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Biomedical subjects

P B Robertson

Publications and source records attributed to P B Robertson.

At least 19 recordsLinked to original sources
PubMed1995

Smokeless tobacco use: how it affects the performance of major league baseball players.

The authors examined the effect of smokeless tobacco use on the athletic performance of major league baseball players during the 1988 season. They evaluated performance records of 158 players on seven major league teams who played or pitched at least 10 games or innings during the 1988 season. ST use, they concluded, is not related to player performance in major league baseball but does place players at significantly increased risk for mucosal lesions and other oral pathology.

Adult↗
PubMed1992

Periodontal disease associated with HIV infection.

Patients with severe immunosuppression as a consequence of infection by human immunodeficiency virus (HIV) are at risk for a number of severe periodontal diseases. HIV-associated gingivitis and HIV-associated periodontitis (HIV-P) are seen exclusively in HIV-infected persons. In some cases HIV-P may extend into adjacent soft tissue and bone, resulting in necrotizing stomatitis of periodontal origin. In addition, acute necrotizing ulcerative gingivitis has also been reported to have an increased prevalence in HIV-infected patients. The clinical and microbiologic features of HIV-associated gingivitis and HIV-P suggest that these diseases are early and later stages of the same lesion, that results in severe gingival erythema, extensive soft tissue necrosis, and destruction of alveolar bone. Although acute necrotizing gingivitis and the initial stages of HIV-P share a number of clinical signs current evidence indicates that they are distinct pathologic processes. Treatment of these lesions requires debridement, local antimicrobial therapy, immediate follow-up care, and long-term maintenance. In addition, patients with systemic involvement or extensive and rapidly progressing lesions may require systemic antibiotics appropriate to the organisms that dominate the lesion.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Effect of free gingival grafts on naturally-occurring recession in miniature swine.

Miniature swine exhibit naturally-occurring, progressive recession on facial surfaces of the permanent mandibular incisors. The purpose of this study was to determine whether placing a free gingival graft to augment the width of keratinized gingiva of mandibular incisors in miniature swine would prevent or retard recession at the grafted site compared to an untreated contralateral control site. In 8 litter-mate miniature swine, free gingival grafts were placed on the facial surface of the permanent central and lateral incisors on one side of the mandible. The contralateral mandibular incisors did not receive any treatment and served as controls. Clinical measurements, including eruption, recession, pocket depth, attachment level, and keratinized gingival width were obtained preoperatively, 2 to 3 weeks after surgery to assess the success of gingival augmentation, and 3, 6, and 9 months postoperatively. Eight grafted sites were successful and showed significant augmentation of the keratinized gingival width, with a mean increase of 5.8 +/- 0.7 mm, while 6 grafts failed and showed a slight decrease in the mean width of -0.4 +/- 0.5 from the preoperative to postoperative examination. All sites showed significant recession during the experimental period. Successful sites showed no statistically significant or clinically major difference in the rate or amount of recession than contralateral control sites. By 9 months, the average increase in recession from the baseline examination was 2.8 +/- 1.5 mm for successfully grafted sites and 2.6 +/- 1.3 mm for contralateral controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Effects of ascorbic acid depletion and supplementation on periodontal health and subgingival microflora in humans.

This study describes the relationship between varying ascorbate intake, periodontal status, and subgingival microflora as part of a multidisciplinary investigation of ascorbic acid (AA) metabolism in young men housed for 13 weeks in a nutrition suite that provided controlled periods of ascorbic acid depletion and repletion. Twelve medically healthy non-smoking men, aged 25 to 43 years, ate a rotating four-day diet adequate in all nutrients except ascorbic acid. Following an initial baseline period during which the subjects received 250 mg AA/day, the subjects received 5 mg AA/day for a 32-day depletion period. Eight of the 12 subjects participated in a subsequent 56-day repletion period designed to replace the reduced body AA pool slowly. Plasma and leukocyte ascorbate levels, Plaque Index, Gingival Index, probing depths, and attachment level were monitored at the beginning and end of the depletion and repletion periods. Subgingival plaque samples were obtained and examined for selected organisms by indirect immunofluorescence microscopy. A uniform oral hygiene program was reinforced after each examination. Ascorbate concentrations in plasma and leukocytes responded rapidly to changes in vitamin C intake. There were no significant changes in plaque accumulation, probing pocket depth, or attachment level during the study. In contrast, gingival bleeding increased significantly after the period of AA depletion and returned to baseline values after the period of AA repletion. However, no relationship could be demonstrated between either the presence or proportion of target periodontal micro-organisms and measures of bleeding or ascorbate levels.

