Preprosthetic Surgery Research Articles

Calvarial Bone Grafts in Severe Maxillary Atrophy: Preprosthetic Surgery With Sedation

This is a technique report of cranial bone harvesting for severe maxillary atrophy without general anesthesia. A patient of Class VI by Cawood and Howell underwent 2 extensive bilateral sinus lifts with 5 cortical blocks with sedation only. The reconstruction made possible the placement of 8 Brånemark implants. The operation was performed as a day-hospital with a faster clinical and social recovery. This technique, by avoiding general anesthesia, makes calvarial bone grafting more comfortable for the patient and comparable to an intraoral harvest with less complications.

L'ostéotomie piézoélectrique : applications en chirurgie parodontale et implantaire

Reverse piezoelectricity is currently used in Dentistry for ultrasonic scaling devices. Using this technology, increasingly more powerful ultrasonic surgical lancets were developed within a few years, and these new tools have provided many practical solutions in oral and maxillofacial surgery. This article reviews the basic principles of piezosurgery, and its numerous clinical applications: in oral surgery (atraumatic extractions, wisdom teeth exposure, periapical cyst debridement, pre-prosthetic surgery), more specifically in periodontal (root planning and bone remodeling, crown lengthening) and implant surgery (sinus lift, removal of fractured implants, bone ridge augmentation, bone graft harvesting (crestal, retromolar, chin or tori)). The recent increased power of these instruments allows emphasizing a much wider range of clinical applications, extending to all surgical fields.

Treatment of Oligodontia With Endo-Osseous Fixtures

Clinical manifestations of oligodontia consist in agenesia of multiple teeth eventually with deciduous retained teeth, atrophy of alveolar ridge, aberrations of teeth dimension, and shape, with consequent aesthetic and functional defects. The first choice treatment is based on a team collaboration of maxillo-facial surgeon, orthodontist, and prosthodontist, and is conditioned by various clinical parameters as number and site of lacking teeth, age and dental development of patients, eventual alveolar ridge atrophy. Treatment planning should be individualized for each patient. In our experience, based on 8 consecutive patients at the end of dental growth affected by oligodontia, endo-osseous fixtures positioning was carried out in consideration of long-lasting stability and optimal aesthetical characteristics. In 5 patients rehabilitative preprosthetic surgical procedures were performed, consisting in 2 sinus lift with immediate positioning of 3 fixtures in both cases, 4 heterologous bone graft in postextractive sites with retained ankylotic deciduous teeth and 1 positioning of reabsorbable biomembrane. A temporary removable denture was positioned immediately after surgery in order to obtain a prompt aesthetical and psychosocial restore. Osseointegration ratio as observed at 8.5 years follow-up was analyzed according to surgical variables and differences in prosthetic rehabilitation (fixtures supporting single crown versus multiple crowns). Successful osteointegration was observed at 8.5 years mean follow-up in 58 fixtures, corresponding to a 96.6% ratio. Failure of integration was encountered in fixtures immediately positioned in postextractive sites having a mild grade of bone atrophy, supporting single crown. A rate of success of 100% was observed in cases of immediate or delayed positioning in postextractive or traditional sites.Fixtures positioning in patients affected by isolated oligodontia, without malformative syndromes, and at the end of dental development, is subject to the same recommendations for patients with lacking permanent teeth not caused by agenesia.

Langzeitergebnisse nach der Insertation von subperiostalen Gerüstimplantaten: Bericht über zwölf Patientenfälle

The subperiosteal dental implantation implant was orginally described in the 1940s. The inadequate long-term results of subperiosteal implants are in contrast to the excellent results documented for endosseus oral implants. Consequently, subperiosteal implants and other soft-tissue-anchored implants should not be used presently. The present report documented twelve patient cases with complications after treatment with subperiosteal implants. Typical complications of SI are implant exposure, inflammation, infection, fistula formation and implant mobility. After removing the SI severe atrophic bone was seen. The placement of osseointegrated oral implants was mostly not possible without autogenous bone grafting. The present report is in conclusion with other studies, that a regular control of patients with subperiosteal implants is necessary. Subperiosteal implants should definitely be removed, if continuous periods of complication occur. The complete oral rehabilitation requires further surgical treatment in the field of preprosthetic surgery.

