steel LA Axxess burs were used for preflaring the cervical and middle root canal thirds of group 4. Each canal was sized using manual K-files, starting with size 08 files with passive movements until the WL was reached. File sizes were increased until a binding sensation was felt at the WL, and the instrument size was recorded for each tooth. The apical region was then observed under a stereoscopic magnifier, images were recorded digitally and the differences between root canal and maximum file diameters were recorded (in mm) for each sample. Significant differences were found between the groups regarding the anatomical diameter at the WL and the first file to bind the canal (p = 0.01). The major discrepancy was found when no preflaring was performed (0.1882 mm average). Canals preflared with Orifice Opener instruments (0.0485 mm average) and Gates-Glidden drills (0.1074 mm average) also showed great discrepancy. The LA Axxess burs produced the smallest differences between anatomical diameter and first file to bind (0.0119 mm average). Instrument binding technique for determining anatomical diameter at WL was not accurate. Preflaring of the cervical and middle thirds of the root canal improved anatomical diameter determination; the instrument used for preflaring played a major role on determination of the anatomical diameter at the WL. Canals preflared with LA Axxess burs created a more accurate relationship between file size and anatomical diameter. (+info)
Detection of Streptococcus mutans and Streptococcus sobrinus in dental plaque samples from Brazilian preschool children by polymerase chain reaction.
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The purposes of this study were to detect S. mutans and S. sobrinus by polymerase chain reaction (PCR) amplification, and to relate their presence to the incidence of dental caries in 42 Brazilian preschool children. Dental plaque samples were collected from the cervical margin of all erupted teeth of 5-6 years old children with primary dentition, using a sterile explorer. Examination of the dmft (decayed, missing, filled teeth) index, performed following the World Health Organization (WHO) caries diagnostic criteria, showed a 2.71 score. Prevalence of S. mutans and S. sobrinus was respectively, of 85.7% and 14.3%; no dental plaque sample was either positive or negative for both bacterial species. Children harboring either S. mutans or S. sobrinus presented the same caries prevalence. PCR showed good discriminative ability for differentiation between these species, and suggested that it is a technique suitable for epidemiological studies on mutans streptococci. (+info)
Assessment in vitro of brushing on dental surface roughness alteration by laser interferometry.
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Noncarious cervical lesions (NCCLs) are considered to be of multifactorial origin, normally associated with inadequate brushing. This study assessed the influence in vitro of simulated brushing on NCCL formation. Fifteen human premolars were submitted to brushing in the cementoenamel junction region, using hard-, medium- and soft-bristled brushes associated with a toothpaste of medium abrasiveness under a 200 g load, at a speed of 356 rpm for 100 minutes. The surface topography of the region was analyzed before and after brushing, by means of a laser interferometer, using "cut-off" values of 0.25 and considering roughness values in mm. The initial roughness (mm) results for dentin (D / bristle consistency: 1--soft, 2--medium and 3--hard) were as follows: (D1) 1.25 +/- 0.45; (D2) 1.12 +/- 0.44; (D3) 1.05 +/- 0.41. For enamel (E / bristle consistency: 1--soft, 2--medium and 3--hard), the initial results were: (E1) 1.18 +/- 0.35; (E2) 1.32 +/- 0.25; (E3) 1.50 +/- 0.38. After brushing, the following were the values for dentin: (D1) 2.32 +/- 1.99; (D2) 3.30 +/- 0.96; (D3) Over 500. For enamel, the values after brushing were: (E1) 1.37 +/- 0.31; (E2) 2.15 +/- 0.90; (E3) 1.22 +/- 0.47. Based on the results of the ANOVA and Tukey statistical analyses (a = .05) it was concluded that soft, medium and hard brushes are not capable of abrading enamel, whereas dentin showed changes in surface roughness by the action of medium- and hard-bristled brushes. (+info)
Evaluation of the pulp chamber size of human maxillary first molars: an institution based in vitro study.
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The aim of this in vitro study was to determine the morphological measurements of the pulp chamber and also to establish the relationship of the cemento-enamel junction (CEJ) to the roof of the pulp chamber of the maxillary first molars in an Indian population. One hundred extracted human maxillary first molars were used. Each molar tooth was radiographed by radio visiography (RVG). Measurements were made by using the grid option in RVG. The results (mean +/- SD; in mm) were as follows: distance from floor of the pulp chamber to the furcation = 2.7 +/- 0.63; distance from roof of the pulp chamber to the furcation = 5.34 +/- 0.9; distance from tip of the palatal cusp to the furcation = 11.58 +/- 1.01; distance from the tip of the palatal cusp to the floor of the pulp chamber = 8.86 +/- 0.68; distance from the tip of the palatal cusp to the roof of the pulp chamber = 6.2 +/- 0.66; height of the pulp chamber = 2.62 +/- 0.61. The results of these measurements revealed that the morphological measurements of the maxillary first molars in the Indian population were similar to that reported by previous studies; the roof of the pulp chamber was found at the CEJ in 96% of the specimens. (+info)
The large functional spectrum of the heparin-binding cytokines MK and HB-GAM in continuously growing organs: the rodent incisor as a model.
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Scanning electron microscopic study of dentinal pulpal walls in relation to age and tooth area.
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A study was conducted to observe the surface morphological changes of human dentinal pulpal walls in specific areas of the tooth at various ages. Thirty-two extracted human non-carious teeth with single root canals were used. The teeth were divided longitudinally in the bucco-lingual plane and prepared for scanning electron microscopy (SEM). The specimens were divided into two groups (younger and older) according to age. Four central sites of the dentinal pulpal wall, including coronal, cervical, mid-root and apical sections, were selected as specific locations. Under the conditions of this study, six basic types of SEM appearance at dentinal pulpal wall surfaces were identified on the basis of calcospherite shape and mineralization. The appearance of the calcospherites varied according to tooth age and location along the dentinal pulpal walls. (+info)