The purpose of this investigation was to analyze the clinical crown of the 3 tooth groups of the maxillary anterior sextant of the permanent dentition of normal subjects with respect to (i) width, length and the width/length ratios and (ii) determine if there is a correlation between tooth dimensions or tooth group ratios and subject height. Subjects (> or = 20 y.o.) were recruited for this study if (i) the free gingival margin on the facial surface of teeth in the maxillary sextant was positioned apical to the cervical bulge, (ii) there was no evidence of attachment loss; as determined by lack of a detectable CEJ and (iii) the marginal tissue was knife edged in form, firm in consistency and coral pink in color. Teeth were excluded if (i) there was evidence of gingival alteration, i.e., gingival overgrowth/hyperplasia, inflammation, altered passive eruption, attachment loss, gingival recession or history of periodontal surgery, or (ii) there was evidence or history of incisal edge/proximal tooth alteration as in, i.e., restorative intervention, traumatic injury or occlusal wear into dentin. At least 1 suitable tooth from each tooth group of the maxillary anterior dentition had to be present. A maxillary impression was taken and poured in yellow die stone. The widest mesial-distal portion and the longest apical-coronal portion of the test teeth were measured. Gender, ethnicity and subject height (SH) were recorded for each participant. Due to a limited ethnic diversity only data from the Caucasian group were analyzed. The mean coronal tooth width (mm) of males versus females was CI: 8.59 versus 8.06, LI: 6.59 versus 6.13 and CA: 7.64 versus 07.15. The mean coronal tooth length (mm) of males versus females was CI: 10.19 versus 9.39, LI: 8.70 versus 7.79 and CA: 10.06 versus 8.89. All width and length measures were significantly greater for males than for females. The mean coronal tooth width/length ratios for males versus females was CI: 0.85 versus 0.86, LI: 0.76 versus 0.79 and CA: 0.77 versus 0.81. A comparison between genders of the width/length ratios of the CI and LI were found not to differ, however the CA ratio for females was significantly greater than for males. A statistically significant difference was found to exist between the mean (cm) SH for males versus females: 181.2 versus 164.0. A positive correlation (p < or = 0.0001 to 0.0691) was found to exist between tooth group width/height ratios within genders. No significant correlation was found between any of the tooth dimensions or tooth group ratios and SH. The results of this study indicate that within male and female Caucasians, the mean width/length ratio of the maxillary 3 anterior tooth groups is 0.81. As well, within both genders there is a positive correlation between tooth group width/length ratios. The significance of these findings with respect to periodontal mucogingival plastic surgical procedures is discussed.
The present study is an attempt to assess if age-related changes, manifested as loss of probing attachment and alveolar bone, occur in humans. 511 subjects, in ages 20-24, 30-34, 40-44, 50-54 and 60-64 years, were included in the study. All subjects had undergone a comprehensive clinical examination, including recordings of probing pocket depth and probing attachment level. A subsample of subjects was selected, whose periodontal status indicated minimal experience of destructive periodontal disease. In these particular subjects, the height of the alveolar bone was also assessed. The results showed that in the subsample, (i) attachment loss increased with age, but (ii) a high proportion of tooth surfaces remained with no attachment or alveolar bone loss in ages between 20 and 64 years. There are reasons to suggest, therefore, that age-related alterations in the periodontium may not inevitably be manifested as loss of probing attachment or alveolar bone.
The aim of this study was to examine some clinical and structural features of healthy periodontal tissues in young and old beagle dogs. The material consisted of 10 beagle dogs; group I (1-year old) and group II (8-9 years of age). All animals belonged to the same beagle dog colony and had been carefully monitored from birth. A given day was termed day 0 on which the teeth of all 10 dogs were scaled and polished and a 6-week period of enhanced plaque control was initiated. On day 42, clinical examinations were performed and biopsies obtained from the right mandibular 4th (4P) and 3rd (3P) premolar regions. The biopsies were prepared for histometric and morphometric analyses. Clinically, the lower premolars of the old but not the young dogs showed signs of marked wear. In the old dogs, the free gingival unit had a more curved and bulky appearance than in the young animals and in the old dogs, the free gingiva was consistently separated from the attached gingiva by a gingival groove. The histometrical dimensions of the free marginal gingiva and the width of the coronal portion of the periodontal ligament did not differ between the 2 groups of dogs. The apical cells of the junctional epithelium (aJE) in the young dogs were consistently located at the cemento-enamel junction (CEJ), whereas in the old dogs, aJE was consistently located apical to the CEJ.(ABSTRACT TRUNCATED AT 250 WORDS)
The integrity of formalin-fixed periodontally diseased root surfaces was assessed following root planing to dentin and citric acid application. Extracted human teeth (fixed in 10% formalin), with crowns removed, were vertically sectioned in half. A horizontal groove on each proximal surface marked the extent of attachment loss. The diseased root surface was vigorously root planed to expose dentin. Cotton pellets, soaked in a saturated solution of citric acid, were either "placed" (control) or "burnished" (vigorously rubbed using root planing pressure) (experimental) on the prepared root surface for 5 min. Pellets were changed 2 times/min. The teeth were fixed and prepared for scanning electron microscope viewing and photography. A representative print was selected for each specimen. To confirm differences between test and control groups, untrained raters were asked to perform 2 sorting exercises. First, they were asked to sort the representative photographs of each specimen into 2 piles based on surface characteristics. Second, they were asked to choose from pairs of photographs, representing matched specimens, the one photograph which appeared to have the greatest collagen surface area. The surfaces of experimental specimens revealed patent dentinal tubules and an intertubular area with a very distinct "shag carpet" appearance of deeply tufted collagen fibrils. Control samples also exhibited open dentinal tubules, yet the intertubular surface displayed a "matted collagen" surface. Results of the 2 sorting exercises confirm that burnishing of formalin-fixed dentin root surfaces for 5 min with cotton pellets soaked in a saturated solution of citric acid consistently produces a distinct tufted collagen fibril surface.(ABSTRACT TRUNCATED AT 250 WORDS)
Preliminary work has shown that the rate of dentin demineralization increases with increasing concentrations of citric acid. This rate subsequently diminishes at much higher concentrations. The purpose of this study was to more precisely identify the citric acid concentration which produces peak dentin demineralization and to determine if this demineralization process is time dependent. Flat dentin surfaces were prepared on the buccal and lingual sides of 15 bovine molars. 8 depressions were made in each dentin surface using a #8 round bur in a high-speed handpiece with air-water coolant. Various concentrations of citric acid solutions (weight per cent) were prepared, e.g., 0%, 10%, 20%, 25%, 30%, 35%, 40%, 65% and their respective pH's recorded. 3 microliters of each citric acid solution were placed in individual depressions on the dentin surfaces and left undisturbed for 1, 2 or 3 min. Cotton pellets were used to soak up the citric acid solution, along with any dissolved calcium, and were subsequently placed in 10 ml of 18 Me omega water. The parts per million calcium found in each water sample were determined using atomic absorption spectrophotometry. Peak dentin demineralization for 1-, 2- and 3-min application times occurred at 30% (pH = 1.55), 25% (pH = 1.62) and 25% (pH = 1.62) citric acid concentrations/(pH), respectively. Dentin demineralization was found to be time-dependent for all citric acid solution concentrations. The clinical significance of these findings is discussed.
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