Carbon dioxide lasers in maxillofacial surgery – our experience

Lasers have revolutionized every surgical specialty; none more so than the maxillofacial region. The use of lasers in maxillofacial surgery ranges from cosmetic resurfacing and hair removal to ablative oncosurgery. The carbon dioxide (CO2) laser is an excellent tool in the armamentarium of the maxillofacial surgeon. It can be used for resurfacing, coagulation of small vessels, pre-prosthetic surgery, excision of pathology, implant uncovering among other procedures with minimal morbidity and complications and a significant reduction in post-operative pain and inflammation. The paper presented is a collage of procedures routinely undertaken with CO2 laser with a discussion of actual and potential complications.

S311: Distraction Osteogenesis: Advanced Techniques for Bone Regeneration

The technique of distraction osteogenesis (DO) is becoming a routine part of the surgeon’s armamentarium. Recreating bone and soft tissue by the slow application of force to an osteotomy site, DO is a useful surgical technique. DO has been applied for the reconstruction of mandibular defects, maxillary and mandibular hypoplasia, craniofacial deformities, the reconstruction of a neo-condyle, sagittal split advancement and for pre-prosthetic surgery prior to implant placement. The concept of DO can also be applied to conventional oral and maxillofacial surgical techniques including hinge DO and rotational segmental DO for edentulous saddle deformities. DO can be utilized to widen narrow bony defects. As the literature has become replete with DO references, it is appropriate to review the surgical techniques of DO for evidence based outcomes. This course will review and present the spectrum of DO techniques including transport DO, DO for craniofacial/orthognathic/TMJ applications including airway as well as DO for implants/pre-prosthetic surgery, with an emphasis on recent advances in this surgical technique, with a team approach from two clinical perspectives.

Solvent-dehydrated fascia lata allograft for covering intraoral defects: Our experience

Mucosal defects in the oral cavity as a result of tumors, preprosthetic surgical procedure, or trauma are always a concern for surgeons. The aim of this study is to present our experience and discuss the advantages and problems arising with the use of solvent-dried human fascia lata allografts in oral mucosal defects, thus evaluating its clinical efficacy. Sixteen intraoral lesions were removed from 15 patients. The rehabilitation of the mucosal defects was achieved using solvent-dehydrated human fascia lata allografts. No graft rejection or infections were detected. The material was effective for enhancing the hemostasis, relieving the pain, and inducing rapid epithelization. The final result was excellent, even though in 2 cases complications were experienced. Hence, the use of the material proved to be reliable, practical, and safe.

Preprosthetic Periodontal Surgery in the Proximal Area With Modification of the COL Area: Results Following the Reestablishment of the Contact Point

Anatomic characteristics of interproximal areas are dependent on the anatomy, position, and proximal contact of adjacent teeth. The objective of this study was to investigate the influence of the reestablishment of the interproximal contact following the restorative alveolar interface (RAI) procedure on the interproximal gingival COL and formation of the interdental gingival papilla. Six mongrel dogs received bilateral apically positioned flaps, crown lengthening, and the RAI procedure on the maxillary fourth bicuspid and first molar. After 2 weeks, in a randomized manner, one side was prepared to receive metallic crowns and the opposite side remained as the control. The crowns were cemented at the 4-week postoperative period, and the dogs were sacrificed after another 4 weeks, totaling a period of 4 weeks with the full crowns in position and a total of 8 postoperative weeks. Histologic specimens were stained with hematoxylin and eosin and Mallory dyes. Sections 6 micro m thick were obtained in a bucco-lingual plane allowing ample visualization of the interproximal area. Clinical measurements revealed that, in the restored sides, four animals had complete fill of the interdental spaces with gingival papilla, whereas the other two dogs had a distance from the contact point to the tip of papilla varying from 0.02 to 0.021 mm. In the control group, papillae were totally reepithelialized with keratinized epithelium and a convex form. The epithelium completely covered the connective tissue and showed both epithelial projections and surface desquamation. On the test group, despite the presence of the prosthesis, the COL morphology modified by preprosthetic surgery was not altered, presenting a convex papilla with a triangular form and with a keratinized epithelium. Additional histologic characteristics were the same as found in the control group. Based on the results of this study, the reestablishment of the contact point does not revert what was obtained with the RAI procedure; the interproximal tissues remain convex and keratinized.

