PubMed Health⌕ Search

Biomedical subjects

J N Kent

Publications and source records attributed to J N Kent.

At least 19 recordsLinked to original sources
PubMed2003

A retrospective study of the costochondral graft in TMJ reconstruction.

A retrospective review of 76 costochondral grafts (57 patients) was undertaken to determine outcome with respect to the extent of previous surgery (none, disc surgery or soft tissue graft, alloplastic disc, alloplastic joint, previous graft) and to initial and preoperative diagnosis. The minimum follow up period was 2 years and for each patient both subjective (pain and dietary interference scores) and objective (interincisal distance) data was recorded. Collectively there was improvement in pain (mean 6.7 to 3.5) and diet (mean 2.2 to 3.0) scores with a moderate increase in interincisal distance (mean 21 to 24mm). In patients with no previous surgery, arthritic disease or congenital deformity the costochondral graft performed well but in patients with previous alloplastic discs and/or total joints the results were less predictable. A preoperative diagnosis of ankylosis was associated with a high complication and further surgery rate suggesting caution in this group of patients.

Adolescent↗
PubMed1998

Bone maintenance 5 to 10 years after sinus grafting.

PURPOSE: This radiographic study determined the amount of bone around hydroxyapatite (HA)-coated dental implants that were placed into bone-grafted maxillary sinuses. PATIENTS AND METHODS: Postoperative complex motion tomograms using the Grossman technique were taken on 16 patients who had 27 maxillary sinus grafts performed using particulate autogenous iliac bone with and without demineralized bone, autogenous iliac corticocancellous block with and without demineralized bone, and autogenous jaw bone with demineralized bone. Bone levels were measured from the new floor of the grafted sinus to the apex of the implant and to the alveolar crest. The resulting bone level measures were compared with the type of graft used. All patients had been restored for 5 to 10 years after simultaneous graft and implant placement. RESULTS: For all patients summed together, the average amount of bone from the top of the graft to the apex of the implant was 3.3 +/- 3.1 mm, and the average amount of bone from the top of the graft to the alveolar crest was 17.6 +/- 3.1 mm. The average level of bone in the sinuses of patients grafted with autogenous iliac bone was greater than the average level of bone in those grafted with autogenous bone combined with demineralized bone. CONCLUSION: The results of this study indicate that autogenous bone grafts are maintained in the maxillary sinus, but the results with autogenous bone alone are better than when demineralized bone is added. However, this difference may not be clinically significant.

Adolescent↗
PubMed1997

Sinus augmentation for dental implants: the use of autogenous bone.

Autogenous bone has been the material of choice at our institution since 1983. The criteria for a successful graft in the sinus have been fulfilled based on functional stability in patients followed-up over 10 years in selected cases. Of 173 implants placed into autogenous bone grafted sinuses, 20 have been lost in four patients. Long-term follow-up is recommended for all graft materials used to support posterior maxillary restorations.

Alveolar Ridge Augmentation↗
PubMed1994

Long-term follow-up on hydroxylapatite-coated cylindrical dental implants: a comparison between developmental and recent periods.

PURPOSE: To compare success rates for dental implants placed from 1985 through 1988 and from 1989 through 1991, and to investigate the factors associated with success or failure. PATIENTS AND METHODS: All hydroxylapatite-coated cylindrical implants placed from 1985 through 1991 were followed yearly. Lifetable survival analyses compared implant success for a "developmental period" from 1985 through 1988 (4 to 8 years follow-up) and a "recent period" from 1989 through 1991 (1 to 4 years follow-up). Reasons for success or failure, time from implant placement to removal related to failure reason, outcome after implant removal, and a morbidity analysis are included. RESULTS: The 7 to 8-year cumulative success rate for all implants placed in the developmental period (maxilla and mandible combined) was 86.5%; it was 84.2% for all maxillary implants and 87.5% for all mandibular implants. The cumulative success rate for all implants placed in the recent period was 97.5%; it was 97.5% for all maxillary implants and 97.6% for all mandibular implants. The difference between the two periods was statistically significant only for the anterior maxilla. Regression analysis on the interval success rates indicates that interval failure did not follow a linear relationship with time. The most common reasons associated with failure were lack of keratinized gingiva, poor oral hygiene, mechanical overload, and malposition. CONCLUSION: Comparison with previously reported cumulative success rates indicated learning curve experiences comparable with other implant systems. Improvements in hardware, surgical and prosthetic techniques, and patient selection have led to an improvement in success rates with the recent period implants.

