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PubMed1994

Tooth lead levels and IQ in school-age children: the Port Pirie Cohort Study.

The relation between lead concentration in deciduous central upper incisor teeth and intellectual functioning was examined in 262 children who were followed from birth to age 7 years in the lead smelter town of Port Pirie, South Australia, and its environs. Intellectual functioning of the children was assessed over the 3-year period from 1986 to 1989 with the revised Wechsler Intelligence Scale for Children (WISC-R) while each child was in his or her eighth year. There was an inverse relation between tooth lead concentration and intellectual development; the intelligence quotient declined by 2.6 points (90% confidence interval (CI) 0.13-4.9) for each natural-log unit increase in tooth lead concentration, expressed in parts per million. Some WISC-R subscales were more strongly associated with lead exposure than others. In particular, tooth lead was significantly negatively associated with scores for the "Block Design" test (partial regression coefficient -1.25 points per unit of natural-log tooth lead; 90% CI -0.61 to -1.89). No statistically significant interaction between a child's sex and tooth lead concentration was found for any of the WISC-R scales. These findings are in agreement with previously published results from this cohort for which serial blood lead concentrations were used to estimate lifetime lead burden.

Child↗

PubMed2002

Virtual endodontics: three-dimensional tooth volume representations and their pulp cavity access.

The purpose of this study was the application of both digital three-dimensional image processing and virtual reality techniques in endodontics. Three-dimensional volume representations of 2 teeth from each tooth category, 16 teeth in total, have been reconstructed. All teeth were embedded in polyester resin, and serial cross-sections 0.75-mm thick were taken from each tooth by using a special microtome. Each section was studied under a stereoscopic microscope, and its microscopic image was directly digitized using a video-camera. The surfaces of hard dental tissues were segmented from each section. Semiautomatic alignment and frame interpolation were performed on the sequence of tooth sections by using appropriate digital image processing techniques. Three-dimensional volume representations from each tooth were achieved in this project to produce the final three-dimensional teeth models, on which virtual accesses of pulp cavities have been performed. Three-dimensional teeth volume representations and virtual tooth "drilling" could serve as perfect educational tools under certain circumstances.

Anatomy, Cross-Sectional↗

PubMed1980

Serum and cell-mediated cytotoxicity after primary and secondary orthotopic tooth transplants among RhLA-paired rhesus monkeys.

Twenty-six rhesus monkeys were paired on the basis of RhLA serologically defined (SD) antigens and then mixed lymphocyte cultures (MLCs) were performed for each donor-recipient combination. All but one monkey responded positively to its partner in MLC. In vitro assays for complement-dependent antibody-mediated cytotoxicity (CDC) and lymphocyte-mediated cytotoxicity (LMC) were performed before and after each of two separate orthotopic tooth transplants for each recipient. There was no detectable CDC or LMC before tooth transplantation. The maxillary right central incisors were exchanged between paired monkeys and 60 days later the left maxillary central incisors were transplanted. After the first tooth allograft, there was very little CDC activity in any recipient and only one matched group showed any remarkable LMC activity. However, after the second tooth transplant there was a very clear CDC response in the majority of monkeys. The LMC activity remained low after retransplantation. There did not seem to be any consistent relationship between RhLA match and in vitro cytotoxicity. The results indicate that tooth allografts are weak immunogens but they do evoke humoral immunity after retransplantation. The biological relevance of these serum antibodies remains to be determined.

Animals↗

PubMedDate not supplied

Effect of estrogen use on tooth retention, oral bone height, and oral bone porosity in Japanese postmenopausal women.

