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Biomedical subjects

J N Kent

Publications and source records attributed to J N Kent.

At least 55 records · Page 3Linked to original sources
PubMed1986

Hydroxylapatite blocks and particles as bone graft substitutes in orthognathic and reconstructive surgery.

A three-year clinical evaluation of 98 patients in whom dense hydroxylapatite in particle and block form had been placed in facial contour defects and osteotomy sites, and in cystic and reconstructive defects, alone or with autogenous bone, was conducted. The results indicate that the implants were effective in reducing operating time and potential for infection and relapse, as well as in reducing or eliminating the necessity of a donor site. The clinical response was excellent, and complications with both forms were minor, generally related to lack of initial fixation or failure to use autogenous bone in specific situations.

Bone Transplantation↗
PubMed1986

Reconstruction of the alveolar ridge with hydroxyapatite.

Diagnosis, classification, surgical and prosthetic techniques, supporting research, and clinical trials are described for reconstruction of the deficient alveolar ridge with dense, nonresorbable hydroxyapatite. The use of particulate and solid forms for preservation of the alveolar ridge, facial reconstruction, and orthognathic surgery are discussed.

Adult↗
PubMed1985

Hydroxylapatite reconstruction of alveolar ridge deficiency with an open mucosal flap technique.

A preliminary report on an open surgical technique for mandibular augmentation with hydroxylapatite has been presented. Twelve patients were evaluated from 2 to 20 months postoperatively. Advantages are thought to include better ridge form, maintenance of vestibular depth, and visualization of the mental nerve. In addition, splints usually are not necessary. Disadvantages include increased surgical time, possible lower lip inversion, and soft-tissue characteristics that may require secondary revisions.

Alveolar Ridge Augmentation↗
PubMed1985

Healing of mandibular ridge augmentations using hydroxylapatite with and without autogenous bone in dogs.

Dog mandibles were augmented with either hydroxylapatite (HA) alone or HA combined with autogenous bone. Within the limited time frame of this experiment (16 weeks) the group which received HA alone did not demonstrate the induction of bony ingrowth further than 1-2 mm into the augmented ridge. However, the animals augmented with HA combined with autogenous bone demonstrated an active, lamellar-type bony ingrowth, maturing bony haversian systems, and vascular elements forming throughout the entire area, extending to the overlying soft tissue interface. The clinical assessment of both types of augmented ridges (HA and HA and bone) were similar; both formed hard, firm ridges at approximately the same rate. This observation is consistent with human clinical experience with HA or HA mixed with bone. However,for patients who have severe mandibular atrophy and for whom increased mandibular bony bulk is crucial, a combination of HA and bone should be advantageous because of the increased extent of bony ingrowth.

Alveolar Ridge Augmentation↗
PubMed1985

Preservation of the alveolar ridge with hydroxylapatite tooth root substitutes.

A total of 49 patients, who were followed for 3 to 31 months, have had 92 hydroxylapatite root implants placed in fresh extraction sockets without soft tissue closure. Hydroxylapatite root implants maintain approximately twice as much alveolar bone as the contralateral control sites without implants. It is believed that this method is a more effective and efficient procedure to preserve alveolar bone for retention of dentures than previously described procedures.

Alveolar Process↗
PubMed1984

Alveolar ridge maintenance with solid nonporous hydroxylapatite root implants.

Animal studies were carried out to determine a simple technique of implantation of nonresorbable polycrystalline hydroxylapatite solid root forms and the biocompatibility of the material placed in fresh extraction sockets. An appropriately shaped root form was evaluated, and alveolar bone preservation was investigated in dogs and primates. It was found that bone and soft tissue would migrate across the HA root implant when placed 2 to 3 mm below the alveolar bone crest without soft-tissue closure. It was not necessary to use roots that fit the socket from the apex to the alveolar crest. An average of 2 mm more alveolar bone was preserved in fresh extraction sites as compared to control sites. The results of the animal studies indicated the appropriateness of a clinical trial in human beings.

Alveolar Process↗
PubMed1984

Proplast augmentation for posttraumatic zygomatic deficiency.

Facial deformities following fractures of the zygomatic complex are common. Included in this article are the indications, work-up, and surgical technique for placement of Proplast implant material to correct the deformity of the malunited zygomatic complex. Three cases are presented to illustrate this approach.

Accidents, Traffic↗
PubMed1984

A multicenter retrospective review of the mandibular staple bone plate.

The mandibular staple bone plate, herein referred to as the staple, has been used as a reconstructive device to improve mandibular function for more than a decade. This report presents the clinical and radiographic findings of a retrospective survey of 160 patients from three separate practices over an eight-year period (1975-1983). The criteria established at the 1978 NIH-Harvard Consensus Development Conference on Dental Implants were used to evaluate results. The study also evaluates experiences with other procedures used in conjunction with the staple.

Bone Plates↗
PubMed1984

Long-term radiographic evaluation of hydroxylapatite-augmented mandibular alveolar ridges.

From six months to four years after alveolar ridge augmentation was performed, the vertical ridge heights of 74 Class III and Class IV alveolar ridge deficiency patients, who had undergone augmentation with hydroxylapatite with or without autogenous cancellous bone, were measured using panoramic radiographs adjusted for magnification errors. No statistically significant decreases in vertical ridge heights were seen when only hydroxylapatite was used, nor were there significant differences between the two types of hydroxylapatite particles used. Unlike other bone onlay procedures, the use of autogenous bone and HA together did not result in significant decreases in vertical ridge height.

Alveolar Process↗
PubMed1984

Soft tissue responses to hydroxylapatite particles of different shapes.