Actinomyces viscosus↗
PubMed1990

Oral mucosal lesions found in smokeless tobacco users.

The risk for oral mucosal lesions associated with use of smokeless tobacco among 1,109 professional baseball players during spring training in 1988 was investigated. Leukoplakia was very strongly associated with use of smokeless tobacco in this population of healthy young men. Of the 423 current smokeless tobacco users, 196 had leukoplakia compared to seven of the 493 nonusers (OR = 60.0, 95% CI = 40.5-88.8). The amount of smokeless tobacco used (in hours per day that smokeless tobacco was held in the mouth), recency of smokeless tobacco use (hours since last use), type (snuff versus chewing tobacco), and brand of snuff used were significantly associated with risk for leukoplakic lesions among smokeless tobacco users. Ninety-eight leukoplakic areas in 92 subjects were biopsied and examined microscopically. All lesions were benign, but one specimen had mild epithelial dysplasia. The long-term significance of leukoplakia in smokeless tobacco users and their relation to oral cancer is not clear.

Adult↗
PubMed1990

Periodontal effects associated with the use of smokeless tobacco.

This report describes periodontal findings from a comprehensive study of smokeless tobacco use in professional baseball players. Subjects consisted of 1,094 players, coaches, and training staff of seven major league and their associated minor league teams. Before being examined, subjects completed questionnaires on patterns of smokeless tobacco use (validated by blood chemistry studies), rinsed their mouths under supervision, and were cautioned not to discuss their use of tobacco with the dental examiners. They then received a complete oral examination that included recording of all mucosal abnormalities, missing teeth, caries, extrinsic stain, attrition, Plaque Index, Gingival Index, pocket depth, attachment loss, and gingival recession. More than 50% of team members reported using smokeless tobacco, and 39% reported use during the current week. Among current week users, 46% had oral mucosal lesions, located primarily in the mandible at sites where the smokeless tobacco quid was placed. The use of smokeless tobacco was not necessarily associated with severe forms of periodontal disease, and the presence of poor oral hygiene and gingivitis in these users was not related to the development of oral lesions. However, sites adjacent to mucosal lesions in smokeless tobacco users showed significantly greater recession and attachment loss than in sites not adjacent to lesions in users or comparable sites in non-users.

Adult↗
PubMed1989

Effect of rotary electric toothbrush versus manual toothbrush on periodontal status during orthodontic treatment.

Adolescents with fixed orthodontic appliances frequently have increased levels of plaque accumulation and gingivitis. The purpose of this study was to determine whether a rotary electric toothbrush would be more effective than conventional toothbrushing in maintaining periodontal health in these patients. Forty adolescent patients were divided into equal groups matched for sex and age. Before and during placement of orthodontic appliances, one group was instructed in use of the rotary electric toothbrush and the other in the use of a conventional toothbrush; these instructions were reinforced at monthly visits thereafter. Baseline clinical assessments of Plaque Index, Gingival Index, and bleeding tendency were made on six standard teeth before appliances were placed. assessments were repeated at 1, 3, 6, 9, 12, and 18 months after appliances were placed. Intragroup and intergroup differences were tested by a two-way analysis of variance. At baseline there were no significant differences between the two groups for any study variable. During the 18-month study period, however, plaque accumulation and gingivitis increased significantly over baseline levels in the control group (p less than 0.01) but remained stable in the group using the rotary electric toothbrush. In addition, the control group showed significantly greater plaque (p less than 0.01), gingival inflammation (p less than 0.001), and gingival bleeding on probing (p less than 0.001) than did the treatment group from the 1- to 18-month examinations. These data suggest that the rotary electric toothbrush is more effective than conventional toothbrushes for removing plaque and controlling gingivitis in adolescents during orthodontic treatment with fixed appliances.