OBJECTIVE: Recent studies in the United States support the protective effect of estrogen use on tooth retention; however, little is known as to how estrogen promotes tooth retention. The aims of this study were to investigate the effects of estrogen use on tooth retention, oral bone height, and oral bone porosity in Japanese postmenopausal women and to clarify how estrogen promotes tooth retention. DESIGN: Relationships among the number of teeth remaining (total, anterior, and posterior teeth), oral bone height, oral bone porosity, bone mineral density of the lumbar spine and the femoral neck, estrogen use status, and the duration of estrogen use were evaluated in 330 Japanese postmenopausal women (mean age +/- SD, 56.8 +/- 7.6 y). RESULTS: Analysis of covariance adjusted for confounding variables revealed that estrogen users (66 women) tended to have more posterior teeth than did nonusers (264 women) (P = 0.065), although there were no significant differences in number of total (P = 0.196) and anterior (P = 0.751) teeth remaining, oral bone height (P = 0.970), oral bone porosity (P = 0.745), and bone mineral density of the lumbar spine (P = 0.459) and the femoral neck (P = 0.749) between estrogen users and nonusers. Multiple regression analysis showed that the duration of estrogen use was significantly associated with number of total (P = 0.019) and posterior (P = 0.007) teeth remaining, independent of age and oral bone height. CONCLUSION: Our results suggest that estrogen may promote tooth retention by strengthening the periodontal attachment surrounding the teeth, but not increasing oral bone height and not decreasing oral bone porosity.

Absorptiometry, Photon↗

PubMed2003

Racial variations in dental procedures: the case of root canal therapy versus tooth extraction.

BACKGROUND: Racial disparities have been widely documented in medical care, but variations in dental care have not been well examined. OBJECTIVES: To determine if there is racial variation in use of root canal therapy versus tooth extraction across different levels of dental insurance coverage and adjusting for other factors known to influence treatment decisions. METHODS: Within 3 different categories of insurance coverage, we examined whether there were racial differences in the provision of the tooth-sparing treatment of root canal therapy (vs. tooth extraction) among 54,423 users of outpatient Veterans Affairs dental care in 1998. Regression analyses adjusted for the severity of tooth- and gum-related disease, age, sex, medical and psychiatric comorbidities, prior use of preventive dental services, tooth extraction and root canal therapy, and clustering by geographic region. RESULTS: In the adjusted regression models, black patients and those with unknown race were less likely overall to receive root canal therapy than whites, whereas Asians were more likely. Among patients with eligibility for continuing and comprehensive dental care, blacks were less likely and Asians more likely to receive root canals than whites. For patients covered only for emergency dental care, Hispanics had a higher likelihood of receiving root canal therapy. Among all other types of coverage, there were no significant racial differences in the care received. CONCLUSION: We observed substantial racial variations in the provision of root canal therapy among patients treated in Department of Veterans Affairs dental clinics. Future research should identify the causes of such variations.

Black or African American↗

PubMed2001

Development of a magnetic sensing device for tooth displacement under orthodontic forces.

We have developed a system for measuring tooth displacement from orthodontic force. Eight small magnetic sensors and a magnet are combined to measure three-dimensional displacement. Sensors, arranged cubically in the three planes of space, are placed in the mouth and fixed to the posterior teeth by a splint. A magnet is placed in the center of the eight sensors and attached to a front tooth that is subjected to orthodontic force. Sensors detect the magnet's movement as target tooth displacement. The system was designed to achieve displacement resolution of 1 microm. The mean percentage of measurement errors was determined to be less than 1% in a 600-cubic-microm volume from calibration. The system was tested clinically on human teeth. Although the oral environment, with high temperature and humidity, was not agreeable with the sensors, this system was stable and accurate enough for quantitative measurement of tooth displacement. The advantage of this system is the ability to detect tooth trajectories by decomposing displacement into translation and rotation and to determine the position of the center of rotation from these parameters.

Calibration↗

PubMed1977

Kinematics of the tooth tapping movement.

