Assem Soueidan

Experimental animal models in periodontology: a review.

In periodontal research, animal studies are complementary to in vitro experiments prior to testing new treatments. Animal models should make possible the validation of hypotheses and prove the safety and efficacy of new regenerating approaches using biomaterials, growth factors or stem cells. A review of the literature was carried out by using electronic databases (PubMed, ISI Web of Science). Numerous animal models in different species such as rats, hamsters, rabbits, ferrets, canines and primates have been used for modeling human periodontal diseases and treatments. However, both the anatomy and physiopathology of animals are different from those of humans, making difficult the evaluation of new therapies. Experimental models have been developed in order to reproduce major periodontal diseases (gingivitis, periodontitis), their pathogenesis and to investigate new surgical techniques. The aim of this review is to define the most pertinent animal models for periodontal research depending on the hypothesis and expected results.

Controlled release of bisphosphonate from a calcium phosphate biomaterial inhibits osteoclastic resorption in vitro

Calcium phosphate biomaterials such as calcium deficient apatite (CDA) have been contemplated as carrier for delivery of bisphosphonate in bone tissues. In the present work, we have investigated the in vitro biological properties of Zoledronate-loaded CDA. CDA was loaded with zoledronate according to a previously described coating process. 31P MAS NMR spectra demonstrated the effective loading of zoledronate onto CDA. Using 14C labeled zoledronate, we then demonstrated the in vitro release of zoledronate from CDA. In a first set of experiments, we confirmed that Zoledronate reduced the number of TRAP-, vitronectin receptor-, and F-actin ring-positive cells as well as the resorption activity of osteoclasts obtained from a total rabbit bone cell culture. Interestingly, Zoledronate-loaded CDA and its extractive solutions decreased the osteoclastic resorption. Finally, zoledronate-loaded CDA did not affect the viability and alkaline phosphatase activity of primary osteoblastic cells. These data demonstrate that CDA is effective for loading and release of zoledronate. The released zoledronate inhibited osteoclastic resorption without affecting osteoblasts. Our findings therefore suggest that such a drug delivery system would allow an increase in the efficiency of bisphosphonates by being locally available. Further experiments are now required to evaluate the in vivo antiresorptive activity of this concept.

Er:YAG Laser in the Clinical Management of Severe Peri-implantitis: A Case Report

Peri-implantitis is bacterial infections of peri-implant supporting tissues, involving the peri-implant bone. Several treatment protocols have been tested in clinical practice with variable efficacy. The clinical management of peri-implantitis aims for elimination of plaque and calculus, decontamination of the failing implant surface, and regeneration of lost bone tissue. Surface decontamination is an important part of all suggested treatments. This can be accomplished with the use of chemical agents (eg, chlorhexidine) or mechanical (eg, ultrasonic) or photonic (eg, laser) devices. In this report, we present a case of severe peri-implantitis that was successfully managed with a combined nonsurgical and surgical approach. Implant surface debridement/decontamination of the implant surface was achieved with an erbium-doped yttrium aluminium garnet (Er:YAG) laser device.

Gingival Biotype Assessement: Visual Inspection Relevance And Maxillary Versus Mandibular Comparison

Objective: This clinical study was aimed at evaluating the accuracy of gingival visual inspection procedures during clinical examination and determining whether differences existed between the maxillary and mandibular gingival biotypes. Materials and Methods: The study included 53 patients and 124 clinicians. The clinicians were asked to assign to each subject, using photographic documents, one of three biotypes: thin-scalloped, thick-scalloped, or thick-flat gingival biotype. A total of 19716 responses were collected for statistical analysis. Results: Identification accuracy of the gingival biotype and the intra-examiner repeatability presented poor highlighting of the limited relevance of visual inspection. In addition, the percent of agreement between classifications based on the global view of both the maxilla and mandible and the classification based on the individual mandibular or maxillary anterior teeth was not statistically significant. Conclusion: Based on the above results, it can be concluded that a simple visual inspection is not effective for the identification of gingival biotype. Furthermore, evidence suggests that a difference of biotype between the maxilla and the mandible in the same patient is conceivable. Therefore, orthodontic clinical examination should incorporate a reproducible method of determining the individualized gingival biotype for each group of teeth that will be moved.

Laser-Induced Fluorescence for Subgingival Calculus Detection: Scientific Rational and Clinical Application in Periodontology

OBJECTIVE To review the data available on the laser-induced calculus fluorescence phenomenon and the calculus detection devices as well as to determine the clinical relevance of using commercialized calculus detection devices in periodontal treatment. METHODS In vitro or in vivo English publications found on Medline. RESULTS In vitro and in vivo studies showed that the devices on the market had a satisfactory detection capacity. Very few studies demonstrated that the erbium:yttrium-aluminium-garnet (Er:YAG) laser debridement, when performed with automatic calculus detection, could lead to improvements at the clinical level, and the outcome was similar to that obtained with conventional treatments. CONCLUSIONS Although preliminary data were encouraging, there was a lack of scientific data concerning the calculus detection devices. Therefore, future studies are crucial for determining the clinical relevance of such equipment.

