Mm Of Loss Research Articles

Assessment of the Orthodontic External Resorption in Periodontal Breakdown-A Finite Elements Analysis (Part I).

This Finite Elements Analysis (FEA) assessed the accuracy of Tresca failure criteria (maximum shear stress) for the study of external root resorption. Additionally, the tooth absorption-dissipation ability was assessed. Overall, 81 models of the second mandibular premolar, out of a total of 324 simulations, were involved. Five orthodontic movements (intrusion, extrusion, rotation, translation, and tipping) were simulated under 0.6 N and 1.2 N in a horizontal progressive periodontal breakdown simulation of 0-8 mm. In all simulations, Tresca criteria accurately displayed the localized areas of maximum stress prone to external resorption risks, seeming to be adequate for the study of the resorptive process. The localized areas were better displayed in the radicular dentine-cementum component than in the entire tooth structure. The rotation and translation seem prone to a higher risk of external root resorption after 4 mm of loss. The resorptive risks seem to increase along with the progression of periodontal breakdown if the same amount of applied force is guarded. The localized resorption-prone areas follow the progression of bone loss. The two light forces displayed similar extensions of maximum stress areas. The stress displayed in the coronal dentine decreases along with the progression of bone loss. The absorption-dissipation ability of the tooth is about 87.99-97.99% of the stress.

Assessment of Oral Health Status among the Kutia Kandha Tribe - A Particularly Vulnerable Group Residing in Kandhamal District, Odisha

Objective: In Odisha, the Kandha tribal group is numerically the most populous tribe. Among the several sections of the Kandha communities, two sub-sections, the Kutia Kandha and Dongria Kandha, have been identified as Particularly Vulnerable Tribal Groups (PVTGs). As a result, the study’s aim was to assess the oral health status of the Kutia Kandha tribe. Material and Methods: A cross-sectional survey was carried out among 850 Kutia Kandhas using a multistage randomised sampling method in the Tumudibandha Block of Kandhamal District. Data were collected using the World Health Organization (WHO) Oral Health Assessment Form, 2013. Numbers and percentages were analyzed using Microsoft Excel and Statistical Package for the Social Science (SPSS) package version 26.0. Comparisons between discrete and continuous data were done using the Chi-square test and ANOVA. A p-value of 0.05 was considered to be statistically significant. Results: The study population consisted of 850 subjects stratified into seven different age groups. The mean DMFT (permanent) and dmft (deciduous) scores of were 4.06±3.55 and 0.12±0.56 respectively. One hundred fifty-one (16.0%) subjects had bleeding. Three hundred and sixty-two (42.6%) subjects had pockets 4-6 mm and 276 (32.5%) had pockets more than 6 mm. Four hundred and seventy-six (56%) of the study participants had 4-5 mm of loss of attachment followed by 303 (35.6%) with 6-8 mm loss of attachment. Conclusion: The prevalence of caries and periodontal diseases was high. Due to a lack of knowledge about oral hygiene maintenance, proper health education should be provided to the Kutia Kandha tribals.

Assessment of the Maximum Amount of Orthodontic Force for PDL in Intact and Reduced Periodontium (Part I).

This study examines 0.6 N and 1.2 N as the maximum orthodontic force for periodontal ligament (PDL) at multiple levels of periodontal breakdown, and the relationships with the ischemic, necrotic, and resorptive risks. Additionally, this study evaluates if Tresca failure criteria is more adequate for the PDL study. Eighty-one 3D models (from nine patients; nine models/patients) with the 2nd lower premolar and different degrees of bone loss (0-8 mm) where subjected to intrusion, extrusion, rotation, translation, and tipping movements. Tresca shear stress was assessed individually for each movement and bone loss level. Rotation and translation produced the highest PDL stresses, while intrusion and extrusion determined the lowest. Apical and middle third PDL stresses were lower than the cervical stress. In intact periodontium, the amount of shear stress produced by the two investigated forces was lower than the 16 KPa of the maximum physiological hydrostatic pressure (MHP). In reduced periodontium (1-8 mm tissue loss), the apical amount of PDL shear stress was lower than MHP for both applied forces, while cervically for rotation, translation and tipping movements exceeded 16 KPa. Additionally, 1.2 N could be used in intact periodontium (i.e., without risks) and for the reduced periodontium only in the apical and middle third of PDL up to 8 mm of bone loss. However, for avoiding any resorptive risks, in the cervical third of PDL, the rotation, translation, and tipping movements require less than 0.2-0.4 N of force after 4 mm of loss. Tresca seems to be more adequate for the study of PDL than other criteria.

