Subperiosteal Implants Research Articles

A descriptive 18-year retrospective review of subperiosteal implants for patients with severely atrophied edentulous mandibles

Statement of problem Fabricating dentures for the patient with severe mandibular atrophy can be a challenge for both the dentist and patient. Subperiosteal implants with a mandibular overdenture may be a solution for the atrophic mandible. Purpose The purpose of this retrospective study was to review the survival of mandibular subperiosteal implants placed at the University of Missouri Kansas City (UMKC) School of Dentistry Graduate Prosthodontics program between 1982 and 2000. Material and methods Forty subperiosteal implants were placed in atrophic mandibles of 40 patients (33 women, 7 men) between 1982 and 2000. The age range of the patients was 47 to 80 years of age at time of placement (mean = 62 years). Each patient was reviewed clinically by an author (DJM). Manual depression and lifting of the framework were used to evaluate the stability of the implant. Additionally, the implants were observed for any movement. Each patient was questioned for pain or discomfort. Each patient was examined for observable inflammation and intraoral exposure of the framework and questioned as to whether the implant had satisfied the patient and met the patient's expectations. Results Thirty-nine of the 40 original patients were recalled in 2000. One patient had died. Fourteen patients had implants for over 10 years, 12 patients had implants between 5 and 10 years, and 12 patients had implants for less than 5 years (mean time of implant service = 8 years). Thirty-eight patients had the implant in place with no sign of inflammation or mobility, 1 patient with diabetes had inflammation around one of the struts. All patients were wearing their prostheses, and there was no sign of exposed implant framework for any patient. All patients reported a high level of satisfaction with the implant. Conclusions Within the limitations of this study, the mandibular implants placed at UMKC were still functioning, and all patients denied any discomfort or pain from the prostheses. Patients reported they were comfortable and able to function with the implant-supported prosthesis.

Analysis of HA-coated subperiosteal implants.

Bone atrophy is often encountered in the endentulous patient. With many clinicians performing bone grafting and augmentation techniques, there appears to be a decreased use of the subperiosteal implant modality for prosthetic stabilization. In recent years, there seems to be a decreasing number of literature reports and fewer academic presentations about the subperiosteal implant technique. Additionally, the American Academy of Implant Dentistry deleted this requirement for fellowship in its bylaws at its 1999 annual meeting. The purpose of this paper is to present the success and complication rates of 22 hydroxyapatite-coated subperiosteal implants placed over a 10-year period. Correlations between arch type and full vs unilateral subperiosteal implant cases are analyzed.

A clinical study on unfavorable cases of dental implant

The clinical analysis of 462 patients (154 men and 308 women) with problems of implant therapy done at other clinics is reported. They visited the clinic for oral implant of the Tokyo Medical and Dental University Hospital during the period from January 1996 to March 2002. The results were as follows: 1) The majority of the patients (76.6%) were 40 to 69 years of age. 2) Of the total patients, 26.8% had been referred from the other outpatient clinics in our hospital, 14.7% from private dental offices and 2.6% from attending doctors. 3) There were 361 patients with complications related to the implant therapy. Seventy-six patients asked for second opinions concerned about a diagnosis or treatment recommendation. Thirty patients required maintenance of the implants. 4) The most common complications observed were peri-implantitis (184 cases). Prosthodontic complications (72 cases) included framework/resin/veneering material fractures, screw loosening and fractures. There were implant fractures in 21 cases, sensory disturbance in 20 cases, problems related to sinus in 13 cases, problems of connected teeth in 30 cases and phonetic/esthetic complications in 10 cases. 5) The types of problem implants were osseointegrated implants (196 cases), alumina-ceramic implants (74 cases), metallic blade-type implants (35 cases), pin-type implants (10 cases), subperiosteal implants (6 cases) and other implants.