Fifteen beagle dogs seven to 15 months of age had 0.5 g of hydroxylapatite in the form of sharp-edged particles (HA-1) or rounded particles (HA-2) implanted in buccal soft tissue pouches. Tissue specimens from each site were obtained at two weeks, six weeks, three months, and six months. A mild inflammatory response was seen at the implant sites with both particle shapes; however, inflammation resolved at a faster rate in the sites implanted with round hydroxylapatite particles.

Animals↗
PubMed1983

Quantitative histologic evaluation of LTI carbon, carbon-coated aluminum oxide and uncoated aluminum oxide dental implants.

The response of mandibular bone to identical geometry LTI carbon, carbon-coated aluminum oxide, and uncoated aluminum oxide blade-type dental implants in baboons for 2 years was evaluated using histologic, microradiographic, and scanning electron microscopic methods. In addition, a quantitative histologic analysis was performed identifying the type, amount, and distribution of tissue surrounding the dental implant systems. This is the final phase of a study investigating the effect of implant elastic modulus and implant surface chemical composition on the performance of dental implants. Previous studies have utilized clinical and radiographic evaluations, postretrieval mechanical testing, and finite element stress analysis to evaluate the dental implant performance. The results of the histologic study revealed a direct implant-bone interface with no intervening soft tissue in 16 of the 21 implants (76%). A fibrous tissue interface was observed in 5 of 21 implants (24%). Quantitative histologic results for the implants with a direct implant-bone interface showed statistically larger crestal cortical plates (p less than 0.05) and greater area fraction crestal cancellous bone (p less than 0.05) in the LTI carbon implant compared to the carbon-coated and uncoated aluminum oxide implants. The carbon-coated and uncoated aluminum oxide implants demonstrated statistically greater area fraction cancellous bone at the inferior region of the implant (p less than 0.05) and thinned and reduced crestal cortical plates when compared to the LTI carbon implants. The results indicate that significant stress shielding of the crestal bone had occurred with the rigid carbon-coated and uncoated aluminum oxide implants when compared to the LTI carbon implants which had a material elastic modulus similar to cortical bone. Based upon the histologic results, it appears that the LTI carbon implants with the direct implant-bone interface exhibited a greater potential for long-term successful performance compared to the aluminum oxide substrate implants.

Aluminum↗
PubMed1983

Late definitive correction of the orofacial cleft. Report of a case.

This article presents the results obtained through staged secondary reconstruction of a unilateral complete cleft of the lip and palates in a young male patient. In the case report the principles of orofacial cleft management are addressed, with specific reference to those points of immediate importance to the orthodontist and the surgeon, around whose synergistic efforts the final rehabilitation often must pivot. Orthopedic and surgical expansion of the scarred, constricted maxilla, orthodontic preparation and completion, maxillary advancement and alveolar cleft bone grafting, and the stabilizing roles of palatal scar release and bone grafts for the translated maxillary complex are discussed as the treatment plan is executed. Completing the rehabilitation are the integral considerations of speech and audiology, otologic surgical intervention, and soft-tissue revision of the lip and nose. The genesis of the secondary deformity is also explored relative to the primary congenital anomaly, the techniques and temporal sequence of its repair, and subsequent growth disturbance. A review of the pertinent literature is included.

Adolescent↗
PubMed1983

Prosthodontic management of the hydroxylapatite denture patient: a preliminary report.

A 4-year study and evaluation of nonresorbable hydroxylapatite to augment different alveolar ridges has been reported. The technique used resulted in improved contour, height, and width of the alveolar ridge. It was found that denture comfort improved with ridge augmentation as this allowed improved stability, support, and preservation of the ridge. Patient satisfaction was correlated to both surgical and prosthodontic success with the use of hydroxylapatite. The state and health of the tissues were found to be improved with the use of hydroxylapatite or hydroxylapatite and bone marrow. The prosthetic and surgical procedures were found to be easier to perform, and they produced more permanent and superior results than those previously experienced with only bone grafts and other alloplasts.

Adult↗
PubMed1983

Alveolar ridge augmentation using nonresorbable hydroxylapatite with or without autogenous cancellous bone.

A four-year prospective evaluation of the use of nonresorbable, particulate hydroxylapatite (HA) to augment deficient alveolar ridges was performed. The material was used alone and in combination with finely crushed autogenous cancellous bone. Implants were delivered subperiosteally by syringe injection, usually using local anesthesia for Class I to Class III ridges and general anesthesia for Class III and Class IV ridges. The improved ridge height and width were stable. Postoperative resorption with significant loss of ridge height, frequently seen with rib and iliac crest onlayed grafts, was not observed with HA augmentation. Permanent denture construction began as early as three weeks postoperatively and by four to six weeks if HA was combined with autogenous cancellous bone. It was possible to place mandibular staple implants simultaneously or following HA augmentation. Visor osteotomy techniques were improved by use of HA to produce a wider, more convex stable ridge. Although skin, mucosa, or dermal vestibuloplasties were performed as early as three months postoperatively in a small number of patients, there appeared to be a lesser need for vestibuloplasty after HA augmentation than after onlay bone grafting. In addition, prosthodontists performed fewer denture relines after HA augmentation than after onlay bone grafts. The authors believe the most significant factor accounting for these observations is the firm, nonmobile mucosal base resulting from augmentation with HA. The resultant stable, soft tissue base and improved ridge height and contour have contributed to a comfortable, retentive, stable denture for these patients. The prosthetic and surgical procedures are easier to perform and have produced superior, more permanent results than onlay bone grafts and alloplasts. Preliminary studies also point to exciting possibilities for use of HA as a bone substitute/marrow extender in maxillary and mandibular defects, cysts, and clefts and in osteotomies for orthognathic surgery.

Adult↗