Design, maintenance and biomechanical considerations in implant placement

Successful treatment using implants involves careful consideration of fixture placement and prosthesis design if the biomechanical conditions are to be optimized. These parameters may be related to the implant/tissue interface at the individual fixture level, and thence to the relationship between the components of a prosthesis. The influence of the nature and magnitude of occlusal forces can also be significant and should be carefully assessed before placement.     

Implant placement: surgical techniques and considerations

Successful implant surgery largely depends on good planning and meticulous technique. The former requires an appreciation of the restorative requirements and visualization of the desired end result. This may be easier for the clinician who is delivering both aspects of treatment, but in other circumstances requires close collaboration between prosthodontist and surgeon. This paper focuses on the surgical techniques involved in implant surgery, because successful osseointegration is achievable only with careful surgical preparation.     

Treatment planning and surgical considerations for placement of wide-body implants

Partially edentulous implant treatment has evolved from using a standard diameter fixture for every tooth site to selection of the implant diameter according to the surgical demands, space available, and the dimension of the final prosthetic tooth. The advantages are functional, improved emergence profiles for esthetics, and optimal contours for oral hygiene maintenance. This article reviews presurgical treatment planning for wide-diameter implants.     

Complications of motility peg placement for the hydroxyapatite orbital implant

PURPOSE: The hydroxyapatite implant is an ocular motility implant designed to provide natural movement of the artificial eye. The movement of the prosthesis is maximized when the implant is coupled to the prosthesis via a peg. The purpose of this study is to determine the complications of the hydroxyapatite motility peg and the factors related to those complications. DESIGN: Retrospective review of 47 cases over 5 years. METHODS: A retrospective review was performed on all cases of hydroxyapatite motility peg placement. The technique of hydroxyapatite and peg placement, follow-up details, and complications of the peg were recorded. RESULTS: The complications of peg placement included peg extrusion in 26% (12 of 47), nonspecific conjunctivitis in 6% (3 of 47), audible click in 6% (3 of 47), temporary excessive conjunctival edema in 4% (2 of 47), and temporary excessive postoperative pain in 4% (2 of 47). There were no cases of infection, persistent pain, persistent edema, or discharge at peg site. The median time interval from peg placement to extrusion was 16 months (range, 1-52 months). The only statistically significant factor related to peg extrusion was age over 50 years (P = 0.04). There was a trend toward peg extrusion with use of a nonsleeved peg (versus sleeved peg) (P = 0.10). The extrusion rate was 32% (12 of 38) for nonsleeved pegs and 0% (0 of 9) for sleeved pegs. Factors unrelated to peg extrusion were patient sex, prior ocular surgery or radiotherapy, presence of giant papillary conjunctivitis, time interval from enucleation to peg placement, and degree of implant vascularization on magnetic resonance imaging. Of the 12 nonsleeved pegs that extruded, a sleeved peg system was subsequently successfully placed in 5 patients, a nonsleeved peg in 1 patient, and 6 patients remained without a peg system. CONCLUSIONS: Hydroxyapatite motility pegs have relatively few complications except for extrusion. The rate of extrusion can be minimized by employing a sleeved peg rather than a nonsleeved peg system.     

Mechanical considerations for the implant tooth-supported fixed partial denture

The implant tooth-supported fixed partial denture presents a biomechanical design problem, because the implant is rigidly fixed within the alveolus, and the tooth is surrounded by a periodontal ligament that allows movement. Nonrigid fixed partial denture designs are advocated by some dentists as a method of compensating for this differential movement. Rigid fixed partial denture designs, however, are advocated by many clinicians. Studies have failed to show the advantage of one design over the other. This study developed an in vitro method for testing such prosthesis designs and measured movement of a natural tooth abutment during simulated function. The movement of the natural tooth abutment was not found to change substantially with the fixed partial denture designs tested.     

Anesthetic considerations for the pediatric plastic surgical patient

An understanding of the anesthesiologist's concerns during pediatric plastic surgical procedures can facilitate the coordination of efforts between the multiple services involved in the care of these children. Prior to surgery, the child's history is obtained and physical examination is performed. The condition of the airway is the primary concern. Preoperative medication is usually given by oral routes to avoid injections. Induction intubation, maintenance, and emergence are discussed. Specific postanesthesia care is described. Special precautions are given for children having surgical repair of craniofacial anomalies. Cleft lip and palate and mandibular advancement are described.     

