Serge Dibart

Traitements orthodontiques accélérés par piézocision : une alternative mini-invasive aux corticotomies alvéolaires

An increasing number of adult patients are seeking orthodontic treatment and a short treatment time has become a recurring request. To meet their expectations, a number of surgical techniques have been developed to accelerate orthodontic tooth movement. However, these have been found to be quite invasive. We are introducing here a new, minimally invasive flapless procedure, combining micro incisions, piezoelectric incisions and selective tunneling that allows for hard- or soft-tissue grafting. Combined with a proper treatment planning and a good understanding of the biological events involved, this novel technique can locally manipulate alveolar bone metabolism in order to obtain rapid and stable orthodontic results. Piezocision allows for rapid correction of severe malocclusions without the drawbacks of traumatic conventional corticotomy procedures.

Children, adolescents and periodontal diseases

OBJECTIVES This manuscript attempts to critically review current literature regarding the natural history, aetiology and pathogenesis of the common periodontal diseases to affect children and adolescents. The logic behind the emergence of a new classification in the early 1990s is explained and potential problems with the interpretation of such systems outlined. DATA SOURCES The manuscript focuses upon recent developments, reported in the international periodontal literature, aimed at unraveling the molecular basis for this group of diseases. The concept of one disease type progressing with time to another disease within the same individual is discussed, and early data presented that indicate the possibility of microbial transmission from deciduous to permanent dentitions within a subject. CONCLUSIONS It is concluded that differing classification systems for adolescent and childhood periodontal diseases may lead to confusion within the dental profession, unless the clinical and molecular basis for such diseases is fully understood. Further advances in basic research using molecular biology tools should assist in our understanding of the aetiopathology at a molecular level and hopefully lead to the development of new treatment strategies.

Clinical Evaluation of Single-Stage Advanced Versus Rotated Flaps in the Treatment of Gingival Recessions

BACKGROUND Several procedures have been reported for the surgical correction of gingival recession (GR), including the laterally positioned flap (LPF) and the coronally advanced flap (CAF), performed as single- or two-stage procedures without or with, respectively, the preceding placement and healing of a free gingival graft. The objective of the present report was to compare the efficacy of single-stage LPF and CAF techniques in the treatment of localized maxillary GR defects. METHODS Thirty-six patients, 10 men and 26 women, with average age of 34 + or - 9 years with Miller Class I GR defects were randomly assigned to be treated by either a CAF (n = 18) or LPF (n = 18). Clinical parameters, including recession height, the width of keratinized tissue (WKT), probing depth, and vertical clinical attachment level were assessed at the mid-buccal site. Visual plaque score and bleeding on probing were also assessed dichotomously. Clinical recordings were performed at baseline and 6 months later. Intermeasurements differences were analyzed with a chi-square or a Wilcoxon test, with significance set at alpha<0.05. RESULTS Both flap designs were effective in treating recession defects resulting in similar improvements for percentage of root coverage, frequency of complete root coverage, and gain in clinical attachment level. The LPF resulted in significantly more gains in WKT than the CAF. CONCLUSION The results obtained by CAF in the treatment of Miller Class I maxillary GR are clinically similar to the LPF albeit with more limited gains in WKT.

A clinical comparison of two flap designs for coronal advancement of the gingival margin: semilunar versus coronally advanced flap

BACKGROUND The semilunar incision was introduced in oral surgery more than a century ago. The semilunar coronally re-positioned flap (SLCRF) is one of the variants of this procedure; however, no previous controlled clinical study has evaluated the SLCRF performed as originally described. The objective of the present study was to compare the clinical outcomes of the SLCRF and coronally advanced flap (CAF) procedure in the treatment of maxillary Miller class I recession (GR) defects. MATERIALS AND METHODS Twenty-two patients, with 22 contra-lateral Miller class I GR defects, were randomly assigned to CAF or SLCRF. Clinical parameters assessed included recession height, width of keratinized tissue, probing depth, vertical clinical attachment level, visual plaque score and bleeding on probing. Clinical recordings were performed at baseline and 6 months later. Inter-measurements differences were analysed with a chi(2) or a paired t-test, with significance set at alpha<0.05. RESULTS Both flap designs were effective in obtaining and maintaining a coronal displacement of the gingival margin. The CAF resulted in clinical improvements significantly better than SLCRF for percentage of root coverage (RC), frequency of complete RC and gain in clinical attachment level. RC obtained in the immediate post-surgical period of SLCRF-treated sites was not maintained throughout the subsequent evaluations. CONCLUSION RC is significantly better with CAF compared with the original SLCRF technique in the treatment of shallow maxillary Miller class I GR defects.