Assessment of the Maximum Amount of Orthodontic Force for Dental Pulp and Apical Neuro-Vascular Bundle in Intact and Reduced Periodontium on Bicuspids (Part II).

This study examines 0.6 N-4.8 N as the maximum orthodontic force to be applied to dental pulp and apical NVB on intact and 1-8 mm reduced periodontal-ligament (PDL), in connection with movement and ischemic, necrotic and resorptive risk. In addition, it examines whether the Tresca finite-element-analysis (FEA) criterion is more adequate for the examination of dental pulp and its apical NVB. Eighty-one (nine patients, with nine models for each patient) anatomically correct models of the periodontium, with the second lower-premolar reconstructed with its apical NVB and dental pulp were assembled, based on X-ray CBCT (cone-beam-computed-tomography) examinations and subjected to 0.6 N, 1.2 N, 2.4 N and 4.8 N of intrusion, extrusion, translation, rotation, and tipping. The Tresca failure criterion was applied, and the shear stress was assessed. Forces of 0.6 N, 1.2 N, and 2.4 N had negligible effects on apical NVB and dental pulp up to 8 mm of periodontal breakdown. A force of 4.8 N was safely applied to apical NVB on the intact periodontium only. Rotation and tipping seemed to be the most invasive movements for the apical NVB. For the dental pulp, only the translation and rotation movements seemed to display a particular risk of ischemia, necrosis, and internal orthodontic-resorption for both coronal (0-8 mm of loss) and radicular pulp (4-8 mm of loss), despite the amount of stress being lower than the MHP. The Tresca failure criterion seems more suitable than other criteria for apical NVB and dental pulp.

Abstract 256: Periodontal disease severity and incident cancer in postmenopausal women: the Buffalo OsteoPerio Study

Abstract Background: Periodontal disease has an infectious etiology and there is growing evidence that it may be positively associated with cancer occurrence. Potential mechanisms may involve the host inflammatory response to oral infection and the potential mobility of the oral microbiome to extra-oral sites. However, few studies have focused on older postmenopausal women who are susceptible to both periodontal disease and cancer and where comprehensive periodontal assessments have been made. This study aims to determine whether loss of alveolar crestal bone height (ACH) in the oral cavity, a measure of chronic periodontitis, is associated with incident cancer in a well-characterized cohort of postmenopausal women. Methods: We prospectively followed a cohort of 1,337 postmenopausal women (aged 53-85 years at baseline; 3% current smokers) who participated in the Buffalo OsteoPerio Study, an ancillary study of the Women's Health Initiative. Whole mouth mean and worst site ACH (mm of loss) were assessed from oral radiographs. Incident cancer was ascertained from annual health updates and confirmed using medical records by physician adjudicators. Cox proportional hazard regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for associations of ACH with total and site-specific cancer risk in multivariate-adjusted models. Results: During an average follow-up of 9.6 years (SD=2.7), there were 170 confirmed incident cancer cases. The most common sites were breast (N=77), lung (N=15), colorectum (N=14), and endometrium (N=12), accounting for 69% of all cancers. When analyzed as a continuous exposure and after adjusting for age, education, and pack-years of smoking, worst site ACH was not associated with total cancer risk (HR=1.04 per 1mm loss, 95% CI=0.94-1.15). However, there was a statistically significant increased risk of lung (HR=1.49, 95% CI=1.18-1.89) and colorectal cancer (HR=1.35, 95% CI=1.04-1.74). No associations were found for worst site ACH with breast (HR=0.91, 95% CI=0.77-1.09) or endometrial cancer (HR=0.77, 95% CI=0.46-1.30). Whole mouth mean ACH was also significantly associated with incident lung cancer (HR=2.05 per 1mm loss, 95% CI=1.40-3.01), but not with total cancer (HR=1.09, 95% CI=0.89-1.33), or with colorectal (HR=1.45, 95% CI=0.91-2.33), breast (HR=0.83, 95% CI=0.57-1.20) or endometrial (HR=0.62, 95% CI=0.21-1.85) cancers in multivariate-adjusted models. These estimates did not change appreciably after further adjustments. Conclusions: This study provides evidence that chronic periodontitis is positively associated with risk of lung and colorectal cancer in postmenopausal women. These results need to be interpreted cautiously given the small number of incident cancer cases. Further research utilizing a larger sample is warranted to confirm these results. Citation Format: Xiaodan Mai, Jo L. Freudenheim, Michael J. LaMonte, Kathleen M. Hovey, Christopher A. Andrews, Robert J. Genco, Jean Wactawski-Wende. Periodontal disease severity and incident cancer in postmenopausal women: the Buffalo OsteoPerio Study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 256. doi:10.1158/1538-7445.AM2014-256

