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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 purpose of this study was to see if the root surface topography of teeth, stored in saline and subsequently treated with citric acid, differred from the root surface topography of teeth that were treated immediately upon extraction, 12 freshly extracted adult human permanent teeth, with proximal surfaces free of caries and periodontal disease, were treated in succession. The crowns were removed at the level of periodontal attachment, the teeth sectioned buccal-lingually and a treatment area deligniated on each proximal section. The treatment area of 6 teeth was root planed to expose dentin (D) and scaled to remove adherent tissue and leave a cementum surfaces (C) on the other 6 teeth. A coronal-apical groove down the middle of the treatment area divided it into approximately equal parts or experimental regions. One proximal section of each tooth was placed in physiologic saline (S) and treated after 6 weeks of storage while the other proximal section was freshly treated (F). Treatment consisted of applying a 30% citric acid (CA) solution (pH = 1.60) for 5 min. Cotton pellets soaked in the citric acid solution were placed (P) on one half of the experimental area and heavily burnished (B) on the other half. Treatment areas were subsequently prepared for scanning electron microscopy analysis. Assessment was made of (i) the % of surface area tufted, (ii) fibril tufting depth (0.3) and (iii) fibril tufting density (1.3). Similarities were found in the data for both storage methods (F and S) across each application technique (P or B) and each tooth surface (D or C) with respect to the (i) % area tufted and (ii) frequency distribution of tufting depth scores. As for the application techniques, the data for burnishing was greater than placed across each storage method (F or S) and each tooth surface (D or C) for the same two parameters. The results of the study indicated that 6-week physiologic saline storage does not affect root surface demineralization by citric acid, as assessed by SEM.

Better understanding of the furcation anatomy may serve to decrease the risk of pulpal injury during rotary odontoplasty, a procedure often used in conjunction with guided tissue regeneration. The purpose of this study was to determine (i) the tooth thickness about the furcation entrance of lower molars, and (ii) whether there is a relationship between tooth thickness and patient age. 40 mandibular 1st molars (M1) (mean age = 36.2; range 10-65 years) and 40 mandibular 2nd molars (M2) (mean age = 37.9; range 14-70 years) were collected. Age, gender and furcation involvement (if any) were noted for each tooth at the time of extraction. Teeth were sectioned in half, buccal-lingual, at the furcation entrance with a rotary diamond blade. A standardized linear reference scale was placed on each experimental section and an 8 x 10 in. photograph generated. The distance from the floor of the pulp chamber to 5 predetermined sites on the root surface was calculated. The data were expressed as (a) the mean of each site and (b) the mean of each tooth (the average of the 5 points of each tooth). Analysis of covariance failed to show a relationship between thickness measurements and gender or furcation involvement. Thus, the data was subjected to simple regression analysis to determine the relationship of age with tooth and cementum thickness. This study revealed that by site, the mean measurements ranged from 2.7-3.0 mm for both M1 and M2. The single least/greatest measurements of the 5 sites were for M1: 1.6/4.7 mm and for M2: 1.8/4.2 mm. By tooth, the average distance from the pulp to the root surface was 2.83 mm (+/- 0.49) for M1 and 2.88 mm (+/- 0.44) for M2. Regression analysis of tooth thickness with age was significant for M1 only. The maximum slope of the 5 sites was approximately 0.3 mm/10 years. No relationship was found between cementum thickness and age for either tooth group. The results of this study indicate that the majority of times the pulp is 1.6-4.2 mm from the root surface in the vicinity of the furcation entrance of lower 1st and 2nd molars. Although tooth thickness in this area may increase with age, the amount is not enough to forego judicious odontoplasty on older patients.

The purpose of this study was to document and characterize epithelial remnants (EPRs) of the crestal periodontium of the deciduous dentition of a diphyodont and compare them with EPR units found in the corresponding area of the permanent dentition. 7 beagle dogs were used. At the age of 10 weeks (deciduous dentition) and 15 months (permanent dentition), respectively, a 6-week plaque control period was initiated. At the end of each plaque control period, biopsies were obtained from the mandibular 02P, 03P (deciduous dentition) and P3, P4 (permanent dentition) premolar regions and prepared for histologic analysis. 2 regions, (1) the supracrestal region and (2) the periodontal ligament region, were identified. The supracrestal region was divided into 4 compartments of equal height. The histologic parameters studied included the (i) EPR frequency: number of EPRs/mm of root length, (ii) EPR size, (iii) EPR-root distance, (iv) EPR-bone distance and (v) cell area. No differences were observed between the 2 dentitions with respect to the number, size and relative location of EPR units in the supracrestal regions or the periodontal ligament regions. Epithelial remnants of the supracrestal region in both dentitions tended to be more frequent, larger and positioned further from the root surface than the EPRs of the periodontal ligament region. EPR units of the periodontal ligament region were located significantly further from the bone in the deciduous dentition than in the permanent dentition. The cell area of EPRs did not differ between the 2 dentitions. It was concluded that EPRs are a normal component of the crestal periodontal tissues of the deciduous dentitions of the diphyodont beagle dog and they appear to be similar to those found in the permanent dentition of young dogs.