Electrical activity in the masseter muscles and tooth contact vibrations were recorded simultaneously from subjects tapping their teeth slowly into maximal intercuspidation and again with maximal frequency. High speed cinephotography was also used with four of the ten subjects. Three main parts could be distinguished on the obtained graphical representation of the tooth tapping movement: tooth contact phase (TCP), opening phase (OP) and closing phase (CP). Tapping frequency was increased by decreasing the jaw opening degree and the durations of TCP, OP and CP. The jaw velocity immediately before tooth contact, which may be of significance for the reflex response, was however not increased. The average jaw speed was nevertheless increased from 10 to 15 cm/s since the turning from OP to CP was more abrupt in high than in low frequency tapping. The duration of electrical activity after tooth contact was significantly shorter at tapping with high than with low frequency. The teeth maintained contact without detectable rebound between each open-close cycle. The OP started about 100 ms after the cessation of electrical activity both at low and high tapping frequency. The time between end of electrical activity and the start of a new OP was supposed to be dependent upon the relaxation time of the masseter muscles.

Adult↗

PubMed1986

The effect of partial denture design on abutment tooth and saddle movement.

A laboratory investigation designed to simulate the effect of loads applied to a free-end saddle partial denture was carried out. Abutment tooth and also saddle movement were monitored using a photogrammetric method. Loads applied to the denture saddle were transmitted through the occlusal rest and also the clasp components causing movement of both denture saddle and the abutment tooth. The direction of abutment tooth movement was towards the mesial, whether the occlusal rest was situated on the mesial or distal aspect of the tooth crown. It was also evident that the design of the clasp unit used affects the magnitude and direction of abutment tooth movement.

Dental Abutments↗

PubMed1991

Proximal tooth surface quality and periodontal status.

The aim of this study was to determine the periodontal status in relation to the quality of the adjacent proximal tooth surface. The gingival index (GI) and probable pocket depth (PD) were measured in 144 contra-lateral pairs of sound vs. restored and 95 contra-lateral pairs of sound vs. carious surfaces in 124 patients. The restorations studied were silver amalgams and tooth-coloured filling materials, the margins of which were supragingival or level with the gingival margins. The results showed that the GI and PD were greater for both restored and carious tooth surfaces than for the contra-lateral sound surfaces. When all the teeth were grouped together, the differences in the mean values of GI and PD were statistically significant at the P less than or equal to 0.05 level. A comparison between restored and carious (non-paired) tooth surfaces revealed higher mean values of GI and PD for the latter, which were highly significant at the P less than 0.001 level. Thus the present study shows that proximal tooth surface quality influences the health status of the adjacent periodontium.

Adult↗

PubMed1989

Relationship between mutans streptococci in saliva and their colonization of the tooth surfaces.

The relationship between the salivary concentration of mutans streptococci and their prevalence on different tooth surfaces was studied in 114 subjects. Plaque samples were obtained from all tooth surfaces in the dentition and the infection magnitude of mutans streptococci was determined. The salivary concentrations of mutans streptococci correlated significantly with the number of colonized tooth surfaces and with the infection level of mutans streptococci for individual teeth or groups of tooth surfaces. The highest correlation values were found for buccal and approximal surfaces and for molars followed by premolars and anterior teeth. The 10 tooth surfaces best reflecting the salivary levels of mutans streptococci were 5 buccal and 5 approximal sites, 6 of them localized on maxillary posterior teeth. A significant positive relationship was noted between the prevalence of mutans streptococci in saliva and on the dorsum of the tongue.

Adolescent↗

PubMed2005

Evaluation of soft tissue around single-tooth implant crowns: the pink esthetic score.

