Dentoalveolar morphology: evaluation of natural root form versus cylindrical implant fixtures

The function of implant-supported restorations is now routinely achieved. As a result, the emphasis in restorative implant dentistry has shifted from function to aesthetics and the biocompatibility of the materials utilized. The learning objective of this article is to review the three major components essential to achieving natural aesthetics in implant-supported restorations--hard tissue dynamics, soft tissue dynamics, and dental aesthetics. Particular emphasis is directed to the dentoalveolar anatomy and morphology. Analysis of the tooth root morphology and dimensions has resulted in the design and fabrication of restorative components with dimensions that closely resemble the natural tooth anatomy and aesthetics. A system of transmucosal abutments has been designed, and its utilization is presented in this review.     

Use of provisional restorations to enhance soft-tissue contours for implant restorations

The objective of restoring missing teeth with implant-supported restorations should not merely be achieving osseointegration with an implant and a biomechanically sound restoration. The objective must be the esthetic and functional restoration of the missing teeth. To achieve this, proper treatment planning is critical. Precise implant placement and delicate soft-tissue manipulation during surgery will allow the restorative dentist to enhance the peri-implant soft-tissue contours with the use of provisional restorations. Empirically, it seems that the earlier the provisional restoration is delivered in the treatment process the more ideal the esthetics. Several methods of using provisional restorations to enhance soft-tissue contours are presented. The concept of immediately delivering provisional restorations on placement of an implant is discussed.     

Problems associated with the atrophic mandible

A range of treatment options has been presented regarding the use of dental implants to rehabilitate patients who otherwise have compromised function using conventional tissue-borne prostheses. This patient population offers significant challenges to both the surgeon and the prosthodontist. Generally speaking, IODs retained on two or more endosteal osseointegrated implants; transosteal, subperiosteal, ramus frame implant-supported and implant-retained prostheses, and a totally implant-supported design offer options to treat the severely atrophic mandible. When bone support or volume is so lacking that augmentation procedures are required, bone grafting can be considered as a treatment option. The state-of-the-art of implant treatment for the atrophic mandible offers to the dental professional and patient a variety of options. Thus far, it is too early to make specific recommendations as to which treatment offers the best option for each patient. It is fair to say that the ISP remains the gold standard against which other treatments can be compared.     

Epinephrine in digital blocks: revisited

STATEMENT OF PROBLEM: Implant treatment in the United Kingdom has been provided mainly in specialist, regional dental hospitals. However, increasingly, general dentists are providing implant-supported prostheses in a private office setting. PURPOSE: This study investigated the nature, timing, and frequency of complications associated with single tooth implant therapy in a dental hospital and two dental offices. METHODS: The dental records of 58 patients provided with 76 implants during the period of 1989-95 were reviewed retrospectively. Fifty-three single tooth crowns on implants were placed by general dentists and 23 by specialists in the dental hospital. RESULTS: Implant survival rate was 96%. Twenty-eight guided bone regeneration procedures were required, including 13 unplanned ones. Prosthodontic complications included the need for recontouring of three crowns and the recementation of three crowns. Only two abutment screws required retightening. Peri-implant soft tissue inflammation occurred around six crowns and recession around two. CONCLUSION: The single tooth implant-supported crown appears to be an effective and durable restorative treatment with a relatively low prevalence of postoperative complications.     

Implants in the partially edentulous patient: restorative considerations

Restorative considerations are critical to the long-term success of fixed implant-supported prostheses, especially in the posterior quadrants of the partially edentulous patient. The parafunctional habit of bruxism must be identified and addressed. The restoration should dictate implant placement. Control of forces directed upon the prosthesis and implants is critical to long-term success. Anatomic limitations to implant placement and surgical procedures to correct these deficiencies must be considered for their impact on the prosthetic restoration. Nonaxial forces or bending moments should be minimized by the use of an adequate number, position and alignment of implants; by control of the occlusion; and by design of the prosthesis. The patient must understand the risks, limitations, costs and time commitments of implant restorations prior to treatment.     