口腔インプラントによる上顎洞炎

Dental implants are widely used for partially or fully edentulous patients, however, cases of maxillary sinusitis caused by dental implants have been reported.We treated 26 such patients in Osaka Dental University hospital from 1973 to 2001. A clinical analysis was performed in 27 cases, and the results were as follows:1. Of the 26 cases, 10 patients were males and 16 patients were females; the mean age was 54.5 years old.2. Type of implants: 19 patients received endosteal implants, 7 were fitted with subperiosteal implants and 1 got endodontic and endosteal implants.3. The period from implant insertion to symptoms of maxillary sinusitis: 7 patients (25.9%) had onset within a month and 9 patients had onset within a year (33.3%).4. Period from symptoms to diagnosis: 12 cases (44.4%) were diagnosed within a month and 20 cases (74.1%) were diagnosed within 6 months.5. To prevent maxillary sinusitis, investigation of the volume of maxillary bone is required, followed by choosing the proper surgery method and type of implants.6. It is important to quickly decide whether sinus surgery is necessary or not and to remove implants causing maxillary sinusitis if they perforate the maxillary sinuses.

The effect of bone anchoring and micro-grooves on the soft tissue reaction to implants

Here we aimed to compare the tissue reaction to smooth and micro-grooved implants, at different implantation sites. We hypothesised that subperiosteally less mobility is to be expected between an implant and the surrounding tissue, which can lead to a more subdued tissue response. In addition, we hypothesised that a similar effect can be reached when substrata are equipped with micro-grooves. Poly- l-lactic acid smooth or micro-grooved surfaces (width 2 or 10 μm, depth 1 μm) were implanted subperiosteally on the frontal bone of the skull, or subcutaneously in the flanks of goats for 2, 4 and 12 weeks. After sacrifice, implants and surrounding tissue were histologically processed. Light microscopical and histomorphometrical evaluation of the histomorphometrical analyses, capsule thickness, capsule quality and implant–tissue interface was performed. In addition, we stained for α-smooth muscle actin, collagen and CD-68 expression. All implants were surrounded by a fibrous capsule. Capsules around subperiosteal implants were more matured than around subcutaneous implants. In time, capsule thickness significantly decreased around subperiosteal implants, but increased around subcutaneous implants. Also, nowhere differences were found in the presence of collagen or α-smooth muscle actin. The interfacial cells around all implants frequently showed staining for the monocyte–macrophage marker CD-68. We concluded that in this model, decreased mobility of an implant relative to the surrounding tissue did positively influence the peri-implant tissue response, but the applied surface topography did not.

Effect of aging on bone formation induced by recombinant human bone morphogenetic protein-2 combined with fibrous collagen membranes at subperiosteal sites.

This study was designed to examine the effect of aging on bone formation induced by recombinant human bone morphogenetic protein-2 (rhBMP-2) combined with a fibrous collagen membrane (FCM). Implantation was done subperiosteally in bilateral palatal grooves in 34 male Wistar rats divided into three age groups: a 10-week-old group (10w group), a 30-week-old group (30w group) and a 70-week-old group (70w group). RhBMP-2-combined FCMs were implanted on the left palatal grooves as BMP-implanted sites (BMP site), while rhBMP-2 was not implanted on the right palatal grooves as control sites. The rats were sacrificed 6 weeks after implantation, and histometric evaluations were performed. New bone formation was observed in every site of each age group and the new bone was almost completely continuous with the original bone. The new bone volume (NBV) of the BMP site was significantly higher than that of the control site in each age group. The NBV of both the control and BMP sites were highest in the 10w group and lowest in the 70w group. The disparity of NBV between the control and BMP sites, which indicated the response to implanted BMP excluding the effect of skeletal growth and surgical stimulation, did not significantly differ among the age groups. These results indicate that rhBMP-2-combined FCM has the ability to induce new bone formation continuous with original bone even in senescent rats. Furthermore, it appeared that, in the case of palatal subperiosteal implantation, the responsiveness to implanted BMP was independent of age, although the total volume of newly formed bone declined with aging.