AIM: In this study, the reproducibility of a newly developed pink esthetic score (PES) for evaluating soft tissue around single-tooth implant crowns was assessed. The effect of observer specialization was another point of interest. MATERIAL AND METHODS: Twenty observers (five prosthodontists, five oral surgeons, five orthodontists and five dental students) were given photographs of 30 single-tooth implant crowns. Seven variables were evaluated vs. a natural reference tooth: mesial papilla, distal papilla, soft-tissue level, soft-tissue contour, alveolar process deficiency, soft-tissue color and texture. Using a 0-1-2 scoring system, 0 being the lowest, 2 being the highest value, the maximum achievable PES was 14. Each observer was requested to make two assessments at an interval of 4 weeks. At the second assessment, the photographs were scored in the reverse order. RESULTS: The mean PES of evaluations at the first assessment (n=600) was 9.46 (+/-3.81 SD), and 9.24 (+/-3.8 SD) at the second one. The difference between these two means was not significant statistically (P=0.6379). Implant-related mean PES for single-tooth implants varied from 2.28 to 13.8, with standard deviations between 0.46 and 3.51. Very poor and very esthetic restorations showed the smallest standard deviations. The mean total PES was 10.6 for the prosthodontists, 9.2 for the oral surgeons, 9.9 for the dental students and 7.6 for the orthodontists. CONCLUSIONS: The PES reproducibly evaluates peri-implant soft tissue around single-tooth implants. Thus, an objective outcome of different surgical or prosthodontic protocols can be assessed. Orthodontists were clearly more critical than the other observers.

Adult↗

PubMed2006

Survival and complication rates of combined tooth-implant-supported fixed partial dentures.

OBJECTIVES: The objective of this study has been to review the incidence of biological and technical complications in case of tooth-implant-supported fixed partial denture (FPD) treatments on the basis of survival data regarding clinical cases. MATERIAL AND METHODS: Based on the treatment documentations of a Bundeswehr dental clinic (Cologne-Wahn German Air Force Garrison), the medical charts of 83 patients with tooth-implant-supported FPDs were completely recorded. The median follow-up time was 4.73 (time range: 2.2-8.3) years. In the process, survival curves according to Kaplan and Meier were applied in addition to frequency counts. RESULTS: A total of 84 tooth-implant (83 patients) connected prostheses were followed (132 abutment teeth, 142 implant abutments (Branemark, Straumann). FPDs: the time-dependent illustration reveals that after 5 years, as many as 10% of the tooth-implant-supported FPDs already had to be subjected to a technical modification (renewal (n=2), reintegration (n=4), veneer fracture (n=5), fracture of frame (n=2)). In contrast to non-rigid connection of teeth and implants, technical modification measures were rarely required in case of tooth-implant-supported FPDs with a rigid connection. There was no statistical difference between technical complications and the used implant system. Abutment teeth and implants: during the observation period, none of the functionally loaded implants (n=142) had to be removed. Three of the overall 132 abutment teeth were lost because of periodontal inflammation. The time-dependent illustration reveals, that after 5 years as many as 8% of the abutment teeth already required corresponding therapeutic measures (periodontal treatment (5%), filling therapy (2.5%), endodontic treatment (0.5%)). After as few as 3 years, the connection related complications of implant abutments (abutment or occlusal screw loosening, loss of cementation) already had to be corrected in approximately 8% of the cases. In the utilization period there was no screw or abutment fracture. CONCLUSION: Technical complications of implant-supported FPDs are dependent on the different bridge configurations. When using rigid functional connections, similarly favourable values will be achieved as in case of solely implant-supported FPDs. In this study other characteristics like different fixation systems (screwed vs. cemented) or various implant systems had no significant effect to the rate of technical complications.

Adult↗

PubMed1980

Interrelationship of inflammation and tooth mobility (trauma) in pathogenesis of periodontal disease.

A series of studies has investigated interactions between periodontal trauma and marginal periodontitis in relation to the initiation, progression and treatment of periodontal disease. Lesions of trauma in the periodontal ligament consequent to either single or jiggling displacing forces result in morphologic alterations in the ligament and alveolar bone. These changes do not initiate the loss of connective tissue attachment characteristic of marginal periodontitis. Studies conducted in squirrel monkeys and beagle dogs in which jiggling forces have been produced subjacent to an established marginal periodontitis reported increased loss of alveolar bone, but the accelerated loss of attachment which occurred in the dog model did not occur in the monkey model. To clarify the relative importance of inflammation and tooth mobility in the treatment of advanced periodontal disease, periodontal response was evaluated after removing traumatic and/or inflammatory components. Elimination of trauma in the presence of existing marginal inflammation did not reduce tooth mobility or increase bone volume. Osseous regeneration and decreased tooth mobility occurred after resolving both components, however, similar findings occurred after resolving inflammation in the presence of continued tooth mobility. Resolution of marginal inflammation is of prime importance in the management of periodontal disease. After resolution of inflammation, bone regeneration may occur around mobile teeth and, furthermore, any residual tooth mobility does not result in increased loss of connective tissue attachment.