Short‐term clinical results of Nobel Direct implants: a retrospective multicentre analysis

The present retrospective clinical study was undertaken to evaluate the survival rate and marginal bone conditions around Nobel Direct one-piece implants. The purpose was also to compare the results with when these implants are used for immediate/early loading with implants allowed to heal before loading. Forty-three consecutive patients previously treated with 117 Nobel Direct implants at four different centres were evaluated. The implants had been used in both jaws for treatment after loss of single and multiple teeth. Immediate/early loading (within 2 weeks) with a provisional crown/bridge was applied to 95 implants, while 22 implants healed unloaded for 6 weeks to 6 months before loading. Calculations of marginal bone loss were performed in radiographs taken at placement and after an average of 10.2 months (range 1-18 months) of loading. Six (5.1%) of the 117 implants were removed during the follow up. All failed implants belonged to the immediate/early loading group giving a failure rate of 6.3% for this group and 0% for two-stage implants. The failure rate was higher for flapless (7.9%) than for flap surgery (0%). The marginal bone loss was -2.4 mm (SD 1.5) for all implants, while 37.6% showed more than 3 mm of loss during the follow up. Bone loss increased with time of follow up. Implants subjected to immediate/early loading showed more bone loss than two-stage implants: -2.6 mm (SD 1.5) vs. -1.6 mm (SD 1.1). Moreover, 41.3% of immediately loaded and 22.7% of two-stage implants presented with more than 3 mm of bone loss. This short-term retrospective analysis showed a poor clinical outcome of Nobel Direct implants. Extensive marginal bone loss (>3 mm) was found around more than 1/3 of the implants evaluated. Less resorption and no failures were experienced when implants were allowed to heal from 6 weeks to 6 months before occlusal loading. Within the limitations of the present study design, data indicate that immediate loading, the use of this implant for multi-unit constructions and flapless surgery are risk factors for failure of Nobel Direct implants.

Occurrence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia in juvenile periodontitis.

The occurrence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia in subgingival plaque in 24 juvenile periodontitis patients was determined using DNA probe. 36 samples of subgingival plaque from 36 pockets having > or = 6 mm depth, > or = 3 mm of loss of attachment, and bleeding on probing and/or suppuration were taken from 18 patients with localized juvenile periodontitis (LJP, age range 12-24 years); and 12 samples from 6 patients with generalized juvenile periodontitis (GJP, age range 23-26 years). As control, an equal numbers of samples from healthy sites in the same patients were studied. P. gingivalis was found in 17 of 18 LJP patients, and in 31 of 36 diseased sites in those patients. P. intermedia was found in 15 out of the 18 LJP patients and in 28 of the 36 diseased sites. A. actinomycetemcomitans was present in 7 of the 18 LJP patients, and in 9 of the 36 diseased sites, and was not found in any GJP patients. All GJP patients had P. gingivalis (11 out of 12 diseased sites) and P. intermedia (all of the diseased sites). None of the three bacterial species was detected in healthy sites of GJP patients, and were found in healthy sites in only 2 of 18 LJP patients. The high prevalence and high levels of P. gingivalis and P. intermedia found in the LJP and GJP patients studied, suggest that there are populations affected by juvenile periodontitis in which this type of periodontitis is more associated with these species than with A. actinomycetemcomitans.

Periodontal attachment loss in independently living older adults in Ontario, Canada.

This paper describes the periodontal disease experience of a community-dwelling population aged 50 years and older, living in four communities in Ontario, Canada. The periodontal status of this population was assessed using attachment loss and the extent and severity index. Attachment loss was measured at two sites on each tooth using a pressure-sensitive periodontal probe. Complete periodontal data were obtained on 624 subjects. The mean number of sites per subject was 37.9. In line with recent US studies, the diagnostic threshold for a diseased or previously diseased site was set at 2 mm of loss. The overall mean attachment loss was 2.95 mm, with 19.7 percent of subjects having an overall mean attachment loss of 4.00 mm or more. The proportion of sites examined with loss of attachment of 2 mm or more was 77 percent. The severity of disease, defined as the average distance between the base of the sulcus or pocket and a point 1.00 mm apical to the cemento-enamel junction in sites with loss of 2 mm or more was 2.44 mm. These data indicate that the extent and severity of disease in this population were greater than that reported by some recent studies in the US. Taken together, the results of these studies suggest that there is some variation in the periodontal disease experience of population subgroups across North America.

