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Lingual Aspect (lingual + aspect)
Selected AbstractsImplants in fresh extraction sockets: a prospective 5-year follow-up clinical studyCLINICAL ORAL IMPLANTS RESEARCH, Issue 12 2008Daniele Botticelli Abstract Objective: The aim of this prospective study was to evaluate the 5-year clinical outcome of the ,immediate implants.' Material and methods: One week after the cementation of the prosthesis, a clinical baseline examination was carried out. Clinical measurements were performed of the following: plaque, mucositis, probing pocket depth, and soft tissue position. The height of the keratinized mucosa was measured at the buccal/lingual aspects. Standardized intra-oral radiographs were taken. The marginal level of bone to implant contact [radiographic (Rx) bone level] was measured, and Rx bone level change over time was evaluated. The clinical/radiographic measurements were repeated on a yearly basis. The subjects were enrolled in a carefully supervised oral hygiene program. Results and conclusion: It was demonstrated that ,immediate implants' that were loaded after 5,7 months had a high success rate. During the 5-year interval, no implant was lost, and the mean Rx bone level at the implants was maintained or even improved. The plaque and mucositis scores were low (<20%) at baseline and at all re-examinations. Implant sites located adjacent to the teeth showed bone gain during the initial period while sites that were facing edentulous zones lost some bone. [source] Alveolar ridge augmentation using implants coated with recombinant human growth/differentiation factor-5: histologic observationsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 8 2010Giuseppe Polimeni Polimeni G, Wikesjö UME, Susin C, Qahash M, Shanaman RH, Prasad HS, Rohrer MD, Hall J. Alveolar ridge augmentation using implants coated with recombinant human growth/differentiation factor-5: histologic observations. J Clin Periodontol 2010; 37: 759-768 doi: 10.1111/j.1600-051X.2010.01579.x. Abstract Objectives: In vitro and in vivo preclinical studies suggest that growth/differentiation factor-5 (GDF-5) may induce local bone formation. The objective of this study was to evaluate the potential of recombinant human GDF-5 (rhGDF-5) coated onto an oral implant with a purpose-designed titanium porous oxide surface to stimulate local bone formation including osseointegration and vertical augmentation of the alveolar ridge. Materials and Methods: Bilateral, critical-size, 5 mm, supraalveolar peri-implant defects were created in 12 young adult Hound Labrador mongrel dogs. Six animals received implants coated with 30 or 60 ,g rhGDF-5, and six animals received implants coated with 120 ,g rhGDF-5 or left uncoated (control). Treatments were alternated between jaw quadrants. The mucoperiosteal flaps were advanced, adapted, and sutured to submerge the implants for primary intention healing. The animals received fluorescent bone markers at weeks 3, 4, 7, and 8 post-surgery when they were euthanized for histologic evaluation. Results: The clinical examination showed no noteworthy differences between implants coated with rhGDF-5. The cover screw and implant body were visible/palpable through the alveolar mucosa for both rhGDF-5-coated and control implants. There was a small increase in induced bone height for implants coated with rhGDF-5 compared with the control, induced bone height averaging (±SD) 1.6±0.6 mm for implants coated with 120 ,g rhGDF-5 versus 1.2±0.5, 1.2±0.6, and 0.6±0.2 mm for implants coated with 60 ,g rhGDF-5, 30 ,g rhGDF-5, or left uncoated, respectively (p<0.05). Bone formation was predominant at the lingual aspect of the implants. Narrow yellow and orange fluorescent markers throughout the newly formed bone indicate relatively slow new bone formation within 3,4 weeks. Implants coated with rhGDF-5 displayed limited peri-implant bone remodelling in the resident bone; the 120 ,g dose exhibiting more advanced remodelling than the 60 and 30 ,g doses. All treatment groups exhibited clinically relevant osseointegration. Conclusions: rhGDF-5-coated oral implants display a dose-dependent osteoinductive and/or osteoconductive effect, bone formation apparently benefiting from local factors. Application of rhGDF-5 appears to be safe as it is associated with limited, if any, adverse effects. [source] Stability of crestal bone level at platform-switched non-submerged titanium implants: a histomorphometrical study in dogsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2009Jürgen Becker Abstract Objectives: To investigate the influence of platform switching on crestal bone level changes at non-submerged titanium implants over a period of 6 months. Material and Methods: Titanium implants (n=72) were placed at 0.4 mm above the alveolar crest in the lower jaws of 12 dogs and randomly assigned to either matching or non-matching (circumferential horizontal mismatch of 0.3 mm) healing abutments. At 4, 8, 12, and 24 weeks, dissected blocks were processed for histomorphometrical analysis. Measurements were made between the implant shoulder (IS) and the apical extension of the long junctional epithelium (aJE), the most coronal level of bone in contact with the implant (CLB), and the level of the alveolar bone crest (BC). Results: At 24 weeks, differences in the mean IS,aJE, IS,CLB, and IS,BC values were 0.2 ± 1.2, 0.3 ± 0.7, and 0.3 ± 0.8 mm at the buccal aspect, and 0.2 ± 0.9, 0.3 ± 0.5, and 0.3 ± 0.8 mm at the