Patient screening and medical evaluation for implant and preprosthetic surgery.

Implant and preprosthetic surgeries aim to restore normal anatomic contours, function, comfort, aesthetics, and oral health. As such, they are not life-saving procedures. The prime concern must therefore be to not undermine the patient's overall health and safety. It is then that every step must be taken to select the appropriate treatment plan and maximize the longevity of the implanted system, including the overlying prostheses. One important category into which a number of possible complications may fall is the inadequate systemic screening of patients prior to implant and biomaterial insertion. Without wishing to enter into the whole human pathology, it is no longer appropriate to limit the general contraindications of implantology to the traditionally considered malfunctions of the pancreas, liver or hematopoietic system and to ignore the devastating long-term effect of smoking or inadequate dietary habits. There are, in fact, a number of systemic problems that may create major risk factors. On the other hand, modern standards of care should not systematically exclude the use of implant surgery on patients with relative or marginal health conditions without exploring the possibilities of improving and stabilizing those conditions. As newer techniques of general anesthesia and intravenous sedation are more frequently used on an ambulatory basis, allowing implant surgeons to take their patients into various degrees of consciousness or deep sedation, the patient screening should also take into consideration factors related to this form of management. An arbitrary guideline for patient selection may be based on the classification of the American Society of Anesthesiology. This guideline restricts (with very few exceptions) intraosseous implants and implant-related graft surgeries on patients who fall into ASA1 or ASA2 categories of the classification. In the domain of subperiosteal implants for treatment of advanced atrophy of the mandible, the body response seems to be much less dramatic than to endosseous devices or to grafted sites. The cortical histoarchitecture and metabolism are, by far, less affected by organ disorders than are endosseous structures. This article presents a number of absolute contraindications and analyzes a series of relative contraindications for which the doctor's judgment remains the decisive factor. In this latter case, it proposes treatment patterns that could optimize certain marginal health conditions or stabilize unbalanced biological functions prior to or at the time of surgery. As life expectancy in the industrial countries is continuously increasing, a greater number of elderly patients are equipped with implant-supported prosthetics. The effort must therefore be focused on keeping a regular and watchful eye on their general health and screening for possible geriatric conditions responsible for long-term implant failure. Will a minimum knowledge of internal medicine be a prerequisite for future academic implant education?

Ridge-lapping Restorative Crowns Over Endosteal and Subperiosteal Implant Abutments

Crowns on countless dental implant abutments have been successfully ridge lapped for over 25 years. When properly fabricated, ease of cleansing and maintenance of health at the pergingival site is routine. The advantages of this technique are significant. It promotes pleasing aesthetic results almost regardless of the vestibulo-lingual and mesio-distal location of the abutment relative to the required position of the crown. The technique-sensitive procedures associated with the creation and maintenance of acceptable emergent profiles are rendered unnecessary. Ridge lapping is compatible with abutment heads of any diameter and configuration and with cementable or screw-retained fixed prostheses. This article discusses current opinion and controversy regarding ridge lapping of crowns over implant abutments and offers step-by-step procedures in the diagnosis, design, fabrication, and professional and home care maintenance of highly aesthetic ridge-lapped crowns over abutments of the common dental implant modalities.

Long-term Follow-up of Unilateral Partial Subperiosteal Implants Placed in the Maxilla and Mandible

Long-term Follow-up of Unilateral Partial Subperiosteal Implants Placed in the Maxilla and Mandible

A 41‐year history of a mandibular subperiosteal implant

The subperiosteal implant was originally described in the 1940s. The inadequate long-term results of subperiosteal implants are in contrast to the excellent results documented for endosseous osseointegrated oral implants. Consequently, subperiosteal implants and other soft-tissue-anchored implants should not be used presently. Furthermore, these implants are seldom seen today, because they generally were removed rather shortly after placement. The present report documents a full 41-year history of a mandibular subperiosteal implant inserted in 1957 by focusing upon the consequences of not removing an implant in spite of continuous periods of complications during 4 decades. Implant exposure, inflammation, infection, and fistula formation occurred persistently. Total implant removal was refused by the patient in 1973. After 25 years without control, tremendous resorption of the mandible was observed in 1998. Consequently, the entire implant was then removed. Placement of osseointegrated oral implants was impossible without extensive autogenous bone grafting. The present report has demonstrated that regular control of patients with subperiosteal implants is mandatory. Furthermore, subperiosteal implants should definitely be removed, if continuous periods of complications occur.