Periodontal conditions in adult patients with cleft lip, alveolus, and palate.

The present study assessed the progression rate of periodontal disease over 8 years in a group of 52 adult patients with various forms of cleft lip, alveolus, and palate considered at risk for progression of periodontal disease. Of special interest was the evaluation of periodontal disease progression at sites adjacent to cleft regions compared to changes found at control sites not directly affected by such defects. High incidences of generalized plaque accumulation and bleeding on probing were noted at both examinations in 1979 and 1987. A mean apical shift of the clinical attachment level amounting to 0.2 mm had occurred over the 8-year observation period. A slight apical displacement of the mesial and distal mean crestal alveolar bone was also noted. The rate of progression of periodontal disease over the 8 years was not found to be different at statistically significant levels at cleft sites compared to control sites. However, the results of this study documented that the cumulative periodontal destruction at 26 to 28 years of age was statistically significant and more pronounced at cleft sites as revealed by greater probing pocket depth and loss of clinical attachment. The differences between test and control sites amounted to 0.3 and 0.4 mm respectively for probing depth and 0.6 mm for loss of clinical attachment. In addition, the discrepancy between alveolar bone height and the levels of the clinical attachment at cleft sites demonstrated the presence of a long supracrestal connective tissue attachment adjacent to cleft defects. Therefore, the alveolar bone height as visualized in radiographs at such sites was considered an unreliable diagnostic tool for the assessment of the degree of periodontal destruction.

Periodontal Conditions in Adult Patients with Cleft Lip, Alveolus, and Palate

The present study assessed the progression rate of periodontal disease over 8 years in a group of 52 adult patients with various forms of cleft lip, alveolus, and palate considered at risk for progression of periodontal disease. Of special interest was the evaluation of periodontal disease progression at sites adjacent to cleft regions compared to changes found at control sites not directly affected by such defects. High incidences of generalized plaque accumulation and bleeding on probing were noted at both examinations in 1979 and 1987. A mean apical shift of the clinical attachment level amounting to 0.2 mm had occurred over the 8-year observation period. A slight apical displacement of the mesial and distal mean crestal alveolar bone was also noted. The rate of progression of periodontal disease over the 8 years was not found to be different at statistically significant levels at cleft sites compared to control sites. However, the results of this study documented that the cumulative periodontal destruction at 26 to 28 years of age was statistically significant and more pronounced at cleft sites as revealed by greater probing pocket depth and loss of clinical attachment. The differences between test and control sites amounted to 0.3 and 0.4 mm respectively for probing depth and 0.6 mm for loss of clinical attachment. In addition, the discrepancy between alveolar bone height and the levels of the clinical attachment at cleft sites demonstrated the presence of a long supracrestal connective tissue attachment adjacent to cleft defects. Therefore, the alveolar bone height as visualized in radiographs at such sites was considered an unreliable diagnostic tool for the assessment of the degree of periodontal destruction.

The Cast Brace and Tibial Plateau Fractures

Three hundred six tibial plateau fractures treated at the authors' institutions and in private practice were analyzed in relation to the use of a cast brace or fracture brace. One hundred forty-one of these patients had had a cast brace or fracture brace as part of their treatment program, either as the primary fracture treatment or after open reduction or traction. The aims of this study were (1) to determine if cast bracing could maintain alignment, fracture position, and range of motion and (2) to compare its results with those of other major long-term studies of similar fractures. There were 85 lateral, 24 medial, and 32 bicondylar fractures. Cast bracing was used for one to 17 weeks, with a mean of eight weeks. Ninety-nine of the 141 patients were followed for at least one year. Eighty-two of the patients maintained alignment with less than 5 degrees of deformity, and fracture position was maintained in 85% of cases, with only 15% having 4-8 mm of loss of position. Medial plateau and subcondylar fractures had an increased incidence of fracture position loss. Ninety-seven percent of patients had greater than 90 degrees of flexion, and 90% had full extension, i.e., less than 5 degrees of contracture. Pain was minimal or absent after heavy exercise in 90% of patients using cast bracing. Arthritic changes on roentgenographic analysis were absent or mild in 93.5% and moderate or severe in 6.5% of patients. Complications, including phlebitis, pulmonary emboli, wound infection, hardware slippage, and skin slough, occurred in nine patients.(ABSTRACT TRUNCATED AT 250 WORDS)