Previous work has shown that a 25-30% citric acid solution was the most effective concentration with which to demineralize dentin. The purpose of this investigation was to study the topography, using a scanning electron microscope, of root surfaces treated with a 30% citric acid solution using various application pressures. 20 freshly extracted human teeth were collected and stored in physiologic saline at room temperature. 3 root specimens, approximately 3x5x5 mm in size, were prepared from the coronal periodontally healthy area of each tooth. 30 specimens were root planed to expose dentin (dentin group) while the remaining 30 specimens were lightly scaled to remove periodontal soft tissue (cementum group). A freshly made 30% citric acid (CA) solution, (pH = 1.60), was applied to each of the experimental areas. Cotton pellets soaked in the citric acid solution were either placed (CAP), lightly rubbed (CAR) or heavily burnished (CAB) on the prepared root surface for 3 min. Pellets were resoaked every 30 s. The root sections were rinsed, fixed in glutaraldehyde, dehydrated in graded ethanol, critically point dried in liquid CO2 and sputter coated in gold. The treated surfaces were assessed for fibril tufting using scanning electron microscopy. Assessment was made of: (i) the % of surface area tufted; (ii) tufting depth (0-3); (iii) tufting density (1-3). Results of the study showed significantly more tufted surface area and greater tufting depth on both dentin and cementum for CAR and CAB compared to CAP. CAP produced a flat/mat fibril surface with no evidence of tufting.(ABSTRACT TRUNCATED AT 250 WORDS)

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)

Maxillary anterior fixed prostheses may be compromised when pontics are adapted to deficient residual alveolar ridges. This study determined the effect of ridge contour on esthetics and function. Thirteen men and 17 women, 23 to 75 years of age, who had received maxillary anterior fixed prostheses during the period 1976 to 1986 participated. A six-item structured interview was conducted for each subject to determine causes of satisfaction or dissatisfaction with esthetics and function. Pontic esthetics were also determined by examination using a 12-point esthetic index that was developed and pretested for this study. Residual ridge contour was classified according to Siebert as being deficient buccolingually (I), deficient apicocoronally (II), or deficient in both areas in combination (III). The results showed that patients with class I ridges had a higher subjective level of satisfaction with their prosthesis than did those with class II or III ridges. Esthetic index scores were significantly higher (p less than 0.05) for type I (10) than for type II (7.4) or III (7.3) using a post hoc Scheffé comparison. These results suggest that consideration be given to ridge augmentation prior to construction of maxillary anterior fixed prostheses, particularly when class II or III defects are present.

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)

A digital computer program written by Westinghouse engineers aids the design of new static logic systems for metal mills. The computer program accepts logic equations specifying the functions to be performed. The program generates circuit drawings of logic circuitry plus paper tape for controlling an automatic wiring machine. The automatic wiring machine wires the back panel receptacles for plug-in cards which contain the integrated-circuit AND/NAND logic elements. The design engineer determines functional requirements to be performed by the logic circuits. He expresses these requirements in convenient logic statement form and adds comments on circuit functioning. Logic and comment statements are keypunched for input to the computer. The computer analyzes the equations, converts the functions to AND/ NAND logic circuits and generates the punched-paper tape required by the automatic wiring machine. In addition, the computer generates the circuit diagrams showing the actual AND/NAND circuits with complete (JIC) cross references and comments on circuit functioning. During computer processing diagnostic messages are generated to aid in finding design errors. Only one type of logic board is used in the new static logic system to perform all logic functions. This reduces maintenance to mere board replacement and greatly reduces spare board inventory. Triac outputs are featured in addition to normal contact closure outputs. Traic is a static ac switch which can operate pilot-operated solenoid valves, contactors, indicating lights, and other common ac loads. The logic system combines the advantages of fully wired integrated-circuit logic with the convenience and accuracy of computer aided design.