A 41-year history of a mandibular subperiosteal implant

The subperiosteal implant was originally described in the 1940s. The inadequate long-term results of subperiosteal implants are in contrast to the excellent results documented for endosseous osseointegrated oral implants. Consequently, subperiosteal implants and other soft-tissue-anchored implants should not be used presently. Furthermore, these implants are seldom seen today, because they generally were removed rather shortly after placement. The present report documents a full 41-year history of a mandibular subperiosteal implant inserted in 1957 by focusing upon the consequences of not removing an implant in spite of continuous periods of complications during 4 decades. Implant exposure, inflammation, infection, and fistula formation occurred persistently. Total implant removal was refused by the patient in 1973. After 25 years without control, tremendous resorption of the mandible was observed in 1998. Consequently, the entire implant was then removed. Placement of osseointegrated oral implants was impossible without extensive autogenous bone grafting. The present report has demonstrated that regular control of patients with subperiosteal implants is mandatory. Furthermore, subperiosteal implants should definitely be removed, if continuous periods of complications occur.

Ceramic-coated implant systems.

Practitioners have used hydroxyapatite-coated (HA-coated) endosseous and subperiosteal implants in various forms for many years. These have included root forms in both screw and cylindrical shapes, blades, and subperiosteals. The clinical predictability remains controversial and subject to claims and counterclaims. The early days of dental implantology involving root-form implants recommended their placement in fully edentulous cases only, and anterior to the maxillary sinus and mental foramen. Today's philosophy and rationale of dental implantology include the placement of a single implant replacing a missing natural tooth (especially where the teeth adjacent to the edentulous site have no caries or restorative experience). Implants are used to replace the natural dentition in one quadrant/segment, often preceded or accompanied by ridge augmentation and/or sinus grafting if sufficient bone is not present. So we have to address the clinical predictability of survival in terms of indications, quantity, and quality of bone. Clinical data and experience suggest that hydroxyapatite-coated (HA) dental implants may (and possibly should) be used in (1) Type IV bone, (2) fresh extraction sites, (3) grafted maxillary and/or nasal sinuses, or (4) with short implants (< or = 10 mm in length).

Effect of hydroxyapatite content on physical properties and connective tissue reactions to a chitosan-hydroxyapatite composite membrane.

The present study investigated the effect on certain physical properties of adding various amounts of hydroxyapatite (HAP) to chitosan sol. Also investigated were connective tissue reactions to a composite membrane that is being developed for possible use in guided tissue regeneration and for the limitation of HA particle migration at sites of implantation. The physical properties evaluated were shrinkage, tensile strength, hardness, calcium ion release, and morphology. Assessment of physical properties indicated that a ratio of HA to chitosan sol of 4/11 by weight is optimal in the preparation of the composite membrane. Subperiosteal implantation of the membranes over rat calvaria revealed that the membranes were well tolerated, with fibrous encapsulation and occasional areas of osteogenesis. Increasing the hydroxyapatite content seems to enhance membrane degradation.

Ramus hinges for excessive movements of the condyles: a new dimension in mandibular tripodal subperiosteal implants.