Load factor control for implants in the posterior partially edentulous segment

There are inherent biomechanical differences in the implant treatment of completely edentulous arches and posterior partially edentulous segments. The partial prosthesis does not benefit from cross-arch stabilization and is, therefore, more susceptible to bending loads. Because of the difference in mobility between teeth and implants, implants may carry a major share of load when mixed with teeth in the same quadrant. However, the frequency of implant overload in posterior partial restorations is low, and, with appropriate treatment planning, overload in these situations is almost always preventable. A checklist procedure is proposed to help the clinician enumerate and evaluate deleterious load factors. By screening patients for such factors in advance, the clinician may identify and avoid potential overload situations when conceiving and fabricating implant-supported posterior partial prostheses. A second checklist, for use at follow-up appointments, lists alarm factors that serve as an early warning of overload once the prosthesis is in place.     

Altered patterns of DNA methylation on chromosomes from leukemia cell lines: identification of 5-methylcytosines by indirect immunodetection

The feasibility of implant treatment in patients after oral ablative tumor surgery has not yet been investigated with consideration of the requisite high periodontal standards. A report on this topic has to deal not only with implant survival but also with implant health, bone response, soft tissue health, failure pattern, time of failure, and ease of restoration. For the assessment of an implant system, an overview must be accomplished that takes into account the different restorations used and their interaction with the implant system that was used. This study presents the Bone-Lock implant system (Howmedica Leibinger GmbH, Freiburg, Germany) in a retrospective investigation after 5 years of follow-up with special emphasis on the prosthetic restorations used following resection of oral malignancies. From early in 1990 through June 1996, we inserted 210 dental endosteal Bone-Lock implants (58 patients) after oral tumor resectioning. Included in the study were 45 patients with 162 implants and prosthetic restorations that had been loaded for 1 year (dentures retained by telescopic or bar-clip or ball attachments, implant-supported prostheses, tooth-to-implant connected bridges). Regular follow-up consisted of evaluation of the Plaque Index (Silness and L?e) and of the Sulcus Bleeding Index (L?e), measurements of pocket probing depth, implant mobility (by means of the Periotest method), bone resorption (according to X-ray findings), and a questionnaire that registered patient satisfaction. The results were evaluated for each restoration and were compared with baseline standards. The overall 5-year survival rate was 83.2%. For implants that had been in place for over 365 days, the survival rate was 93%. The investigation showed that after resection of oral malignancies, patients could be treated with dental implants and superstructures with long-term efficacy similar to that found in healthy subjects considering internationally accepted standards. Implant treatment in tumor patients appeared to offer the most positive periodontic results when use of bar-clip or telescope-retained overdentures was involved. The patient satisfaction level with the described prosthodontic treatment was satisfactory.     

Comparison of position repeatability of a human operator and an industrial manipulating robot

STATEMENT OF PROBLEM: Implant-supported restorations in the partially edentulous jaw have been performed at the Mayo Clinic for more than 10 years. Clinical performance of the implants and the prostheses should be reported to ensure effectiveness of this procedure. PURPOSE: This retrospective study described results for implant survival, implant fracture rate, prosthetic complications, and design changes that may impact these results. MATERIAL AND METHODS: A retrospective chart review was conducted of all registered implant patients in a large multispecialty medical center. Patients with a partially edentulous jaw who had received endosseous implants to support and retain dental prostheses were included in this review. Implant survival and fracture, prosthetic complications, and demographic data were recorded and analyzed through Kaplan-Meier methods. RESULTS: A total of 1170 implants were placed in four anatomic locations: anterior maxilla, posterior maxilla, anterior mandible, or posterior mandible. Location of implants was shown to have no effect on implant survival (p = 0.7398), implant fracture rates (p = 0.2385), screw loosening (p = 0.8253), or screw fracture (p = 0.2737). Development of new restorative components has resulted in significantly better rates of implant survival without fracture (p = 0.0054), screw function without loosening (p < 0.0001) and screw function without fracture (p = 0.0013). Implant survival seems to have been improved with the new components (p = 0.0513). CONCLUSIONS: Implant survival in this study was independent of anatomic location of implants. Virtually all clinical performance factors were improved by design changes in implant restorative components that were brought to market in early 1991.     

Lipid peroxidation in patients with ischemic heart disease, hyperlipidemia and/or hypertension while polyunsaturated omega-3 fatty acids of plant and animal origin were in their diet

Missing anterior teeth are being replaced by implant-supported restorations quite frequently in modern dentistry. Providing the patient with a temporary prosthesis prior to or following implant fixture placement must satisfy established esthetic and functional criteria. When orthodontic treatment is included as part of the overall treatment effort, additional considerations include the retention and stabilization of newly established tooth positions. This article describes the fabrication, use and advantages of a provisional anterior prosthesis that replaces missing teeth prior to or following implant placement.     