P.043 Dental implants inserted in the newly formed mandible reconstructed with autogenous bone using BMP-7

Augmentation procedures in the severely resorbed maxilla are standard techniques in preprosthetic surgery. Aim of the present study was to compare onlay bone grafting and sinus floor elevation with autogenous bone grafts in edentulous patients in terms of bone resorption of the posterior alveolar crest and implant survival in a 5-year longitudinal study. A total of 100 patients (53 female and 47 male patients) requiring augmentation using autogenous bone due to a severely resorbed maxillae were evaluated. The degree of resorption and bone quality were preoperatively estimated in panoramic radiographs according to Lekholm and Zarb. The overall 5-year success rate of implants placed after augmentation procedures in the posterior maxilla was 93.1%. Following onlay augmentations 215 out of 235 implant insertions were successful, i.e. a success rate of 91.5% was achieved. In the sinuslift group, 330 out 349 implants remained successful, i.e. a success rate of 94.6% was found. The difference between both groups was statistically significant at the end of the evaluation period. Bone resorption, measured as loss of total bone height in panoramic radiographs, was initially more pronounced following onlay augmentations (>20% after 12 months of observation). The degree of resorption decreased in the further course of the study. Lower resorption rates and a higher overall success rate were demonstrated for the sinus lift group.

P.049 The piezoelectric surgery for calvarial grafts in preprosthetic surgery

P.049 The piezoelectric surgery for calvarial grafts in preprosthetic surgery

P.063 The using of surgical lasers in the preprosthetic surgery

P.063 The using of surgical lasers in the preprosthetic surgery

S112: Distraction Osteogenesis: Advanced Techniques for Bone Regeneration

The technique of distraction osteogenesis (DO) is becoming a routine part of the surgeon’s armamentarium. Recreating bone and soft tissue by the slow application of force to an osteotomy site, DO is a useful surgical technique. DO has been applied for the reconstruction of mandibular defects, maxillary and mandibular hypoplasia, craniofacial deformities, the reconstruction of a neo-condyle, sagittal split advancement and for pre-prosthetic surgery prior to implant placement. The concept of DO can also be applied to conventional oral and maxillofacial surgical techniques including hinge DO and rotational segmental DO for edentulous saddle deformities.

Long-Term Culture of Human Gingival Keratinocyte Progenitor Cells by Down-regulation of 14-3-3σ

Human gingival keratinocytes in culture stop proliferating after a limited number of passages. This limitation is associated with a gradual depletion of the stem cell compartment of the cell population. Human skin keratinocytes have a three- to five-fold higher proliferation capacity under similar culture conditions, and previous studies indicated that stable down-regulation of the 14-3-3 sigma protein in these cultures prevents stem cell differentiation and generates immortal cell lines without the effects of tumorigenic transformation, e.g., genotypic alterations. In this report, we demonstrate the creation of an immortalized human gingival keratinocyte stem cell line by stable down-regulation of the 14-3-3 sigma protein. Keratinocyte cultures were generated from human subjects ranging from 17 to 92 years of age and retrovirally transduced with a 14-3-3 sigma antisense RNA expression construct. In contrast to the control cultures, which propagated for only 2-5 passages and 25-35 cell doublings, the 14-3-3 sigma-transduced cultures propagated for 11 passages and 110 cell doublings so far. The percentage of stem cells measured by clonal analysis, which gradually decreased in the control cultures, increased to a steady level of over 90% in the 14-3-3 sigma down-regulated culture. This gingival keratinocyte stem cell line and others, which can be generated using the same procedure, have the potential to be useful for studies on stem cell differentiation, for developing gene therapy procedures that target the gingival epithelium, as well as a stable platform for testing oral hygiene products and as potential material for preprosthetic surgery.

The usefulness of a multidisciplinary educational programme after breast cancer surgery: A prospective and comparative study

A system has been implemented using a commercial database management program and a microcomputer for computerising pre-prosthetic surgery. Using selection criteria, clinical records can be added, edited/deleted, searched for, displayed on screen, generate consultation summaries and operative discharge letters to the referring consultant, general medical and general dental practitioners together with a synopsis of the clinical assessment and surgical admission. Surgical audit may be conducted on the records. This progam will hold 30 000 clinical records. Such a system is beneficial for personal and departmental audit, epidemiological studies and research into the prevalence of surgical treatment and postoperative morbidity.

