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Coronal Position (coronal + position)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

In vitro evaluation of marginal and internal adaptation after occlusal stressing of indirect class II composite restorations with different resinous bases

EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2003
Didier Dietschi
Composite inlays are indicated for large cavities, which frequently extend cervically into dentin. The purpose of this study was to compare in vitro the marginal and internal adaptation of class II fine hybrid composite inlays (Herculite, Kerr) made with or without composite bases, having different physical properties. Freshly extracted human molars were used for this study. The base extended up to the cervical margins on both sides and was made from Revolution (Kerr), Tetric flow (Vivadent), Dyract (Detrey-Dentsply) or Prodigy (Kerr), respectively. Before, during and after mechanical loading (1 million cycles, with a force varying from 50 to 100 N), the proximal margins of the inlay were assessed by scanning electron microscopy. Experimental data were analysed using non-parametric tests. The final percentages of marginal tooth fracture varied from 30.7% (no base) to 37.6% (Dyract). In dentin, percentages of marginal opening varied from 9.2% (Tetric Flow) to 30.1% (Prodigy), however, without significant difference between base products. Mean values of opened internal interface with dentin varied from 11.06% (Tetric Flow) to 28.15% (Prodigy). The present results regarding dentin adaptation confirmed that the physical properties of a base can influence composite inlay adaptation and that the medium-rigid flowable composite Tetric Flow is a potential material to displace, in a coronal position, proximal margins underneath composite inlays. [source]

Extent of peri-implantitis-associated bone loss

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 4 2009
Christer Fransson
Abstract Objective: The purpose of the present study was to describe the extent of peri-implantitis-associated bone loss with regard to implant position. Material and methods: Patient files and intra-oral radiographs from 182 subjects were analysed. Among the 1070 examined implants, 419 exhibited peri-implantitis-associated bone loss. The position of each implant within the jaw and fixed reconstructions was determined. In the radiographs the distance between the abutment-fixture junction and the most coronal position of bone to implant contact was assessed at the 419 "affected" implants using a magnifying lens (× 7) with a 0.1 mm graded scale. Results: About 40% of the implants in each subject was affected by peri-implantitis-associated bone loss. The proportion of such implants varied between 30% and 52% in different jaw positions and the most common position was the lower front region. In addition, affected implants were found in larger proportions among "mid" than "end" abutments irrespective of supporting fixed complete or fixed partial dentures. Conclusion: It is suggested that peri-implantitis occurs in all jaw positions and that an "end"-abutment position in a fixed reconstruction is not associated with an enhanced risk for peri-implantitis. [source]

Fibre retention osseous resective surgery: a novel conservative approach for pocket elimination

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 2 2007
Gianfranco Carnevale
Abstract Aim and Background: The position of the most apical inter-dental portion of the alveolar crest is classically used in osseous resective surgery (ORS) to establish the amount of the inter-proximal and buccal/lingual bone resection. Supracrestal fibres connected to the root cementum are always present coronal to the alveolar crest both in healthy and diseased sites. The aim of this paper is to report a novel surgical approach that combines the classical method of osseous resection with the gingival fibre retention technique. Material and Methods: A description of the surgical procedure in four steps is provided (flap design, marginal soft tissue removal and fibre retention, ORS, suture of the flap). Results and Conclusion: The proposed technique shifts the bottom of the defect in a more coronal position at the level of the connective tissue fibre attachment, establishing a more conservative supporting bone resection. [source]

Subcrestal placement of two-part implants

CLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2009
Maria Welander
Abstract Objective: The aim of the present experiment was to study the healing around two-part implants that were placed in a subcrestal position. Material and methods: Five mongrel dogs, about 2 years old, were included. The mandibular premolars and the first, second and third maxillary premolars were extracted. Three months later two test and two control implants (OsseoSpeedÔ, 3.5 mm × 8 mm) were placed in one side of the mandible. The implants were placed in such a way that the implant margin was located 2 mm apical to the bone crest. In the test implants, the surface modification extended to the implant margin and, thus, included the shoulder part of the implant. Regular abutments with a turned surface (ZebraÔ) were connected to the control implants, while experimental abutments with a modified surface (TiOblastÔ) were connected to the test implants. A plaque control program that included cleaning of implants and teeth every second day was initiated. Four months later the dogs were euthanized and biopsies were obtained and prepared for histological analysis. Results: The marginal bone level at the test implants was identified in a more coronal position than that at the control implants. In 40% of the test implants, the bone-to-implant contact extended coronal of the abutment/fixture (A/F) border, i.e. in contact with the abutment part of the implant. The connective tissue portion of the peri-implant mucosa that was facing the test abutments contained a higher density of collagen and a smaller proportion of fibroblasts than that at the control sites. Conclusion: It is suggested that osseointegration may occur coronal to the A/F interface of two-part implants. Such a result, however, appears to depend on the surface characteristics of the implant components. [source]