Bone Resorption↗
PubMed1994

Maxillary sinus bone grafting.

When a patient is missing posterior teeth and desires a fixed prosthesis, bone grafting is often needed. Since 1983, our clinical experience indicates that sinus grafting can provide very good restoration of the posterior quadrants. If the implants are loaded in a physiologically stable manner, one may expect maintenance of bone levels.

Alveolar Bone Loss↗
PubMed1993

Update on the vitek partial and total temporomandibular joint systems.

A retrospective recall study was done on 262 VK I (N = 138) and VK II (N = 124) (Vitek, Inc, Houston, TX) partial and total temporomandibular joints placed between 1982 and 1990. The cumulative success rate of VK I total joints observed for up to 10 years was approximately 20%, whereas the success rate of VK II total joints observed up to 6 years was approximately 80%. At the 5- to 6-year interval for each, these rates were 44% and 79%, respectively. Wear of the Teflon fluorinated ethylene propylene polymer surface was the primary reason for VK I failure; there was no material failure of the VK II prostheses. Slightly better pain relief, increase in interincisal opening, improvement in diet, and greater overall satisfaction were noted with the use of VK II. A highly significant improvement in success data was found if no surgery had been performed before either VK I or VK II total joint placement. Rib grafts were not particularly helpful after removal of total joint prostheses, particularly if the patient had a history of multiple surgeries. Total temporomandibular joint surgery must be reserved for patients in whom alternative surgical methods have failed or are no longer indicated. All total joint implants, particularly the VK I, must be observed closely with clinical examination and imaging and removed at the earliest sign of material failure.

Adult↗
PubMed1993

Maxillary sinus grafting for totally and partially edentulous patients.

The presence of the maxillary sinus and lack of adequate bone to stabilize the implants could make traditional implant placement impossible. The solution includes grafting bone to the posterior maxilla to provide adequate bone support for implant integration and long-term survival.

Bone Transplantation↗
PubMed1993

Long-term results on VK partial and total temporomandibular joint systems.

This article reviews the results obtained on 262 VK partial and total temporomandibular joint (TMJ) procedures followed up to 10 years. VK I total joint (placed 1982 to 1986) cumulative success rate was 44% at 6 years and 20% at 10 years, while VK II (placed 1986 to 1990) cumulative success rate was 80% at 6 years. Material wear of the Teflon FEP surface of the VK I fossa was the most common reason for failure. There were no VK II material failures. A significant improvement in clinical success parameters for both prostheses was found if no previous surgeries were done before VK I or VK II total joint placement. Rib grafts were not helpful after removal of total joint prostheses if patients had a history of multiple procedures. Total TMJ prostheses must be reserved for patients with alternative surgical failures or when these procedures are no longer indicated. Close monitoring by clinical examination and imaging is necessary.

Adolescent↗
PubMed1993

Cylindrical HA-coated implants--8-year observations.

Controversy exists concerning the integrity of hydroxyapatite-coated implants over time. The Louisiana State University Oral and Maxillofacial Surgery Department studied data of 1,374 HA-coated implants that were placed from 1985 to 1991. Data were examined according to life-table survival, interval success rate, reasons for failure, and long-term effects. The rate of integration for HA-coated implants was found to be superior to that of noncoated, titanium implants. The HA-coated implants also showed excellent survival and function rates.

Dental Implants↗
PubMed1992

Multicenter evaluation of temporomandibular joint Proplast-Teflon disk implant.

Seven oral and maxillofacial surgeons from all U.S. American Association of Oral and Maxillofacial Surgeons districts participated in a retrospective study of Proplast II Teflon interpositional implants that were placed after meniscectomy in 680 TMJs (465 patients) and followed from 6 to 76 months. At longest follow-up a relatively high number (85.9%) 584 of 680 implants were in place with an average weighted follow-up of nearly 32 months. Of these 584 joints, a very high number, 540, (92.4%) were asymptomatic, however, 224 asymptomatic and 25 symptomatic joints with the implants in place exhibited some degree of condyle resorption that included 45 with malocclusion. In the worst case scenario, if condylar resorption is indicative of a worn Proplast II Teflon interpositional implant, then 364 (54%) of the 680 implants may fail. Failure rates per year range from Vitek's reported 3% to an average 18% clinician report in the literature. Higher rates are reported by individual clinicians, and our recent in vitro wear tests of Proplast II Teflon interpositional implants suggest an in vivo service life of only 3 years. Because no one has reported follow-up beyond 5 years, the long term performance and survival of any of these implants is doubtful. Asymptomatic patients should be evaluated yearly with tomography, CT, or MRI. Symptomatic patients should be evaluated every 4 to 6 months. Implant removal should be recommended if occlusal changes or condyle/fossa articular bone changes are active past the time of expected remodeling from surgery. This report summarizes the success/failure incidence from the literature and makes recommendations on follow-up, removal, and repair surgery.