Animals↗

PubMed1980

Tooth mobility and periodontal therapy.

Data collected as part of an 8-year longitudinal study on periodontal therapy involving 82 patients and 1974 teeth were analyzed to determine if tooth mobility influenced the result of treatment. For each patient, pocket depth, attachment level and tooth mobility were scored clinically at the initial appointment, and once a year for 8 years following periodontal therapy. The treatment consisted of scaling, oral hygiene instruction, occlusal adjustment, periodontal surgery (curettage, modified Widman or pocket elimination), followed by recall prophylaxes every 3 months. Tooth mobility data on a scale of 0--3 were related to changes in attachment levels for three grades of severity of periodontal disease, based on initial pocket depth (1--3 mm, 4--6 mm, and 7 + mm). Mean patient attachment changes were calculated from teeth in the same severity category for each patient. The data were analyzed by one-way analysis of variance and Scheffe's multiple comparison procedure to test the hypothesis of equal effects of tooth mobility on the results of the treatment for the three severity groups over 8 years. The results indicate that there is a statistically significant relationship between original tooth mobility and the change in level of attachment following treatment. Pockets of clinically mobile teeth do not respond as well to periodontal treatment as do those of firm teeth exhibiting the same initial disease severity.

Humans↗

PubMed1980

Assessment of tooth mobility using small loads. II. Effect of oral hygiene procedures.

Tooth mobility at loads between 20 p and 80 p was studied in maxillary incisors and canines in eight subjects with moderate periodontal disease. The periodontal conditions of the investigated teeth exhibited clinical criteria of gingival inflammation and a moderate loss of attachment. None of the subjects showed subjective or clinical signs of occlusal disturbances. In all, 35 teeth were investigated over the 12-week period following periodontal hygiene treatment, including oral hygiene instructions and removal of supra- and subgingival plaque and calculus. During the course of the investigation, a gradual decrease of tooth mobility was observed amounting to a tooth mobility decrease of 65% (using the corrective formula described by Mühlemann 1960) at 50 p load. Tooth mobility curves within the 20--80 p loading area were transformed to lines of regression (Persson & Svensson 1980). Analyses of the lines showed significantly lower tooth mobility values 12 weeks after start of treatment.

Adult↗

PubMed1982

The effect of single morning and evening rinses of chlorhexidine on the development of tooth staining and plaque accumulation. A blind cross-over trial.

A dietary aetiology for tooth staining associated with the use of chlorhexidine has been postulated. The time related activity of chlorhexidine would therefore suggest that evening rinsing would result in less staining than morning rinsing. This study measured tooth and tongue staining and plaque accumulation in a group of 18 volunteers, rinsing once at night or once in the morning with chlorhexidine in a blind cross-over design. Beverage intake during two 10-day periods was prescribed. Significantly more tooth staining, but not tongue staining, was seen with morning rinsing. Plaque accumulation showed a trend to more plaque with morning rinsing, which was not significant. The findings would be consistent with a dietary aetiology for tooth staining. However, these results emphasise the considerable duration of activity of chlorhexidine on surfaces in the oral cavity and the theory of progressive desorption of chlorhexidine from the tooth surface is questioned.

Adult↗

PubMed2004

The long-term effect of a plaque control program on tooth mortality, caries and periodontal disease in adults. Results after 30 years of maintenance.