Reconstruction of an atrophic edentulous maxilla with unilateral cleft lip and palate (UCLP) using sub-antral augmentation and osseointegrated implants: case report and 3-year follow-up

With the current sophisticated, multidisciplinary approach to the treatment of cleft palate, it is anticipated that most patients with this deformity will enjoy good dental health and function. However, due to the number of older adults who were not treated with primary bone grafting and orthodontic therapy, there remains a significant number of potential candidates who may benefit from dental implants and implant-supported prostheses. Although it was not necessary in this case, a pharyngeal extension may be added to the maxillary denture to further improve speech and deglutition. This case report presents a three-year follow-up of a complex reconstruction of a highly compromised, edentulous patient. Stable fixation of the maxillary prosthesis results in a complete return to function in an individual for whom traditional dental prosthetics had resulted in ten years of failure and frustration. Combining the disciplines of reconstructive surgery and implant prosthetics enables the clinician to achieve a predictable result (Figures 12 and 13). While this case represents an extreme example, there are millions of patients for whom implant dentistry can provide life-changing benefits.     

Managing malrelated arches and limited vertical space for implant-supported overdentures: a case report

Advancements in implant therapy have expanded the prosthetic options available to treat edentulous patients. The dental professional must be able to accurately diagnose the status of the intraoral environmental in order to provide the patient with appropriate treatment and a suitable restorative result. Skeletal relationships, arch malalignment, implant angulation, and ridge morphology must be evaluated during initial treatment planning and incorporated into the definitive prosthetic result. This case report demonstrates the application of an implant-supported prosthesis to address the various complications presented in the treatment of edentulous patients.     

"The view" and the canine connection: an atlas of mandibular anterior tooth esthetics

Restoring splinted mandibular incisors and canines with full crown restorations has always presented a challenge in creating an esthetic illusion of reality of normal individual teeth. This treatise is designed to present the rules for mandibular anterior esthetics that have been distilled from almost 4 decades of clinical practice of restoring dentitions that have been severely compromised by the deformities of disease or accident. The resultant formula systematically creates the desired results with a high degree of predictability.     

Cervical contouring concepts: enhancing the dentogingival complex

The importance of the mucogingival complex in any restorative procedure has long been recognized, and various surgical and nonsurgical procedures have been developed to restore the compromised gingiva to its original health. The learning objective of this article is to review nonsurgical restorative techniques to manipulate the soft tissue surrounding the cervical aspect of the restored tooth into a more favorable contour. The techniques presented are applicable to direct and indirect restorations. Six case reports are used to illustrate the various clinical procedures. The techniques include: Supragingival direct restorative techniques, such as recontouring intact dentition; and intracrevicular indirect techniques, such as recapturing the soft tissue of deficient crown restorations, re-engineering recessed injured tissue, re-creation of hyperplastic injured tissue, re-engineering hyperplastic recessed posttrauma tissue, and re-engineering the periprosthetic envelope.     

Implant-supported overdenture therapy: a retrospective study

All patients (n = 46) treated with implant-supported overdentures at the Department of Prosthetic Dentistry, Dental and Medical Health Centre, Halmstad, Sweden, from 1986 to 1993 were studied. The clinical examination was completed in 1994. The material was divided into two subgroups: Group A had been initially treatment planned for an implant-supported overdenture, and Group B had been planned for fixed prostheses but because of loss of implants before loading, treatment with a fixed prosthesis was not possible. The authors present their experience and patient reactions to overdenture therapy in two defined groups of patients. The implant failure rate before loading for Group A (n = 12) was 15% (six implants out of 39), and the rate before loading for Group B (n = 29) was 43.6% (68 implants out of 156). After prosthodontic treatment in Group A, the implant success rate after loading was 87.9%, and the overdenture stability was 84.6%. In group B, 17 implants placed in the maxillae were lost after overdenture therapy, which resulted in an implant success rate of 79.3%. A total of eight overdentures, all of which had been placed in the maxillae, were lost, resulting in an overdenture stability of 73.3%. In this study "change of retentive clips" was the predominant prosthodontic complication related to the overdentures, especially in Group B. Most of these complications (62%) occurred in patients with clinical signs of bruxism. Patient reactions to treatment with an overdenture were positive regarding esthetics for both groups. More negative views were recorded in Group B than in Group A in response to function and retention of the overdenture.     