Aluminum Oxide↗
PubMed1992

In vitro wear performance of Proplast TMJ disc implants.

This study investigates the in vitro wear performance of Proplast-Teflon Interpositional Implants (PTIPI; Vitek, Inc, Houston, TX), employing a mechanical TMJ simulator. Predictions of in vivo service life of PTIPIs are presented based on the in vitro wear testing data. Commonly employed laboratory testing methodologies are discussed in the development of alloplastic TMJ devices. Penetrative wear rates of the PTIPI at a 20-lb (9.1 kg) load were calculated to be 2.29 mm/100,000 cycles, yielding a predicted in vivo service life of PTIPIs of approximately 3 years. These results combined with reported clinical fate of this implant indicate that the intermediate- and long-term survival of this implant are uncertain.

Cartilage, Articular↗
PubMed1992

Prospective review of integral implants.

There are several factors that strongly correlate to HA-coated implant success and the prevention of implant morbidity. Surgical placement must be performed without compromise in technique. Implants placed into thin ridges or those that had dehiscence of their surface did not uniformly gain bone attachment levels during the healing period. Countersinking implants in extraction sites was critical; labial bone implant defects should be grafted with particulate HA. HA grafts to labial bone defects at the time of implant placement surgery are still short-term. Primary closure of all implant surgical sites prevented epithelial invagination into the surgical site and is associated with improved bone height around implants. Premature exposure of the implant during the healing period is associated with crestal bone loss. Loading forces should be physiologic, with maintenance of a physiologic equilibrium by a balanced restoration. Bone bulk should be created or preserved. Bone around implants may adversely respond to excessive loading forces. In the posterior maxilla, crestal bone loss has been observed that seems to result from excessive cantilever-type forces placed on the implants or from when implants are placed in the posterior mandible developed progressive bone loss that was associated with several factors. These factors included articulation against a natural occlusion, a horizontal ridge contour level with the external oblique ridge, a nonhygienic restoration, and the lack of keratinized gingiva against the abutment. Whether titanium implants develop progressive bone loss in the face of these factors is unknown. The presence of keratinized gingiva strongly correlated to bone maintenance in the posterior mandible. Because of this statistically significant finding, implant exposure should preserve all keratinized gingiva by transposing it labially to the implants. Most patients who receive implants for dental restoration have lost teeth because of caries and periodontal disease. The patient's behavioural patterns need to be redirected to maintain excellent oral hygiene in order to prevent peri-implant gingivitis. A hygienic restoration may be one of the most important factors associated with excellent implant health. Immediately upon receiving their restoration, patients did well maintaining their peri-implant hygiene. However, many patients do not continue their peri-implant hygiene. However, many patients do not continue their new hygiene methods and need to be strongly reminded to maintain their oral hygiene. Some patients do better than others. For some, a porcelain restoration with the restoration subgingival is well tended, but for others 4 to 5 mm of space needs to be established in order to prevent gingival problems.(ABSTRACT TRUNCATED AT 400 WORDS)

Dental Implantation, Endosseous↗
PubMed1991

Placement of endosseous implants into tooth extraction sites.

This study reports 4-year experiences with placement of hydroxylapatite-coated dental implants into extraction sites immediately after tooth extraction. Small defects present after implant placement were treated with dense, nonresorbable hydroxylapatite. Larger defects present after implant placement were treated with demineralized bone. Indications and contraindications for placement, as well as surgical techniques, are discussed.

Bone Resorption↗
PubMed1990

Factors associated with soft- and hard-tissue compromise of endosseous implants.

This prospective analysis identifies factors associated with endosseous implant removal as well as factors associated with implant morbidity resulting in nonscheduled patient visits. Treatment of the latter conditions is discussed. The most important factors identified for implant success were surgery without compromise in technique, placing implants into sound bone, avoiding thin bone or implant dehiscence at the time of implant placement, avoiding premature implant exposure during the healing period, establishing a balanced restoration, and insuring appropriate follow-up hygiene care. In the posterior mandible, the presence of keratinized gingiva was strongly correlated with optimal soft- and hard-tissue health.

Alveolar Process↗