Single-stage surgery for implant placement: a retrospective study

Single-stage implant placement surgery offers patients a number of advantages. These include reduced cost and time commitments and greater comfort, function, and convenience. This article reports on the results of using a single-stage technique with 58 patients fitted with 240 implants. No implant failures were detected in any patients prior to the final attachment of a Dolder bar. Among the 27 patients and the 125 implants followed for a longer period of time, 99.2% exhibited no signs of implant mobility or pain. Indicators of gingival health and oral hygiene ranged in quality from acceptable to ideal.     

Reconstruction of alveolar defects before implant placement

Guided bone regeneration and bone grafting have been used to reconstruct defective alveolar ridges in preparation for implant placement. This phase of implant treatment is critical to a successful overall result. Remarkable advances that have occurred in techniques and materials enable us to place and restore implants in cases where previously it was not feasible. Three case reports are presented to illustrate successful management of different alveolar defects.     

Anterior aesthetic considerations for the placement and restoration of nonsubmerged endosseous implants

Nonsubmerged endosseous dental implants should be considered when planning optimal anterior implant rehabilitation. Detailed diagnostic records are a necessity, along with preoperative and preprosthetic treatment plans that are designed to address the unique challenges of anterior restorations. This paper discusses these concerns and presents two case reports which utilize some of the techniques that can be incorporated into achieving predictable anterior aesthetic rehabilitation using a single-stage implant. The learning objective of this article is to familiarize the reader with those challenges and techniques.     

The use of osteotomes for sinus augmentation at the time of implant placement

The placement of endosseous dental implants is often hampered by the loss of alveolar bone. In the posterior maxilla, the presence of the maxillary sinus and less-dense bone present additional obstacles to successful implant placement. Existing methods of subantral augmentation require extensive surgical manipulation, often including a second surgical site for harvesting autogenous bone. The development of surgical osteotomes has facilitated the placement of implants in areas of minimal alveolar bone height in the posterior maxilla. This article describes the osteotome technique for sinus augmentation at the time of implant placement and presents a short-term evaluation of 34 implants placed in 18 patients.     

Simplified guide for precise implant placement: a technical note

Loss of heterozygosity (LOH) at chromosome band 10q23 occurs frequently in a wide variety of human tumors. A recently identified candidate tumor suppressor gene, PTEN located on 10q23, is mutated in multiple advanced cancers. To explore whether PTEN is associated with human squamous cell carcinoma of the head and neck (SCCHN), DNAs from both normal muscle and tumor tissue in 19 SCCHN were used for detecting LOH at chromosome 10q23 and mutational analysis of PTEN by direct polymerase chain reaction (PCR)-DNA sequencing. LOH at 10q23 was identified in 6/15 SCCHN. Mutation of PTEN was identified in 3/19 SCCHN. Of these 3 patients, 2 had stage IV disease; the third patient, with recurrent, metastatic and stage III disease, showed a 36 bp germline heterozygous deletion within intron 7. Furthermore, a missense mutation at codon 501 (TCT --> TTT: Ser --> Phe) in exon 8 was also found in tumor from the same patient. Our results suggest that PTEN may play a role in the genesis of some SCCHNs.     

Perivascular inflammatory reaction after percutaneous placement of covered stents

AIDS ocular complications have been researched in 70 hospitalised patients in the two main hospitals of Bamako (Mali) during one year (1992-1993). Men were predominant (sex ratio 1.6). HIV1 infections (67%) were most frequent than HIV1 + HIV2 (21.4%) or HIV2 infections (11.4%). Most of the patients were on the WHO's clinical stage III; 34% of them had ocular complications, quite often non infectious: cotonous nodules (10%), vascularitis (5.7%) and retineous haemorrhages (4.3%). Ocular opportunistic infections were rare: only one case of toxoplasmic chorio-retinitis was reported. Ocular complications were observed with all types of HIV. Vascular abnormalities were observed in the stage II or IV of AIDS and seemed, in Bamako, as a serious sign during the AIDS course.