Child↗
PubMed1989

Comparison of manual and power toothbrushing, with and without adjunctive oral irrigation, for controlling plaque and gingivitis.

We compared the effects of four oral hygiene methods (manual tooth-brushing, power toothbrushing, manual toothbrushing plus irrigation, and power toothbrushing plus irrigation) on plaque and periodontal disease. These methods were tested both when used alone and when used in conjunction with professional mechanical oral hygiene. 108 subjects were clinically assessed for plaque, stain, gingival inflammation, bleeding to probing, probing depth and attachment loss, and randomly assigned to one of the 4 oral hygiene groups. Subjects were carefully instructed in the use of their assigned method and asked to discontinue all other forms of oral hygiene. After 3-months, subjects returned for re-examination and full-month professional mechanical oral hygiene care. 3 months later, subjects returned for a final oral examination. All subjects kept a diary of use of their assigned method and were called every 2 weeks to monitor discomfort, provide reinforcement and answer questions. Results showed that all the oral hygiene methods were equally effective in reducing plaque and stain accumulation, gingival bleeding, bleeding to probing ratio and the % of pockets 4 mm or deeper. None of the oral hygiene methods was associated with injury to soft or hard tissues.

Adolescent↗
PubMed1989

Effect on periodontal status of rotary electric toothbrushes vs. manual toothbrushes during periodontal maintenance. I. Clinical results.

The purpose of this study was to compare the Rotadent rotary electric toothbrush with conventional toothbrushing for its effectiveness in controlling supragingival plaque and gingival inflammation in periodontal maintenance patients. Forty subjects who had received periodontal treatment, including periodontal surgery, for moderate to advanced periodontitis and were on a 3-month periodontal maintenance were divided into two equal groups matched for age and sex. One group used conventional toothbrushing, dental floss, and toothpicks and the other used only the rotary electric toothbrush for a 12-month study period. Single-blind clinical assessments (Plaque Index, Gingival Index, bleeding tendency, pocket depth, and loss of attachment) were made at baseline and at 3, 6, 9, and 12 months after baseline. Subgingival debridement was performed 1 week after the baseline assessment and the 6- and 12-month examinations. Plaque removal was reinforced at 3-month intervals. Both groups had significantly improved scores (P less than 0.01) for Gingival Index and bleeding tendency during the 12-month period, but no differences were found between the groups at any examination. These results indicate that the rotary electric toothbrush is as effective for plaque removal and control of gingival inflammation as a combination of conventional toothbrushing, flossing, and toothpicks for patients in periodontal maintenance.

Adult↗
PubMed1989

Effect of periodontal status of rotary electric toothbrushes vs. manual toothbrushes during periodontal maintenance. II. Microbiological results.

We compared the use of a rotary electric toothbrush with conventional toothbrushing for their effectiveness in modulating the subgingival microbiota. Forty subjects who had received periodontal treatment for moderate to advanced periodontitis and were on 3-month periodontal maintenance were divided into two equal groups matched for age and sex. One group used only the rotary tooth cleaner and the other group used conventional toothbrushing, dental floss, and toothpicks for 12 months. Subgingival plaque samples (two sites per patient) were taken from 10 subjects per group at baseline, 6 months, and 12 months and analyzed for percentage of obligate anaerobes and colony-forming units of black-pigmented Bacteroides, Fusobacterium, Actinomyces, Streptococcus, and Veillonella spp. The percentage of spirochetes and motile rods was determined by darkfield microscopy. Results showed that levels of obligate anaerobes, Fusobacterium, and Actinomyces and percentage of spirochetes and motile rods decreased significantly (P less than 0.05), while levels of Streptococcus spp. increased (P less than 0.05) for both groups. However, there was no significant difference between the two groups, indicating that the rotary tooth cleaner and conventional toothbrushing are equally effective in controlling gingivitis and fostering a less pathogenic microflora.

