Intermediate bone grafting of alveolar clefts

During the five year period 1980 to 1985 bone grafting was performed in 37 cleft patients before the eruption of the canine tooth (group IBG) and in 30 patients after the eruption of the canine tooth (group SGB). The initial healing was more favourable in the IBG group. In 72.5% of the clefts oro-nasal fistulae were present preoperatively. In all cases the fistulae were successfully closed. In the IBG group with orthodontic closure of the gap in the dental arch the interdental bone height in the grafted area was more than 75% of normal bone height in all clefts. In group SBG this situation was found in only 66% of the bone-grafted areas. There seems to be a clear relation between the age or the developmental stage of the canine tooth on the one hand and the possibility of orthodontic closure of the gap in the dental arch and good interdental bone height on the other hand. This also leads to the suggestion that if bone grafting to the alveolar cleft is required the operation should be performed before the eruption of the canine tooth on the cleft side.     

Biomechanik der Jarabak-Technik

Zusammenfassung DieJarabak-light-wire-Technik beruht auf vier Prinzipien: 1. richtungsfixierte Kraftkontrolle, 2. leichte biologische Kräfte, 3. schnelle Behandlung und 4. Stabilität. Durch den Einbau vorprogrammierter Mechanismen in die Brackets wird die Kraftkontrolle während orthodontischer Zahnbewegungen vereinfacht. Die Anwendung leichter kontinuierlicher Kräfte führt zu schnelleren ossären Reorganisationsprozessen und verringert die Gefahr parodontaler Schädigung. Das Konzept derJarabak-light-wire-Technik sowie die abschließende Anwendung eines speziellen Positioners (=rubber finishing appliance) ermöglichen eine maximale funktionelle Einstellung der Okklusion, die für die permanente Stabilität der Behandlungsergebnisse notwendig ist.

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Summary TheJarabak light-wire philosophy is based on four principles: 1. directional controlled force; 2. light biological forces; 3. rapid treatment and 4. stability. By using programmed brackets, force control during tooth movement is simplified. The use of light continuous forces leads to quicker bony remodelling and reduces the likelihood of periodontal trauma.Jarabak's light-wire technique combined with the rubber finishing appliance provide the adjustment necessary for the stability of the treatment result.

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Résumé La techniqueJarabak-light-wire repose sur 4 principes, à savoir: 1. direction déterminée des forces, 2. forces biologiques légères, 3. traitement rapide et 4. stabilité. Les mécanismes étant préprogrammés dans les brackets, le contrôle des forces est simplifié durant les mouvements orthodontiques. Le recours à des forces continues peu importantes favorise le processus de remodelage osseux rapide et prévient le risque de lésion paradontale. La conception de la techniqueJarabak-light-wire ainsi que l'utilisation finale d'un positioner spécial (=rubber finishing appliance) permet un ajustage fonctionnel maximal de l'occlusion nécessaire à la stabilité permanente des résultats du traitement.

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Übersetzung: Dr. C. A.Landferman, Kieferorthopädische Abteilung des Klinikums Albert-Ludwigs-Universität, Hugstetterstraße 55, 7800 Freiburg/Br.     

Prosthodontic management of the hydroxylapatite denture patient: a preliminary report

A 4-year study and evaluation of nonresorbable hydroxylapatite to augment different alveolar ridges has been reported. The technique used resulted in improved contour, height, and width of the alveolar ridge. It was found that denture comfort improved with ridge augmentation as this allowed improved stability, support, and preservation of the ridge. Patient satisfaction was correlated to both surgical and prosthodontic success with the use of hydroxylapatite. The state and health of the tissues were found to be improved with the use of hydroxylapatite or hydroxylapatite and bone marrow. The prosthetic and surgical procedures were found to be easier to perform, and they produced more permanent and superior results than those previously experienced with only bone grafts and other alloplasts.     

Maxillary sinus floor grafting with beta-tricalcium phosphate in humans: density and microarchitecture of the newly formed bone

OBJECTIVES: Graft insertion can effectively enhance the regeneration of debilitated bone. The effects of an alloplastic bone-replacing material, beta-tricalcium phosphate (Cerasorb), and of autogenous bone graft were compared. MATERIALS AND METHODS: In 17 edentulous patients, the maxillary sinus floor was extremely atrophied to such an extent that implant placement was impossible. The Schneiderian membrane was surgically elevated bilaterally by insertion of Cerasorb (experimental side) and autogenous bone graft (control side). After surgery, the recovery was followed clinically and radiologically. After 6 months, 68 bone cylinders were excised from the grafted areas and implants were inserted into their places. The bone samples were embedded into resin, and the osteointegration of the grafts was studied histologically. Trabecular bone volume (TBV) and trabecular bone pattern factor (TBPf) were quantified by histomorphometry. RESULTS: Cerasorb proved to be an effective bone-replacing material with osteoconductivity; it was capable of gradual disintegration, thereby providing space for the regenerating bone. The new bone density was not significantly different on the experimental and control sides (32.4+/-10.9% and 34.7+/-11.9%, respectively). However, the graft biodegradation was significantly slower on the experimental side than the control side. The TBPf value was lower on the control side than on the experimental side (-0.53+/-1.7 and -0.11+/-1.4 mm(-1), respectively), but this difference was not significant. CONCLUSIONS: Six months after insertion of the grafts, the bone of the augmented sinus floor was strong and suitable for anchorage of dental implants, irrespective of whether autogenous bone or Cerasorb particles had been applied.     