Some subperiosteal mandibular implants of the earlier designs failed because of bone resorption beneath the posterior portions of the implant. Conversely, bone loss was observed rarely in the anterior region. The resorption was more profound posteriorly because there can be as much as 250 lb. of biting force per square inch and the bone is more porous than in the symphyseal region, which receives about 25 lb. per square inch. The independent movements of the condyles and the inferior border of the mandible at the gonial angles have dictated the success or failure of conventional mandibular subperiosteal implants in many of the earlier designs. Often, the rigidity of the implant framework prevents its posterior portion from moving in unison with the flexion and flexibility of the condyles upon the opening and closing of the mouth. Flexure usually is 2-4 mm in range and varies according to the quality of bone, age, sex, and musculature of the patient. Approximately 2% of these patients demonstrate movements of up to 4 mm. This has influenced an altered approach to posterior design-especially with tripodal mandibular subperiosteal implants. A brief history of the contributions of the earlier pioneers and their important contributions to the subperiosteal implant follows: G. Dahl inserted the first mandibular subperiosteal implant and was awarded his patent in 1941. Gershkoff and Goldberg, were the first to report clinical cases with mandibular subperiosteal implants in the United States. N. Berman reported on a direct bone impression of the mandible and transosseous wiring of the implant to the bone for stabilization. I. Lew introduced his own surgical bone impression technique for the mandibular subperiosteal implant and had published case histories on maxillary and mandibular implants. B. D. Weinberg reported an early unilateral subperiosteal implant consisting of a latticework portion that seated over the bone connected to the protruding post by four uprights. Leonard I. Linkow reported on the posterior unilateral mandibular subperiosteal implant. He followed up with a 5-year report, an 8-year follow-up report, and a 12-year report. R. L. Bodine reported his experiences with mandibular subperiosteal implants. A. N. Cranin and P. Schnitman introduced the Brookdale bar for an improved support of an overdenture for the mandibular subperiosteal implants. L. I. Linkow made some significant changes in the mandibular subperiosteal implant. D. D'Alise reported on the O-ring design for retention of implant dentures. R. A. James reported on the support system and perigingival mechanism surrounding oral implants and changed the subperiosteal based on peri-implant tissue behavior. L. I. Linkow reported on an entirely new mandibular tripodal design concept as well as a distinct change in the surgical protocol for obtaining the bone impressions without exposing those parts of the body of the mandible from the mental nerves to the ascending rami.

Stable Fixation of Subperiosteal Implant by Penetrating Screw Fixation with Metal Framework into Jaw Bone

Stable Fixation of Subperiosteal Implant by Penetrating Screw Fixation with Metal Framework into Jaw Bone

Patient screening and medical evaluation for implant and preprosthetic surgery.

Implant and preprosthetic surgeries aim to restore normal anatomic contours, function, comfort, aesthetics, and oral health. As such, they are not life-saving procedures. The prime concern must therefore be to not undermine the patient's overall health and safety. It is then that every step must be taken to select the appropriate treatment plan and maximize the longevity of the implanted system, including the overlying prostheses. One important category into which a number of possible complications may fall is the inadequate systemic screening of patients prior to implant and biomaterial insertion. Without wishing to enter into the whole human pathology, it is no longer appropriate to limit the general contraindications of implantology to the traditionally considered malfunctions of the pancreas, liver or hematopoietic system and to ignore the devastating long-term effect of smoking or inadequate dietary habits. There are, in fact, a number of systemic problems that may create major risk factors. On the other hand, modern standards of care should not systematically exclude the use of implant surgery on patients with relative or marginal health conditions without exploring the possibilities of improving and stabilizing those conditions. As newer techniques of general anesthesia and intravenous sedation are more frequently used on an ambulatory basis, allowing implant surgeons to take their patients into various degrees of consciousness or deep sedation, the patient screening should also take into consideration factors related to this form of management. An arbitrary guideline for patient selection may be based on the classification of the American Society of Anesthesiology. This guideline restricts (with very few exceptions) intraosseous implants and implant-related graft surgeries on patients who fall into ASA1 or ASA2 categories of the classification. In the domain of subperiosteal implants for treatment of advanced atrophy of the mandible, the body response seems to be much less dramatic than to endosseous devices or to grafted sites. The cortical histoarchitecture and metabolism are, by far, less affected by organ disorders than are endosseous structures. This article presents a number of absolute contraindications and analyzes a series of relative contraindications for which the doctor's judgment remains the decisive factor. In this latter case, it proposes treatment patterns that could optimize certain marginal health conditions or stabilize unbalanced biological functions prior to or at the time of surgery. As life expectancy in the industrial countries is continuously increasing, a greater number of elderly patients are equipped with implant-supported prosthetics. The effort must therefore be focused on keeping a regular and watchful eye on their general health and screening for possible geriatric conditions responsible for long-term implant failure. Will a minimum knowledge of internal medicine be a prerequisite for future academic implant education?