Tissue response during Piezocision-assisted tooth movement: a histological study in rats.

OBJECTIVES Piezocision is a novel, minimally invasive technique combining micro-incisions and decortications made by a piezotome in order to enhance the rate of orthodontic tooth movement. The combined technique allows simultaneous hard and/or soft tissue grafting via selective tunnelling to correct gingival recessions or bone deficiencies. The present study was designed to evaluate the effects of Piezocision on bone with or without tooth movement on a rat model. MATERIALS AND METHODS Ninety-four Sprague-Dawley rats were divided into four groups: no treatment (n = 3), TM (tooth movement alone; n = 21), PS (Piezocision alone; n = 35), and PS + TM (Piezocision and tooth movement; n = 35). In each group, seven time points were studied: 1, 3, 7, 14, 28, 42, and 56 days. After sacrifice, the maxillae were removed, defleshed, stained with haematoxylin and eosin for morphometric analyses and tartrate-resistant acid phosphatase for osteoclastic activity. RESULTS Three days after the surgery, the bone content decreased significantly in the PS and PS + TM groups compared to baseline (P < 0.01) and the TM group (P < 0.05). This trend continued until Day 28 and was particularly evident in the PS + TM group. At Day 56, alveolar bone returned to its baseline levels in all groups. Osteoclastic activity followed similar change pattern found in the amount of bone, suggesting a strong role for the coupling of the resorptive and formative turnover of the bone. Osteoclastic activity increased as soon as Day 1 in the PS (29.0±3.0, P < 0.05) and PS + TM groups (39.0±6.0, P < 0.01) compared to baseline (22.0±4.0). The highest level of osteoclastic activity in TM group was observed at 3 days (64.3±8.0, P < 0.01) with a steady decrease thereafter. The Piezocision-induced osteoclastic activity showed a steady increase up to 7 days in both PS (39.0±7.0, P < 0.01) and PS + TM (51.8±7.0, P < 0.01) groups and decreased thereafter until Day 56. CONCLUSIONS Within the limitations of our study (number of animals, duration in time, and limited data on the anabolic activity), our preliminary results suggest that Piezocision-facilitated orthodontic tooth movement increases the rate of movement of the teeth undergoing orthodontic treatment through the coupled remodelling of the alveolar bone. This process is initiated by the osteoclastic activity following surgery and extended via the synergistic relationship between Piezocision and tooth movement.

Accélération du mouvement dentaire orthodontique suite à une décortication alvéolaire sélective : justification biologique et résultat d’une technique novatrice d’ingénierie tissulaire

Resume Suite a une decortication alveolaire selective – definie comme la scarification chirurgicale du cortex alveolaire – des malocclusions severes peuvent etre traitees orthodontiquement en six mois. Combinee avec une greffe osseuse, cette technique multiplie de facon significative les possibilites de traitement pour corriger, avec des resultats cliniques stables, les cas d’encombrement severe de l’arcade ou de problemes squelettiques limites. La biologie du mouvement dentaire rapide apres decortication alveolaire selective se traduit par une diminution passagere de la densite osseuse, ce qui engendre une zone localisee de moindre resistance. Les etudes sur animaux ont demontre que la demineralisation-remineralisation (osteopenie) constitue le fondement de l’orthodontie rapide et il a ete emis l’hypothese que la stabilite du resultat orthodontique est due a une acceleration du renouvellement tissulaire ainsi qu’a une augmentation de l’epaisseur de l’os cortical a la suite de la greffe. Un plan de traitement bien etabli associe a une bonne comprehension de l’action biologique sous-jacente permet une manipulation locale du metabolisme de l’os alveolaire afin d’obtenir des resultats a la fois rapides et stables. Actuellement, cette technique novatrice d’ingenierie tissulaire offre au clinicien un nouvel outil pour le traitement des adultes les plus exigeants.