Cell-based bone reconstruction therapies--cell sources

Over the last few decades, reconstructive surgery has shifted from a resection-oriented approach toward strategies focusing on repair and regeneration of tissues. As the main aim of maxillofacial reconstruction has been the restoration of bone form and function, surgeons used artificial tissue substitutes in the early decades of bone reconstruction. These artificial materials significantly improved the ability of surgeons to restore the form and, to some extent, the function of defective bones. Despite the fact that every artificial material has specific disadvantages, the use of biomaterials is a common treatment option in clinical practice even today. Due to the more detailed understanding that exists concerning transplantation of cells and tissues, autogenous grafts are the second mainstay in clinical practice. However, the main disadvantage of using autogenous grafts is donor site morbidity and donor shortage. Research is currently in progress into the use of cell-based approaches in reconstructive surgery, since cells are the driving elements for all repair and regeneration processes. Various cell populations have been reported on in the relevant literature. These cells can be classified according to differentiation capacity and the tissue from which they originated. In this review, unrestricted cells, multipotential progenitor cells, determined cells, and genetically modified cells are described systematically, and their advantages as well as limitations are discussed. (More than 50 references.)     

Quantitative and qualitative comparison of the maxillary bone regeneration after beta-tricalcium phosphate and autogenous bone implantation

Graft insertion can effectively enhance the regeneration of debilitated bone. The effects of an alloplastic bone-replacing material, beta-tricalcium phosphate (Cerasorb), and of autogenous bone graft were compared. In 17 edentulous patients, the maxillary sinus floor was extremely atrophied to such an extent that implant placement was impossible. The Schneiderian membrane was surgically elevated bilaterally by insertion of Cerasorb (experimental side) and autogenous bone graft (control side). After surgery, the recovery was followed clinically and radiologically. After 6 months, 68 bone cylinders were excised from the grafted areas and implants were inserted into their places. The bone samples were embedded into resin, and the osteointegration of the grafts was studied histologically. Trabecular bone volume (TBV) and trabecular bone pattern factor (TBPf) were quantified by histomorphometry. Cerasorb proved to be an effective bone-replacing material with osteoconductivity; it was capable of gradual disintegration, thereby providing space for the regenerating bone. The new bone density was not significantly different on the experimental and control sides (32.4 +/- 10.9% and 34.7 +/- 11.9%, respectively). However, the graft biodegradation was significantly slower on the experimental side than on the control side. The TBPf value was lower on the control side than on the experimental side (-0.53 +/- 1.7 mm(-1) and -0.11 +/- 1.4 mm(-1), respectively); but this difference was not significant. Six months after insertion of the grafts, the bone of the augmented sinus floor was strong and suitable for anchorage of dental implants, irrespective of whether autogenous bone or Cerasorb particles had been applied.     

The combined use of two endosteal implants and iliac crest onlay grafts in the severely atrophic mandible by a modified surgical approach

Seventeen patients, who received an iliac crest onlay bone graft augmentation to their severely atrophic mandible with simultaneous placement of two endosteal implants by a modified surgical approach, were studied retrospectively. Follow-up ranged from 0.5 to 7.9 years after implant loading with an average follow-up of 4.3 years. Frequency of wound dehiscences and other postoperative complications, the extend of resorption of the initial graft, and the implant success rate were assessed. Two patients, who had a previous history of preprosthetic and implantological procedures at the surgical site, developed a serious wound dehiscence with loss of two implants in one patient and need for antibiotic treatment and sequestrectomy in the other patient. One implant was lost in two other patients with a negative surgical history, resulting in an implant success rate of 88.2%. The average resorption at the last follow up visit was 15% of the initial graft. Damage of the mental nerve was seen in 14.7% of nerves. Our preliminary data indicate that the procedure presented provides a reliable and predictable method for the construction of an implant-bearing overdenture in patients with a severely atrophic mandible. This one-step procedure can not be recommended for patients with a history of surgery in the anterior mandible.     

Ramus graft and 1-stage implant placement: a case report

Althougth hard-tissue grafting protocols have typically recommended a 6-month healing period before placement of any dental implants at the graft site, it may be possible to secure an onlay graft to a wide but shallow alveolar ridge using implants that are then submerged and allowed to osseointegrate. This approach has the advantage of expediting treatment and making it less traumatic for the patient. A case is described in which a portion of an edentulous mandible was augmented with ramus bone secured with 2 dental implants.     

Protection of the lip from the activator arm of maxillary distractors

The long spring-loaded distractor arms of maxillary distraction devices can cause pain and ulceration of the upper lip. We describe a simple method to relieve the tension and discomfort on the soft tissues using Silastic tubing.     

Remineralization of deep enamel dentine caries lesions

Enamel remineralization is generally studied in superficial (up to 100 mum) lesions, but in vivo caries lesions may be tenfold deeper. This article addresses the question whether deep lesions, and extending into dentine, can be remineralized under optimal conditions and if this process is influenced by agents affecting calcium phosphate precipitation and dissolution. Lesions through enamel into dentine were first formed in thin sections and then continuously remineralized for periods up to 200 days. With longitudinal assessment by transversal microradiography it was showed that remineralization throughout the depth of the lesion and into the dentine was possible, although this process is very slow. Fluoride and bisphosphonate treatments affected mainly the deposition in the outer enamel. Although it was assumed that this would affect the diffusion of ions to deeper layers, the treatments had no impact on remineralization in the inner enamel or dentinal parts of the lesions. These findings are discussed with relevant theoretical considerations, and in their possible clinical implications.