Periodontal repair in dogs: effect of root surface treatment with stannous fluoride or citric acid on root resorption

This study evaluated healing, with emphasis on root resorption, following root surface treatment with 1% aqueous stannous fluoride (SnF2), saturated citric acid (CA), or saline control (C) in conjunction with periodontal flap surgery. Supraalveolar periodontal defects were surgically created and immediately treated in the mandibular premolars in 6 beagle dogs. The defect height approximated 5 to 6 mm from the reduced alveolar bone to the cemento-enamel junction. Root treatments were rotated between experimental teeth within jaw quadrants and duplicated in left and right quadrants in the dogs. Flaps were raised to cover most of the crowns of the teeth and sutured. The dogs were sacrificed 12 weeks after surgery and tissue blocks with teeth and adjacent structures were processed for histometric analysis. SnF2-treated teeth healed with significantly longer junctional epithelium, less connective tissue repair to the root surface, and less bone regeneration than CA and C-treated teeth. New cementum formation was limited in all treatment groups. Root resorption was observed in almost all teeth exhibiting connective tissue repair, however to a lesser amount and not as frequent in SnF2 treated teeth due to limited connective tissue repair. No differences were found in amount and frequency of root resorption in CA and C-treated teeth. An inhibitory effect on root resorption of SnF2 could not be disclosed in this experiment, however, it may be concluded that CA treatment of the root surface in conjunction with reconstructive periodontal flap surgery does not seem to enhance root resorption.     

Applicability of osseointegrated oral implants in the rehabilitation of partial edentulism: a prospective multicenter study on 558 fixtures

Nine clinical centers using the Br?nemark System participated in a prospective study of 159 partially edentulous patients between 18 and 70 years of age. Clinical parameters evaluated were plaque index, gingivitis, pocket depth, bleeding index, tooth mobility, and stomatognathic function. Initially, 558 fixtures were placed and 521 remained in the study following prosthesis placement (199 prostheses in 154 patients). Fixtures were lost or unaccounted for because of nonintegration prior to prosthesis fabrication (19), patient withdrawal (11), prosthodontic reasons (6), and failure during prosthetic procedures (1). Failure was primarily attributable to unfavorable bone quality, sex (more in males), and smaller fixture size. Complications and failure related to other patient characteristics are presented. After 1 year of a 5-year study, preliminary results suggest that a success rate equal to or better than that obtained with edentulous patients may be expected.     

Microstructural investigations of strain-related collagen mineralization

Distraction osteogenesis in rabbit mandibles after osteotomy can be used as an experimental model to study the microstructural features of mineralization of callus under defined mechanical loads. Our aim was to study the relation between the micromotions in the gap and the resulting features of mineralization of the matrix. We found that assembly of collagen and formation of crystals depended on the magnitude of the mechanical stress applied. At physiological bone strains (2000 microstrains), the callus had collagen type I in a mature bone-like extracellular arrangement, whereas at 20000 microstrains bundles were orientated predominantly towards the tension vector. Maximum loads (200000 microstrains) resulted in disorganized assembly of the collagen. Quantitative energy-dispersive analysis by X-rays confirmed that high strains were associated with substantially lower concentrations of calcium and phosphate. In contrast to bone-like apatitic formation of crystals at physiological strains, significantly fewer but larger crystals were detected by electron diffraction analysis in samples exposed to high strains. We suggest that mechanical stress regulates the assembly and mineralization of collagen during distraction osteogenesis.     

Behandlung von frontobasalen Traumen und Polytraumen

Background: This paper describes the historical development as well as current concepts of frontobasal fracture treatment by maxillofacial surgeons. Treatment concept: Based on the experience of many years a diagnostic and therapeutic treatment concept was developed, which proved to be adequate in 320 patients with 90 frontobasal fractures in the last five years.     

Recommendations for optimal distraction protocols for various animal models on the basis of a systematic review of the literature

The principles of orthopaedic distraction osteogenesis (DO) have been successfully applied to the craniofacial skeleton, but the latency time, rate and rhythm of distraction, and length of the consolidation period that are optimal for long-bone distraction may be suboptimal for craniofacial DO. The aim of this study was to provide recommendations for optimal distraction parameters in animal experimental research on craniofacial DO. The data used were from studies, added to the PubMed database between 1 January 1973 and 1 January 2007, on the outcome of DO resulting from variations in a single distraction parameter while standardizing the other distraction parameters. Although experimental animal group sizes were rather small, especially in those studies that used large animals, and both skeletally mature and immature animals were used, the (in most cases quantitative) data provided useful information on the optimal parameters in craniofacial DO. A latency period may not be necessary at all. Distraction should be performed at a rate of 1mm/day (this may be halved when small animals such as rats are used) preferably with a continuous rhythm, followed by a consolidation period of 6-8 weeks. These recommendations can be used as basic guidelines for further animal experimental studies on craniofacial DO.     