The complete maxillary subperiosteal implant: an overview of its evolution.

The complete maxillary subperiosteal implant: an overview of its evolution.

Application of stereolithography to subperiosteal implant manufacture.

Subperiosteal implants are an accepted and proven technique with a good long-term outcome. Although a technique of computed tomography to computer-assisted machining became available to drop the number of surgeries to one for ascertainment of bone topography, the problem of accurate bone modeling remains an issue. The advent of stereolithography as a new tool for modeling anatomy for subperiosteal implants and the advances in computed tomography offer a higher degree of build accuracy and repeatability than available before.

Subperiosteal implantation of various RF magnetron sputtered Ca-P coatings in goats.

The aim of this study was to obtain more information about the initial biological events around RF magnetron sputtered calcium phosphate (Ca-P) coatings. Therefore, uncoated and coated disks were inserted subperiosteal into the tibia of a goat. The coatings were deposited on commercially pure titanium. The thickness of the coating was 0.1 or 2.0 microm. All the as-sputtered coatings were subjected to an additional heat treatment for 2 h at 500 degrees C. After 1 and 3 weeks of implantation the experimental disks were retrieved and prepared for histological and physicochemical analysis. The histological results demonstrated that the periosteum covered the specimens after both implantation periods. In between the periosteum and implant an acellular layer and a collagen matrix was observed. Energy dispersive spectrometry revealed that the acellular layer consisted of C, Ca, and P ions for the 0.1 microm thick Ca-P coatings. The 2 microm thick Ca-P coatings also showed the presence of sulfate ions in this layer. Only organic material was found on the titanium disks. Further, SEM showed that even after 3-week implantation, a substantial thickness of both coatings was still maintained. Thin film X-ray diffraction demonstrated that after both implantation periods, the CaP-0.1 coating was still present. FTIR of the retrieved specimens demonstrated on the coated disks the formation of additional carbonate apatite (CO3-AP) associated with an organic phase (NH2 groups). On basis of these findings we conclude that our experimental approach is very suitable for the investigation of the healing process around Ca-P coatings. Further, we again demonstrated that the initial interfacial response to Ca-P materials differs from titanium.

Initiation of alveolar ridge augmentation in the rat mandible by subperiosteal implantation of octacalcium phosphate

The study was designed to investigate the process of bone formation caused by implantation of octacalcium phosphate as well as stability of the bone formed at the alveolar ridge. Synthetic octacalcium phosphate was implanted into a subperiosteal pocket in the rat mandible. Bone formation at the alveolar ridge was examined radiographically and histologically between 1 and 48 week(s) after implantation. Radiopacity of the octacalcium phosphate implant became obvious in week 2. Osteogenesis was initiated from the bone surface near the implantation site and multinucleated giant cells appeared on the implanted octacalcium phosphate in week 1. More apposition of new bone was observed on the implanted octacalcium phosphate in week 2 or later. Some implants were directly enclosed by newly formed bone and no cellular component was seen between the implant and the bone matrix. Many octacalcium phosphate implants were enclosed by bone, whereas the augmented ridge was not seen radiographically in week 24 or later. If its persistence can be improved, octacalcium phosphate could be used to augment atrophic alveolar ridges.