Clinical Outcomes After Nonsurgical Periodontal Therapy with an Er:YAG Laser Device: A Randomized Controlled Pilot Study

OBJECTIVE The purpose of this study was to compare the short-term effects of nonsurgical periodontal treatment with the short-term effects of Er:YAG laser debridement (ERL) and manual scaling and root planning (SRP) in nonsmoking patients with chronic periodontitis. METHODS Nineteen nonsmoking patients (mean age 60.7) with chronic generalized periodontitis were randomly treated with ERL or SRP in a split-mouth design. Clinical attachment level (CAL), periodontal pocket depth (PPD), and bleeding on probing (BOP) were recorded. Immediately after completion of the treatment procedure, patients used a visual analogue scale (VAS) to grade the degree of discomfort experienced during treatment. RESULTS Both groups showed significant reductions in their PPD, CAL, and BOP values 2 months after treatment. The sites treated with Er:YAG laser demonstrated mean PPD changes that varied from 5.00 ± 0.63 to 3.54 ± 0.83 mm, mean CAL changes that varied from 5.19 ± 0.69 to 3.86 ± 0.94 mm, and BOP changes that varied from 26.57 ± 12.54 to 13.17 ± 7.52 mm. Sites treated with manual SRP demonstrated mean PPD changes that varied from 4.91 ± 0.55 to 3.51 ± 0.98 mm, mean CAL changes that varied from 5.08 ± 0.59 to 3.95 ± 1.16 mm, and BOP values that varied from 24.81 ± 7.65 to 15.41 ± 6.32 mm. Comparison of the two techniques demonstrated the statistically significant superiority of Er:YAG only for the CAL scores (p<0.05). CONCLUSIONS Within the limits of this study, ERL may be posited as an alternative to mechanical treatment in the management of chronic periodontitis. In addition, ERL may be performed on patients who are sensitive to the use of injectable anesthetics. Future studies, with larger samples, are needed to determine the long-term clinical outcomes of ERL.

Assay of in vitro osteoclast activity on dentine, and synthetic calcium phosphate bone substitutes

Resorption of synthetic bone substitute materials is essential for the integration of these materials into the natural bone remodeling process. Osteoclast behavior in the presence of calcium phosphate bioceramics (CaPB) is partially understood, and a better understanding of the underlying mechanisms is expected to facilitate the development of new synthetic bone substitutes to improve bone regeneration. In the present study, our aim was to investigate osteoclastic resorption of various synthetic CaPB. We used neonatal total rabbit bone cells to generate osteoclasts. Osteoclast-generated resorption on dentine and multiple CaPB was investigated by quantifying the surface resorbed and measuring tartrate resistant acid phosphatase (TRAP) enzyme activity. In this study, we observed that osteoclastic cells responded in a different way to each substrate. Both dentine and CaPB were resorbed but the quantitative results for the surface resorbed and TRAP activity showed a specific response to each substrate and that increased mineral density seemed to inhibit osteoclast activity.

Effect of Sintering Process of HA/TCP Bioceramics on Microstructure, Dissolution, Cell Proliferation and Bone Ingrowth

The purpose of this study was to determine the effect of sintering conditions on microporosity of and cell proliferation and bone ingrowth on biphasic calcium phosphate (BCP) bioceramics. Discs were prepared from a calcium-deficient apatite preparation that upon sintering at 1050oC and above, results in a BCP with 60% hydroxyapatite (HA)/ 40% beta-tricalcium phosphate (β-TCP) ratio. The discs were divided into groups which were sintered under different conditions of heating rate (programmed vs. non-programmed) and temperature (1050°C vs. 1200°C). The discs were characterized in terms of composition (HA/β-TCP ratio), surface morphology, surface area, surface microporosity, per cent microporosity, and dissolution properties. The in vitro effect of sintering conditions on cell proliferation was determined using an established mouse fibroblast cell line (L929). Results demonstrated the following: (a) the HA/β-TCP ratio remained 60/40 regardless of sintering conditions; (b) the % microporosity, surface microporosity, surface area of the BCP and cell proliferation on the BCP significantly decreased with increasing sintering temperature, and (c) the extent of dissolution decreased with decreasing per cent microporosity. The in vivo study indicated no tissue adverse reaction and direct bone contact with the implant surface, confirming the biocompatibility of the BCP bioceramics. Resorption of the BCP and bone ingrowth was directly related to the sintering temperature: the higher the temperature, the lower the resorption and the bone ingrowth. Results of this study indicate that per cent microporosity of the BCP bioceramics affects its dissolution properties and cell response. The study demonstrates that optimum per cent microporosity elicits optimum cell response and should be considered to provide osteogenic/osteoinductive property to bioceramics.

Clinical Performance of Narrow-Diameter Titanium-Zirconium Implants: A Systematic Review

Purpose: Implant-supported prosthetic rehabilitations are in constant augmentation in everyday dental practice. This is largely due to increasing demand from patients for fixed or implant-stabilized prosthesis, although they are frequently reticent to complex preimplant bone augmentation surgeries, whenever bone volume is lacking. Narrow-diameter implants (NDI; ⩽3.5 mm) have been developed to offer relatively simple implant solutions in challenging bone-deficient sites. However, concerns regarding their mechanical properties have been raised. Special titanium-zirconium material (Ti-Zr), with superior mechanical resistance, compared with pure titanium alloys has been introduced into the market. The purpose of this systematic review was to determine the available data on clinical performance of Ti-Zr NDI. Materials and Methods: A literature search of all available clinical articles dealing with Ti-Zr NDI has been carried out. After including only prospective clinical trials, 14 papers were retrieved for thorough reviewing. Conclusion: Short-term results from preliminary clinical reports are quite promising, although the number of published studies and the follow-up periods are still insufficient to determine the real benefit of this hybrid material compared with titanium, especially when using NDI.

Le déplacement dentaire orthodontique : histologie, biologie et effets iatrogènes

Iatrogenic effects of orthodontic forces, in particular root resorption, are described in the literature. However, our knowledge on the risk of osseous defects induced by orthodontic treatment is still scarce. After an overview of histological and biological principles of orthodontically-induced tooth movement, this study focuses on the recent data concerning the occurrence and the treatment of bone resorption associated with orthodontic treatment.