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Study Models (study + models)
Selected AbstractsChange in supporting tissue following loss of a permanent maxillary incisor in childrenDENTAL TRAUMATOLOGY, Issue 6 2007Helen D. Rodd Abstract,,, Alveolar bone resorption is an inevitable consequence of tooth loss and may be detrimental to long-term dental aesthetics and function. The aim of the present study was to quantify the degree of tissue resorption following the loss of a permanent incisor in a young population. The study group comprised 11 boys and five girls who all required the extraction of a permanent maxillary central incisor due to trauma-related sequelae. Mean age at tooth loss was 10.8 years. Upper alginate impressions were taken at regular intervals following tooth loss and were cast in yellow dental stone. Study models were sectioned longitudinally through the mid-point of both the maxillary incisor socket and the contra-lateral incisor to provide a thin plaster section. Digital photographs were acquired of the edentulous (A1) and dentate (A2) surfaces of this section and image analysis software was employed to quantify the surface area of both A1 and A2. At 3 months postextraction, mean A1 was 15.7% less than mean A2. By 6 months mean A1 had further reduced and was 25.3% less than that of the corresponding dentate alveolus. However, at subsequent time intervals following tooth extraction (>6 months), tissue loss appeared to stabilise with an overall reduction in tissue area remaining at 22%. This reduction in supporting tissue area was found to be highly statistically significant (P = 0.002, anova). Furthermore, girls appeared to have an overall greater degree of tissue loss than boys (P = 0.015). Further research is indicated to explore factors influencing the degree of tissue loss following incisor extraction and the benefit of therapeutic interventions in limiting this resorption. [source] Clinical pharmacology and therapeutic use of antioxidant vitaminsFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 2 2007Ramón Rodrigo Abstract The clinical use of antioxidants has gained considerable interest during the last decade. It was suggested from epidemiological studies that diets high in fruits and vegetables might help decrease the risk of cardiovascular disease. Therefore, supplements of vitamins C and E were applied through protocols aimed to prevent diseases such as atherosclerosis, preeclampsia or hypertension, thought to be mediated by oxidative stress. Despite the biological properties of these vitamins could account for an effective protection, as shown by several clinical and experimental studies, their efficacy remains controversial in the light of some recent clinical trials and meta-analyses. However, the methodology of these studies, criteria for selection of patients, the uncertain extent of progression of the disease when initiating supplementation, the lack of mechanistic studies containing basic scientific aspects, such as the bioavailability, pharmacokinetic properties, and the nature of the antioxidant sources of vitamins, could account for the inconsistency of the various clinical trials and meta-analyses assessing the efficacy of these vitamins to prevent human diseases. This review presents a survey of the clinical use of antioxidant vitamins E and C, proposing study models based on the biological effects of these compounds likely to counteract the pathophysiological mechanisms able to explain the structural and functional organ damage. [source] The interdental gingiva, a visible guide for placement of mini-implantsORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 1 2009YS Chun Structured Abstract Authors,,, Chun YS, Lee SK, Wikesjö UME, Lim WH Objectives,,, To determine whether the tip of the interdental gingiva can serve as a visible guide for placement of mini-implants. Setting and Sample population,,, Computer tomography (CT) images from 15 males and 15 females (mean age 27 years, range: 23,35 years) were used to evaluate the distance from the tip of the interdental gingiva to the alveolar crest from the central incisor to the 1st molar. The distance from a reference point to the tip of interdental gingiva was recorded from study models using a caliper. The distance between the reference point and the alveolar crest was recorded using CT and added to the model recordings thus providing the distance from the tip of interdental gingiva to the alveolar crest for the various interdental sites. Two-way anova and Student,Newman,Keuls test for multiple comparisons were used for the statistical analysis. Results,,, There was no significant difference in the distance from the tip of interdental gingiva to the alveolar crest between maxilla and mandible. The distance between the tip of interdental gingiva and the alveolar crest at the central/lateral incisors was the shortest compared with that of other sites. There was also a statistically significant difference between the male and female groups except for the maxillary 2nd premolar/1st molar interradicular site. Conclusion,,, The tip of interdental gingiva appears a reasonable visual guide for the placement of mini-implants for orthodontic anchorage. [source] Endodontic sequelae of dental erosionAUSTRALIAN DENTAL JOURNAL, Issue 2 2003K. Sivasithamparam Abstract Background: The incidence of pulp involvement in patients with excessive wear has not been extensively documented. Methods: Clinical records of 448 patients with excessive tooth wear were reviewed and 52 cases (11.6 per cent) with near or frank pulp exposures or root canal treatments were found and their numbers and sites were tabulated. Light microscopy of study models was used to determine aetiology at each site of exposure as attrition, erosion or abrasion, scanning electron microscopy (SEM) was performed on some individual teeth. Results: Forty sites of near exposure and 57 sites of frank exposures or root canal treatments were found, some cases had both types of exposure. The commonest sites exposed by erosion were the palatal surfaces of maxillary, and the incisal surfaces of mandibular anterior teeth. Posterior teeth were not commonly affected. Toothbrush abrasion had exacerbated some lesions as shown by SEM. Conclusions: Endodontic sequelae were found in 11 per cent of tooth wear patients as late stages of dental erosion. Near and frank exposures of the pulp thus constitute a small but significant, problem for the Australian dental profession's concern in the management of the tooth wear cases. [source] Single Implants and Buccal Bone Grafts in the Anterior Maxilla: Measurements of Buccal Crestal Contours in a 6-Year Prospective Clinical StudyCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 3 2005Odont Dr/PhD, Torsten Jemt DDS ABSTRACT Background: Patients provided with buccal bone grafts seem to lose a substantial part of the graft in the short term. Purpose: To measure long-term changes in buccal and proximal tissue volumes after local bone grafting and single implant treatment. Materials and Methods: Eight of 10 originally treated male patients were followed up for 6 years after treatment with buccal bone grafts in the central incisor region. After a healing time of 6 months, a two-stage implant surgery procedure was performed followed by single crown placement. Clinical photographs and impressions were taken prior to the surgical interventions and after crown placement and at first and fifth annual checkups. The photographs were analyzed with regard to papilla regeneration by means of a clinical papilla index. The models were used to measure the clinical length of teeth and tooth movements adjacent to the implants. Changes in buccal crest volume during the study period were measured by means of optical scanning of obtained study models. Results: Papillae volume increased significantly (p < .05) during the first year, thereafter showing a slow further increase during the 4 following years. Three of the patients (38%) presented small movements of their adjacent central incisor in a vertical or palatal direction of less than 1 mm during the follow-up period. All patients showed resorption during the first year after grafting (p < .01), in which three patients (38%) had lost basically all of increased volume at second surgery. After abutment or crown placement, all patients showed an increased volume (p < .01), followed by an average reduction during the first year, reaching a significant level in the apical part of the crest (p < .05). Thereafter, a relatively stable average situation was observed during the following 4 years, with individual variations, however. Conclusion: Local bone grafting seems to create sufficient bone volume for implant placement after 6 months, but individual variations in resorption pattern make the grafting procedure unpredictable for long-term prognosis. Instead, the abutment and the crown seem to play a more important role for building up and maintaining the buccal contour in the coronal part of the crest long term. [source] Measurements of Buccal Tissue Volumes at Single-Implant Restorations after Local Bone Grafting in Maxillas: A 3-Year Clinical Prospective Study Case SeriesCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2 2003Odont PhD, Torsten Jemt LDS ABSTRACT Purpose: The purpose of this study was to measure changes in buccal and proximal tissue volumes after local bone grafting and single-implant treatment. Materials and Methods: Ten patients were provided with buccal bone grafts 6 months prior to implant treatment in central upper incisor regions. Following a healing time of 6 months, abutments and single-implant crowns were installed and followed up for 2 years. Clinical photographs and impressions were taken prior to the surgical intervention as well as after crown placement and at first and second annual checkups. The photographs and study models were analyzed with regard to papilla regeneration and changes in buccal crest volume during the study period by means of a clinical papilla index and optical scanning of study models. Results: All bone grafts healed without problems. A significant reduction of the buccal crest volume (-50%, p <.01) was observed in the grafted area before abutment connection. However, a significant increase of tissue volume (+100%, p <.05) was noticed at the subsequent crown placement, followed by a second but slow reduction of the volume during the following 2 years of function. The interdental papillae increased significantly (p <.05) in volume during the first year, almost completely filling up the embrasure areas after 2 years. Conclusions: It may be concluded that local bone grafting seems to be a valuable protocol to create sufficient bone volume for implant placement. However, significant resorption of the graft may be present, which reduces the impact of grafting on the esthetic outcome. Instead, placement of the abutment cylinder and the crown seems to play a more important role for reestablishing the tissue volume at the implant-supported single crowns. [source] | ||||||||||