lingual aspect, respectively. Comparisons between groups revealed no significant differences at either the buccal or the lingual aspects. Conclusions: It was concluded that (i) bone remodelling was minimal in both groups and (ii) platform switching may not be of crucial importance for maintenance of the crestal bone level. [source] Bone healing around implants placed in a jaw defect augmented with Bio-Oss®JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 11 2000An experimental study in dogs Abstract The present experiment was carried out to study some tissue reactions around implants that were placed in an edentulous ridge which had been augmented with deproteinized natural bovine cancellous bone mineral. In 4 male beagle dogs, the premolars in the right side of the mandible were extracted and a large buccal ridge defect was created by mechanical means. The bone plate at the lingual aspect of the defect was left intact. 5 months later, the distal 2/3 of the defect area was augmented with Bio-Oss® (Geistlich Sons Ltd, Wolhusen, Switzerland) mixed with a fibrin sealer (Tisseel®, Immuno AG, Vienna, Austria). After 3 months of healing, 3 fixtures (Astra Tech AB, Mölndal, Sweden; TiO-blast; 8×3.5 mm) were installed in the mandible; 2 were placed in the augmented portion and 1 was placed in the non-augmented portion of the defect. After a healing period of 3 months, abutment connection was performed and a plaque control period initiated. 4 months later, the dogs were sacrificed and each implant region was dissected. The tissue samples were dehydrated, embedded in plastic, sectioned in the bucco-lingual plane and examined in the light microscope. It was observed that osseointegration failed to occur to implant surfaces within an alveolar ridge portion previously augmented with Bio-Oss®. In the augmented portion of the crest, the graft particles were separated from the host tissue as well as from the implant by a well-defined connective tissue capsule. Although the lingual aspect of all fixtures (test and control) was in contact with hard tissue at the time of installation, after 4 months of function, a deep vertical bone defect frequently had formed at the lingual surface of the implants. It was concluded that in this model (i) Bio-Oss® failed to integrate with the host bone tissue and (ii) no osseointegration occurred to the implants within the augmented portion of the crest. [source] Effect of bone chip orientation on quantitative estimates of changes in bone mass using digital subtraction radiographyJOURNAL OF PERIODONTAL RESEARCH, Issue 3 2003André Mol Objectives:, To assess the effect of the orientation of arbitrarily shaped bone chips on the correlation between radiographic estimates of bone loss and true mineral loss using digital subtraction radiography. Methods:, Twenty arbitrarily shaped bone chips (dry weight 1,10 mg) were placed individually on the superior lingual aspect of the interdental alveolar bone of a dry dentate hemi-mandible. After acquiring the first baseline image, each chip was rotated 90 degrees and a second radiograph was captured. Follow-up images were created without the bone chips and after rotating the mandible 0, 1, 2, 4, and 6 degrees around a vertical axis. Aluminum step tablet intensities were used to normalize image intensities for each image pair. Follow-up images were registered and geometrically standardized using projective standardization. Bone chips were dry ashed and analyzed for calcium content using atomic absorption. Results:, No significant difference was found between the radiographic estimates of bone loss from the different bone chip orientations (Wilcoxon: P > 0.05). The correlation between the two series of estimates for all rotations was 0.93 (Spearman: P < 0.05). Linear regression analysis indicated that both correlates did not differ appreciably ( and ). Conclusion:, It is concluded that the spatial orientation of arbitrarily shaped bone chips does not have a significant impact on quantitative estimates of changes in bone mass in digital subtraction radiography. These results were obtained in the presence of irreversible projection errors of up to six degrees and after application of projective standardization for image reconstruction and image registration. [source] Precision of Fit of Two Margin Designs for Metal-Ceramic CrownsJOURNAL OF PROSTHODONTICS, Issue 4 2007Penwadee Limkangwalmongkol DDS Statement of Problem: Although metal-ceramic restorations are widely used, there is a lack of information about how the fit is affected by margin designs. Purpose: This study measured and compared the precision of fit of metal-ceramic crowns with two margin designs. Material and Methods: Thirty-two extracted human premolar teeth were prepared for complete-coverage restorations with an internally rounded shoulder preparation. Impressions were made from all teeth, and master dies were poured with improved stone type V. MC crowns were fabricated with a porcelain-butt margin on the buccal aspect (n = 32) and a feather-edge metal margin on the lingual aspect (n = 32), which served as a control group. Precision of fit was measured three times at the mid-buccal and mid-lingual margins of each crown with a profilometer. The data were statistically analyzed with the paired t -test (, < .05). Results: Mean marginal gap size of porcelain-butt margins was 27.93 ,m (±15.84) and of feather-edge metal margins 42.43 ,m (±24.12). The marginal gap size of feather-edge metal margins was