Adult↗
PubMed1988

Hazards of occupational transmission and strategies for prevention of infectious disease in dental education.

The emergence of AIDS has alerted the nation's health care community to the dangers of occupational transmission of infectious disease. This article assesses the risk of occupational transmission in the health care setting and examines two prevention strategies: vaccination programs and infection control protocols. The implementation of these strategies by the School of Dentistry, University of California at San Francisco, is recounted to illustrate an institutional response to the issue of infection control in the dental setting.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Radiographic detection of dental calculus.

To determine the sensitivity and specificity of the radiographic detection of calculus, 275 proximal tooth surfaces from 18 patients were evaluated. Standardized periapical radiographs obtained before extraction were coded, batch processed, and evaluated independently by two investigators under optimum viewing conditions. After extraction, the teeth were photographed and evaluated both microscopically and by planimetry on 40 X linear projections. Evaluation of calculus by conventional radiography showed low sensitivity: radiographic deposits were detected on only 44% of surfaces that demonstrated calculus microscopically. Specificity was high and the rate of false positives was only 7.5%. Detection of calculus was influenced by the thickness of calculus, the percentage of root surface occupied by calculus, and by tooth type; but not by attachment loss, probing depth, proximal surface, or arch location. These results show that present radiographic techniques are not appropriate for detecting calculus on root surfaces.

Adult↗
PubMed1987

Calculus removal by scaling/root planing with and without surgical access.

We assessed the presence and extent of calculus on subgingival root surfaces of teeth that received scaling and root planing (S/RP) alone, S/RP with modified Widman flap, or no treatment. After extraction, each surface was examined to determine the pocket depth (PD), area of root surface exposed to the pocket (A), and amount of pocket area showing retained calculus (C). Calculus-positive teeth (CPT) and surfaces (CPS) and percentage of pocket area occupied by calculus (C/A) were derived for each group. In general, CPT and CPS were significantly lower after S/RP with flap (37% and 14%, respectively) than after S/RP alone (62% and 24%). The advantage of S/RP with flap was greatest for facial and lingual surfaces and for anterior and premolar teeth. In both treatment groups CPS were similar over a pocket depth range of 0 to 6 mm. But in deeper pockets, CPS in teeth treated by S/RP with flap remained constant at 17% while after S/RP alone CPS increased linearly to approximately 45% at greater than 8 mm. The mean C/A was essentially equal in both treatment groups (11%) and was not related to pocket depth.

Adult↗
PubMed1986

Clinical and microbiologic effects of single-dose metronidazole or scaling and root planing in treatment of adult periodontitis.

Sites affected with adult periodontitis were observed for 3 months to compare their clinical and microbiologic responses to a single 2 g dose of metronidazole, scaling and root planing, or no treatment. 2 sites with probing depths greater than or equal to 5 mm in each of 18 female subjects (6 in each treatment group) were evaluated clinically (plaque and bleeding indices, probing depth, attachment loss) and microbiologically (%s of cocci, motile rods, non-motile rods and spirochetes, and of obligate anaerobic colony-forming units, black-pigmented Bacteroides, Fusobacterium and Actinobacillus actinomycetemcomitans in subgingival plaque). No significant differences in these variables existed between the 3 groups at baseline. The no-treatment (control) group showed no substantial clinical or microbiologic changes during the study. After 1 month, scaling and root planing had effected significant clinical improvement and significant shifts in the subgingival flora to a pattern more consistent with periodontal health; these changes were still evident at 3 months. In contrast, 1 month after metronidazole, there was some clinical improvement and a significant increase in cocci and a decrease in motile rods, but at 3 months these changes were no longer evident. The results show that the benefits of scaling and root planing are sustained for at least 3 months. However, the benefits of a single 2 g dose of metronidazole are both few and transient, indicating that this regimen, while effective against anaerobic infections in other organ systems, is not clinically or microbiologically effective in the treatment of adult periodontitis.

Adult↗