Neurotensin is metabolized by endogenous proteases in prostate cancer cell lines

The predictability of implant-supported prostheses has been established. Although the original Br?nemark design has been successfully used in the mandible, esthetic, speech, and hygiene-related problems have been reported in maxillary fixed prostheses. Implant-overdentures can overcome some of the problems encountered in maxillary fixed prostheses. Milled-bar implant-supported overdentures fabricated by electric discharge machining are characterized by stability similar to a fixed prostheses and are removable for hygiene procedures. However, the procedure is costly and requires highly trained technicians. An alternative procedure to produce an accurately fitting metal suprastructure is presented. This procedure does not require additional technical skills and uses instruments and materials that are readily available and relatively inexpensive. The use of simple and easy to replace attachments allows repairs to be performed in the dental office, thus reducing maintenance cost. The overall result is a prosthesis that incorporates the features of a spark erosion overdenture at a fraction of the cost and that is available to a broader patient population.     

Establishing soft tissue integration with natural tooth-shaped abutments

The disparity in dimensions between implant fixtures and the exposed extraction sockets has resulted in the development of anatomically shaped abutments. Systems have been recently introduced that facilitate the fabrication of abutments to the configuration of natural teeth in the anterior maxilla. These systems permit development of an aesthetic emergence profile and contours for easy access in maintenance of oral hygiene of maxillary anterior single-tooth implant-supported restorations. The rationale for the development, indications, advantages, and clinical utilization of a recently introduced abutment system is discussed.     

Post and core reconstruction for fixed prosthodontic restoration

If the previous restorative therapy or dental caries has resulted in substantial loss of tooth structure, the abutment teeth for fixed prosthodontic restorations require a core reconstruction or a post and core. Small dentin defects can be restored with bonded cores; more extensive dentin defects that are often accompanied by previous endodontic treatment generally require additional support for the core material. A direct procedure with a bonded post is a viable treatment method. The decision to use either light-conducting all-ceramic zirconium or titanium as a post material depends on the aesthetic requirements present. The indications for a cast post and core as an indirect procedure for prosthodontic reconstructions appear to be decreasing. The learning objective of this article is to review the past and current post and core materials and techniques. Indications for core reconstruction with vital teeth and posts and cores for pulpless teeth are discussed.     

Successful chemotherapy in a patient with recurrent carcinoma of the urachus

OBJECTIVE: Titanium in other parts of the body, well known for its biocompatibility, was examined in an animal model for its use as an ossicular replacement material. STUDY DESIGN: The biocompatibility of titanium was studied in the middle ear of rabbits using light and scanning electron microscopy. Titanium pins were placed as middle ear prostheses or as free implants and were examined after 28, 84, 168, and 336 days. RESULTS: After 28 days, the prostheses were covered by regular mucosa. The free implants took up to 336 days to be totally epithelialized. There were no inflammatory cells observed on the surface of the material nor were unusual amounts of fibrous tissue seen. In addition, the titanium material exhibited an affinity toward bone. CONCLUSIONS: The results of this animal experiment indicate that titanium is a useful material for ossicular replacement prostheses.     

Two-implant-supported single molar replacement: interdental space requirements and comparison to alternative options

Posterior single-tooth implant restorations are subjected to an increased risk of bending overload. A high incidence of implant fracture has been reported when using a single standard 3.75-mm-diameter implant to support a molar restoration. The purpose of this article is to demonstrate the clinical feasibility of placing two implants to support a molar restoration and to compare this treatment option to the use of a single standard implant or a wide-diameter implant. Two osseointegrated dental implants used to support a molar restoration in interdental spaces as small as 10 mm is shown to be effective and predictable in 60 restorations over the past 7 years. The use of two implants provides more surface area for osseointegration and spreads the occlusal loading forces out over a wider area, reducing the potential bending forces that would otherwise exist in a single-implant molar restoration.     

PST, the essential surgical template

The anticipated prosthesis now dictates the placement and angulation of the implant, thereby improving the function and the aesthetics of the final result. To establish a logical continuity between the surgical phases and the planned prosthesis, it is essential to use a transfer device. The restorative clinician can request a precise position and orientation of each implant with this communication tool. However, it is difficult to use a conventional surgical template following the soft tissue reflection and during preparation of implant osteotomy. The proper positioning of each implant is difficult to achieve, especially on a completely edentulous maxilla where restorations require even more ideal implant placement.