Prosthodontic rehabilitation after traumatic tooth and bone loss: A clinical report

Traumatic injuries from motor vehicle accidents may cause anatomic deficiencies in soft and hard tissues. Successful treatment of patients with such deficiencies may include preprosthetic surgery using osseointegrated implants to increase prosthesis retention and stability. This article describes the treatment of a motor vehicle accident victim whose anterior teeth and supporting tissues were lost.

Dental implants – pertinent papers 2002–2003: A personal view

T u c t s r o o a i i s when custom-made bridges and crowns fitted at the time of placement implants is the norm. This paper stresses the importance of careful planning and notes failures associated with bruxism; this harks back to similar warnings in earlier papers about implants. The benefits of accelerated care for patients are clear; we are, however, reminded that this is associated with a slightly higher risk of failure than the traditional approach.

Onlay augmentation versus sinuslift procedure in the treatment of the severely resorbed maxilla: a 5-year comparative longitudinal study

Augmentation procedures in the severely resorbed maxilla are standard techniques in preprosthetic surgery. Aim of the present study was to compare onlay bone grafting and sinus floor elevation with autogenous bone grafts in edentulous patients in terms of bone resorption of the posterior alveolar crest and implant survival in a 5-year longitudinal study. A total of 100 patients (53 female and 47 male patients) requiring augmentation using autogenous bone due to a severely resorbed maxillae were evaluated. The degree of resorption and bone quality were preoperatively estimated in panoramic radiographs according to Lekholm and Zarb. The overall 5-year success rate of implants placed after augmentation procedures in the posterior maxilla was 93.1%. Following onlay augmentations 215 out of 235 implant insertions were successful, i.e. a success rate of 91.5% was achieved. In the sinuslift group, 330 out 349 implants remained successful, i.e. a success rate of 94.6% was found. The difference between both groups was statistically significant at the end of the evaluation period. Bone resorption, measured as loss of total bone height in panoramic radiographs, was initially more pronounced following onlay augmentations (>20% after 12 months of observation). The degree of resorption decreased in the further course of the study. Lower resorption rates and a higher overall success rate were demonstrated for the sinus lift group.

The use of cone beam CT in cranio-maxillofacial surgery

The cone beam CT (digital volume tomography) is a new imaging technique. The main advantages of DVT, compared with the standard CT scan, are the lower radiation dose and the lower cost. With the use of a special software program, the primary reconstruction of the raw images is carried out and axial views performed as the basis for secondary reconstructions. The DVT is used in our department for data acquisition in trauma patients, imaging of intraosseous and odontogenic tumors, diseases of the maxillary sinus, expansion of cysts in the maxillofacial area, relation of impacted teeth to anatomical structures and mainly in the field of preprosthetic surgery and oral implantology. A series of cases will be presented: preoperative and postoperative views of trauma patients, giant-cell granuloma of the mandible, a cyst in the maxillary sinus, the close relation of an impacted wisdom tooth with the inferior alveolar nerve and many cases of preimplantological planning. The reconstruction of the bony tissue is of higher quality compared to conventional X-ray examination. Furthermore, the radiation exposure of the patient during the DVT examination is approximately 20% of the dosage, which has to be accepted performing a standard CT examination in the same area.

A metabolically active dermal replacement (Dermagraft) for vestibuloplasty

This article describes the use of tissue-engineered dermal replacement in the vestibular extension instead of palatal donor tissue or (split-thickness) skin graft. In three patients the living human-derived fibroblast skin substitute (Dermagraft) was implanted on the wound surface after mucogingival junction and supraperiosteal dissection. Following application of Dermagraft, epithelial closure starting from the resection margins of the defect was observed, obviating further surgical treatment. Vestibular depth was increased and no scarring or frena occurred. Tissue-engineered dermal replacement consisting of living human fibroblasts appears to be a useful substitute for autogenous grafts in pre-prosthetic surgery, offering the advantages of unlimited availability, good colour match and no donor site morbidity.

Midface deficiencies—Options for preprosthetic orthognathic surgery

Midface deficiencies—Options for preprosthetic orthognathic surgery