statistically significantly greater than that of porcelain-butt margins (p = 0.0045). Conclusion: The marginal fit of porcelain-butt margins was significantly better than that of feather-edge metal margins. Clinical Implications: Porcelain-butt margins in this study had a better marginal fit than feather-edge metal margins, and thus have given clinicians evidence to prefer the use of porcelain-butt margins. [source] Masticatory stress and the mechanics of "wishboning" in colobine jawsAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2009David J. Daegling Abstract Cercopithecoid monkeys experience relatively high strains along the lingual aspect of the mandibular symphysis because of lateral transverse bending of the mandibular corpora ("wishboning") during mastication. Hylander (Am J Phys Anthropol 64 (1984) 1,46; Am Zool 25 (1985) 315,330) demonstrated that the distribution of strains arising from wishboning loads is comprehensible with reference to the mechanics of curved beams. Theory of curved beams suggests that lingual tensile strains are some multiple of labial compressive strains, yet limitations of experimental methods and uncertainty in estimating parameters needed for theoretical calculations have confounded attempts to characterize the magnitude of this disparity of normal strains. We evaluate the theoretical disparity of normal strains in wishboning in comparison to in vitro strains collected under controlled loads for a sample of mandibles representing two colobine species (N = 6). These data suggest that in colobine monkeys, maximum normal lingual strains should be at least twice maximum labial strains. In addition, we reexamine the distribution of symphyseal stress under an assumption of asymmetric bending, a general approach for calculation of stress appropriate for members that lack a plane of symmetry and are bent along an axis that is not coincident with the member's principal axes. Under asymmetric bending in colobine mandibles, the effect of symphyseal inclination on lingual strain is mitigating at the superior transverse torus and exacerbating at the inferior transverse torus. Relative compliance of colobine mandibular bone further supports the hypothesis that the structural and material properties of the colobine mandibular symphysis do not represent a morphological strategy for minimizing masticatory strain. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] Stability of crestal bone level at platform-switched non-submerged titanium implants: a histomorphometrical study in dogsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2009Jürgen Becker Abstract Objectives: To investigate the influence of platform switching on crestal bone level changes at non-submerged titanium implants over a period of 6 months. Material and Methods: Titanium implants (n=72) were placed at 0.4 mm above the alveolar crest in the lower jaws of 12 dogs and randomly assigned to either matching or non-matching (circumferential horizontal mismatch of 0.3 mm) healing abutments. At 4, 8, 12, and 24 weeks, dissected blocks were processed for histomorphometrical analysis. Measurements were made between the implant shoulder (IS) and the apical extension of the long junctional epithelium (aJE), the most coronal level of bone in contact with the implant (CLB), and the level of the alveolar bone crest (BC). Results: At 24 weeks, differences in the mean IS,aJE, IS,CLB, and IS,BC values were 0.2 ± 1.2, 0.3 ± 0.7, and 0.3 ± 0.8 mm at the buccal aspect, and 0.2 ± 0.9, 0.3 ± 0.5, and 0.3 ± 0.8 mm at the lingual aspect, respectively. Comparisons between groups revealed no significant differences at either the buccal or the lingual aspects. Conclusions: It was concluded that (i) bone remodelling was minimal in both groups and (ii) platform switching may not be of crucial importance for maintenance of the crestal bone level. [source] Clinical characteristics at implants with a history of progressive bone lossCLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2008Christer Fransson Abstract Objective: The aim of the present study was to describe the clinical characteristics at implants with a history of progressive bone loss. Material and methods: Eighty-two out of 184 previously identified subjects with a history of progressive bone loss volunteered for the study. Clinical assessments of plaque, bleeding on probing (BoP), probing pocket depth (PPD), suppuration following probing (Pus), presence of calculus on implants surfaces (Calc) and ,recession' i.e. the mucosal margin in level with or apical of the fixture/abutment junction were performed at the mesial, distal, buccal and lingual aspects of each implant and without removing the bridge constructions. Results: It was demonstrated that the frequencies of BoP, Pus, ,recession' and PPD,6 mm were higher at implants with than without ,progressive' bone loss. In addition, smokers had larger numbers of affected implants than non-smokers, and the proportion of affected implants that exhibited Pus and PPD,6 mm was higher in smokers than in non-smokers. The logistic regression analysis revealed that the findings of Pus, ,recession' and PPD,6 mm at an implant in a smoking subject had a 69% accuracy in identifying the history of progressive bone loss. Conclusion: The results from this study demonstrate an association between clinical signs of pathology and bone loss at implants. It is recommended to include clinical assessments in the evaluation of implant therapy. [source] | ||||||||||