Computer-guided surgery using the piezocision technique.

A variety of surgical procedures have been developed to accelerate orthodontic treatment of adult patients seeking to enhance their smiles or masticatory function. While most of these techniques are invasive, the minimally invasive piezocision technique reduces trauma by combining microincisions and localized piezoelectric bone surgery. A method for combining piezocision with the use of computed tomography is presented here. By creating a three-dimensional model of the arch, the depth and location of the corticotomies can be precisely planned, and a surgical guide can be fabricated and used to prevent any damage to the dental roots.

Effect of Corticotomies with Different Instruments on Cranial Bone Biology Using an Ex Vivo Calvarial Bone Organ Culture Model System.

Different corticotomy surgical procedures have been developed to shorten orthodontic treatment times by stimulating bone remodeling. Although all corticotomy procedures involve physical injury to the bone, the clinical outcomes can vary. Using an ex vivo calvarial bone organ culture model system, the authors evaluated the biologic response of bone to different corticotomies. Bone injuries were generated in 276 calvaria dissected from 5- to 7-day-old neonatal mice using a piezoelectric knife, a bur, and a handheld screw device. The responses were evaluated using chemical, biochemical, and global histomorphometric analyses. Injuries generated by the three approaches induced varying degrees of bone remodeling activities; however, the piezoelectric knife led to the most extensive impact in both bone resorption and formation models.

Bone microenvironment-mediated resistance of cancer cells to bisphosphonates and impact on bone osteocytes/stem cells

Anti-resorptive bisphosphonates (BPs) have been clinically used to prevent cancer-bone metastasis and cancer-induced bone pathologies despite the fact that the phenotypic response of the cancer-bone interactions to BP exposure is “uncharted territory”. This study offers unique insights into the interplay between cancer stem cells and osteocytes/osteoblasts and mesenchymal stem cells using a three-dimensional (3D) live cancer-bone interactive model. We provide extraordinary cryptic details of the biological events that occur as a result of alendronate (ALN) treatment using 3D live cancer-bone model systems under specific bone remodeling stages. While cancer cells are susceptible to BP treatment in the absence of bone, they are totally unaffected in the presence of bone. Cancer cells colonize live bone irrespective of whether the bone is committed to bone resorption or formation and hence, cancer-bone metastasis/interactions are though to be “independent of bone remodeling stages”. In our 3D live bone model systems, ALN inhibited bone resorption at the osteoclast differentiation level through effects of mineral-bound ALN on osteocytes and osteoblasts. The mineral-bound ALN rendered bone incapable of osteoblast differentiation, while cancer cells colonize the bone with striking morphological adaptations which led to a conclusion that a direct anti-cancer effect of BPs in a “live or in vivo” bone microenvironment is implausible. The above studies were complemented with mass spectrometric analysis of the media from cancer-bone organ cultures in the absence and presence of ALN. The mineral-bound ALN impacts the bone organs by limiting transformation of mesenchymal stem cells to osteoblasts and leads to diminished endosteal cell population and degenerated osteocytes within the mineralized bone matrix.

Platelet-Derived Growth Factor-Mediated Guided Bone Regeneration in Immediate Implant Placement in Molar Sites with Buccal Bone Defects.

This study compared the clinical outcomes of recombinant human platelet-derived growth factor BB and beta-tricalcium phosphate (rhPDGF-BB/βTCP) with guided bone regeneration (GBR) in immediate implant placement in molar extraction sockets with buccal bone defects versus conventional implant placement. Twenty-eight implants were placed in fourteen patients. Clinical and radiographic evaluations assessed peri-implant soft and hard tissue parameters after 12 months. No implants were lost during the 1-year observation period, yielding a survival rate of 100%. Similar clinical and radiographic parameters were observed for both treatment groups. Use of rhPDGF-BB/βTCP and GBR in immediate implants in molars was as successful as conventional implant placement in fully healed extraction sites.