BACKGROUND: The biofilm that forms and remains on tooth surfaces is the main etiological factor in caries and periodontal disease. Prevention of caries and periodontal disease must be based on means that counteract this bacterial plaque. OBJECTIVE: To monitor the incidence of tooth loss, caries and attachment loss during a 30-year period in a group of adults who maintained a carefully managed plaque control program. In addition, a comparison was made regarding the oral health status of individuals who, in 1972 and 2002, were 51-65 years old. MATERIAL AND METHODS: In 1971 and 1972, more than 550 subjects were recruited. Three hundred and seventy-five subjects formed a test group and 180 a control group. After 6 years of monitoring, the control group was discontinued but the participants in the test group was maintained in the preventive program and was finally re-examined after 30 years. The following variables were studied at Baseline and after 3, 6, 15 and 30 years: plaque, caries, probing pocket depth, probing attachment level and CPITN. Each patient was given a detailed case presentation and education in self-diagnosis. Once every 2 months during the first 2 years, once every 3-12 months during years 3-30, the participants received, on an individual need basis, additional education in self-diagnosis and self-care focused on proper plaque control measures, including the use of toothbrushes and interdental cleaning devices (brush, dental tape, toothpick). The prophylactic sessions that were handled by a dental hygienist also included (i) plaque disclosure and (ii) professional mechanical tooth cleaning including the use of a fluoride-containing dentifrice/paste. RESULTS: Few teeth were lost during the 30 years of maintenance; 0.4-1.8 in different age cohorts. The main reason for tooth loss was root fracture; only 21 teeth were lost because of progressive periodontitis or caries. The mean number of new caries lesions was 1.2, 1.7 and 2.1 in the three groups. About 80% of the lesions were classified as recurrent caries. Most sites, buccal sites being the exception, exhibited no sign of attachment loss. Further, on approximal surfaces there was some gain of attachment between 1972 and 2002 in all age groups. CONCLUSION: The present study reported on the 30-year outcome of preventive dental treatment in a group of carefully monitored subjects who on a regular basis were encouraged, but also enjoyed and recognized the benefit of, maintaining a high standard of oral hygiene. The incidence of caries and periodontal disease as well as tooth mortality in this subject sample was very small. Since all preventive and treatment efforts during the 30 years were delivered in one private dental office, caution must be exercised when comparisons are made with longitudinal studies that present oral disease data from randomly selected subject samples.

Adult↗

PubMed2005

Implant-supported single-tooth restorations: a 5-year prospective study.

BACKGROUND: Comparatively few studies are available reporting at least 5 years of follow-up data of implant-supported single-tooth replacements. OBJECTIVE: To evaluate prospectively the 5-year outcome of implant-supported single-tooth prosthetic restorations. MATERIAL AND METHODS: Forty subjects (mean age 41 years), 23 males and 17 females, who required single-tooth prosthetic replacement for a missing tooth were recruited. A total of 45 self-tapping implants (Astra Tech ST-implants)--40 in the maxilla and five in the mandible--were installed in a two-stage procedure. Abutment connection was performed 3-6 months after implant installation. Clinical and radiographic examinations were performed at the completion of the prosthetic treatment and once a year during a 5-year follow-up period. The analysis of peri-implant bone level alteration was performed on subject and implant levels and by the use of analysis of variance and binary logistic regression. RESULTS: Three patients were lost during the 5 years of follow-up. One implant was lost after 2.5 years in function and another four implants could not be accounted for at the 5-year follow-up examination. The overall failure rate at 5 years was 2.6% (subject level) and 2.3% (implant level). The mean loss of marginal bone at the implants during the first year in function was 0.06 mm (SD 0.67) on the subject level and 0.02 mm (0.65) on the implant level. During the subsequent 4 years the annual change in peri-implant bone level amounted to -0.02 mm (0.22) on both subject and implant levels. Thus, the mean total bone level change over the 5-year interval was -0.14 mm (1.04) on subject level and -0.11 mm (1.00) on the implant level of analysis (p>0.05). The frequency of implants with a 5-year bone loss of > or =1 mm was 13%. Approximately 50% of the implants demonstrated no bone loss. CONCLUSION: The present clinical trial on single-tooth replacements with the Astra Tech implant system demonstrated that the bone loss during the first year of function as well as annually thereafter was small.

Adult↗