Properties of a new root-end filling material

The purposes of this investigation were 2-fold: to study the physical properties and sealing ability of Viscosity Enhanced Root Repair Material (VERRM); and, to compare them with Mineral Trioxide Aggregate (MTA). VERRM has a composition similar to mineral trioxide aggregate, with handling characteristics and consistency similar to commercially available materials such as IRM and Super EBA. The pH, setting times, solubility, radiopacity, dimensional change upon setting, and apical sealing ability of VERRM were evaluated and compared to that of ProRoot MTA (GMTA) and ProRoot MTA (Tooth Colored Formula) (WMTA). The results showed that VERRM had physical properties similar to WMTA. VERRM and WMTA showed significantly greater dye penetration than GMTA (p < 0.05) when used as a root-end filling material. There was no significant difference in depth of dye penetration between VERRM and WMTA. Further development of VERRM is indicated to produce a biocompatible root-end filling material with superior handling characteristics.     

Reconstruction of severely resorbed edentulous maxillae using osseointegrated fixtures in immediate autogenous bone grafts

A surgical technique for rehabilitation of severely resorbed edentulous maxillae using fixed prostheses or overdentures supported by osseointegrated fixtures in immediate autogenous corticocancellous bone grafts from the ilium is described. The results of the first 23 consecutively treated patients are reviewed. The mean observation time was 4.2 years (range 1 to 10 years). A total of 124 fixtures was originally placed into the grafts, supplemented with 16 fixtures inserted later into seven of the jaws. Throughout their observation period, 17 of the patients had continuously stable prostheses. The remaining five had overdentures, and one patient had resorted to a conventional complete denture. After 4 years, 12 of 16 patients had continuously stable prostheses. Corresponding values at 5 years were 7 of 8 patients. Calculated from the date of abutment connection, 82.1% and 81.6% of the original fixtures were clinically stable and radiographically osseointegrated after 4 and 5 years in function, respectively. From the date of fixture placement, the corresponding figures were 75.3% and 73.8%, respectively. The mean marginal bone loss after the first year of prosthesis function was 1.49 mm. The annual marginal bone loss thereafter was about 0.1 mm. The results indicate that this technique is worthwhile for patients with extreme maxillary atrophy and who cannot wear conventional complete dentures.     

A comparison between anamnestic, rhinomanometric and radiological methods of diagnosing mouth-breathing

Three methods of evaluating the mode of breathing were applied in 119 children aged 7-15 years who were to start orthodontic treatment for various malocclusions. The three methods were: the history, rhinomanometric recording of the nasal airflow and determination of the size of the airway on profile and frontal cephalograms. The variables describing the mode of breathing were correlated with the facial morphology and the natural position of the head and the cervical spine as recorded with profile cephalometry. There were no correlations between the results of the evaluation of the mode of breathing obtained with the three methods. Nor were there any correlations between these and the position of the head or the cervical spine. A history of mouth-breathing, the rhinomanometrically determined airflow through the nose and the size of the airway on the profile cephalogram were, however, correlated with the long face morphology characteristic of mouth-breathing. A diagnosis of mouth-breathing should be based on different supplementary methods, the history and the size of the airway on the profile cephalogram being at least as valuable as the rhinomanometric recordina.     

Association between genetic risk score and periodontitis onset and progression: a pilot study

Aim

Recent research has focused attention on the single nucleotide polymorphisms (SNPs) involved in the host response in periodontitis. However, so as to combine the relatively small effects of individual genes the use of multi locus genetic risk (GRS) has been proposed. This study aims to evaluate whether the genetic risk score may predict periodontitis onset and progression.

Materials and methods

Fifty patients were divided into various groups according to periodontal status. Total DNA was isolated from epithelial oral cells by a masked operator and the selected SNPs were analysed. A GRS was calculated using an additive model.

Results

We found a strong association only between TNF rs1800629 and diffused forms of periodontitis. Data show that GRS is able to discriminate diffused forms of periodontitis from localized ones. Finally, a progressive increase of the GRS is evident in advanced periodontitis in comparison with early forms.

Discussion

In recent years, research on genetic polymorphism has had limited success in predicting the susceptibility to periodontal disease. However, our results indicate that the use of the genetic risk score could be promising. Further studies are necessary to include data from multiple genes so as to confirm our result.     

Foreign body ingestion in dental practice

Most foreign bodies pass through the gastrointestinal tract uneventfully. The majority of the reported literature describes the management of ingested blunt objects. However, ingestion of sharp objects can still occur with a higher rate of perforation corresponding to treatment dilemmas. We report a case of inadvertently ingested sharp foreign body by a special child, which was retrieved by endoscopic guided forceps. Urgent endoscopic assessment and retrieval of recently ingested sharp dental foreign body is indicated and routine use of preventive measures such as rubber dam, gauze throat screens or floss ligatures is suggested.