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Biomedical subjects

D E Waite

Publications and source records attributed to D E Waite.

At least 19 recordsLinked to original sources
PubMed1991

Cytotoxicity of amalgams, alloys, and their elements and phases.

The purpose of this study was to compare the relative cytotoxicity of amalgams, alloys, and their constituent elements and phases, by means of a rapid and sensitive in vitro cell culture test. Pure copper and zinc showed intensive cytotoxicity, significantly greater than that of pure silver and mercury. Pure tin was non-cytotoxic. The gamma-one phase (Ag2Hg3) revealed moderate cytotoxicity, which was significantly decreased by the addition of 1.5% and 5% Sn. However, the addition of 1.5% Zn to gamma 1 containing 1.5% Sn dramatically increased the cytotoxicity of gamma 1 to the same level as that of pure zinc. Whenever zinc was present in amalgams, higher cytotoxicity was revealed. High-copper amalgams showed the same cytotoxicity as a zinc-free low-copper amalgam. The addition of selenium did not reduce the cytotoxicity of amalgam. The cytotoxicity of amalgams was reduced after 24 h. The results of this study suggest that the major contributor to the cytotoxicity of alloy for amalgam is probably copper, while that for amalgam is zinc.

Copper↗
PubMed1991

Mandibular ramus anatomy as it relates to the medial osteotomy of the sagittal split ramus osteotomy.

The sagittal split ramus osteotomy is probably the most frequently used procedure for correction of mandibular skeletal dentofacial deformities. Despite numerous improvements in the technique in the 30 years since the procedure was introduced, a number of troublesome complications still occur. These include unfavorable fracture during surgery, paresthesia, and relapse. The purpose of this study was to determine where fusion of the buccal and lingual cortical plates occurs in the upper mandibular ramus, as it is thought that placement of the horizontal medial osteotomy above the point of fusion (without any intervening medullary bone) may lead to unfavorable fracture during splitting. Forty-nine human mandibles were sectioned vertically at three locations perpendicular to the surface of the ramus and the occlusal plane. Measurements were made to locate vertically the point of fusion of the buccal and lingual cortical plates relative to the lingula and to the depth of the sigmoid notch. The point of fusion occurred between 7.5 and 13.3 mm above the lingula. Only 2% of mandibles had fusion at or below the level of the lingula in the anterior ramus, whereas in the posterior ramus, 6.1% of mandibles were fused at that level. At a level halfway from the lingula to the sigmoid notch, 20% of mandibles were fused in the anterior ramus, whereas in the mid- to posterior ramus, the incidence was as high as 39%. The location of the medial horizontal osteotomy should be at or just above the tip of the lingula. A higher level of cut may be associated with an increased difficulty in splitting or incidence of unfavorable fracture.

Humans↗
PubMed1991

Mandibular anatomy as it relates to rigid fixation of the sagittal ramus split osteotomy.

Rigid fixation of osteotomy segments is frequently used to reduce relapse and allow for early mobilization of the mandible following the sagittal ramus split osteotomy. This study evaluated cortical bone thickness in the retromolar area of 49 human mandibles to determine if there is an advantage (in terms of cortical thickness) to placement of screws for rigid fixation at the external oblique ridge versus placement at the inferior border. The mandibles were sectioned vertically at three sites in the retromolar area, corresponding to the bone available for rigid fixation of the sagittal osteotomy. Cortical bone thickness was measured at the external oblique ridge and 5 mm above the inferior border. The buccal and lingual cortices were found to be significantly (P less than .001) thicker at the external oblique ridge than at the inferior border. This suggests that there may be an advantage in terms of stability to placement of internal fixation screws at the superior border.

Bone Screws↗
PubMed1990

Multicenter clinical trial of ibuprofen and acetaminophen in the treatment of postoperative dental pain.

Pharmacological management of pain for acute and chronic conditions has been guided by a scientific understanding of peripheral and central acting mechanisms for the control of inflammation as well as pain. Oral surgery pain is a reliable model to reference the effectiveness of commonly used analgesics such as ibuprofen and acetaminophen. A total of 706 patients who were experiencing moderate to severe pain received a single dose of ibuprofen, acetaminophen, or placebo. After 6 hours, the degree of pain relief and tolerance was assessed. Ibuprofen has important implications for postoperative pain in clinical practice.

Acetaminophen↗
PubMed1989

Overview and historical perspective of oral reconstructive surgery.

Pioneers in the field of dental reconstruction had little to offer their edentulous patients other than prostheses that were generally fitted without preparation or augmentation of the alveolar ridge. By the mid-1940s, the development of surgical procedures and the introduction of new materials offered significant advances. Increased denture retention was achieved by some implant methods and through use of the mandibular staple bone plate. Improvements in hydroxylapatite provided a material that could be used for alveolar ridge augmentation. It proved effective in limiting resorption and increasing attachment to soft and hard tissue. The recent development of purified fibrillar collagen in combination with hydroxylapatite enhances our ability to provide effective, long-lasting dental prostheses.

Dental Implants↗
PubMed1989

Correction of the deficient alveolar ridge.

The success of a denture is dependent on a good foundation; therefore, construction of the prosthesis begins with extraction of the teeth. The teeth should be maintained as long as possible if they can be restored. When the teeth are extracted, bone resorption usually starts, owing to systemic and local factors. Good communication between the prosthodontist and the oral and maxillofacial surgeon must exist during the diagnostic procedure, must be maintained through the various stages of treatment, and must prevail through the follow-up care of the patient. Each clinician must be aware of both the objectives and the possible limitations of the treatment the other will provide, to ensure optimal care for the edentulous patient. The development of the osteointegrated titanium implant system opens an exciting new avenue with respect to total rehabilitation of the edentulous patient. This is the future, and in our opinion, the preferred technique for mandibular reconstruction.

Aged↗
PubMed1988

Long-term evaluation of human teeth after Le Fort I osteotomy: a histologic and developmental study.

Transient pulpal vascular ischemia and direct injury to the apices of the teeth have been implicated as the causes of degenerative and atrophic pulpal changes in experimental animals after Le Fort I osteotomy despite the presence of collateral circulation. The long-term clinical effect of these pathologic changes in human teeth has not been studied. Seventeen maxillary third molar teeth from 10 patients whose postsurgical follow-up ranged from 6 months to 78 months (mean, 40 months) were extracted. The long-term biologic effects of Le Fort I osteotomy on the pulp and on the development of teeth were retrospectively evaluated with clinical and standard histologic techniques. Normal teeth from patients who were not operated on were used as controls. Histologic examination revealed an intact pulpal circulation and minimal pathologic changes in the pulpal tissue. Clinical and radiographic studies showed that the growing teeth developed normally after surgery. The Le Fort I downfracture procedure had little discernible long-term effect on the pulp and on the development of human third molar teeth.

Adolescent↗
PubMed1988

Collagen/hydroxylapatite implant for augmenting deficient alveolar ridges: twelve-month clinical data.

In a multicenter study, 77 edentulous patients had mandibular augmentation with implants of purified fibrillar collagen combined with dense hydroxylapatite (Alveoform Biograft); 22 of these patients also had maxillary augmentation. Most patients had Class III or IV mandibular atrophy, and had outpatient surgery with the subperiosteal tunneling technique. Temporary splints were worn for 24 hours post-surgery. Mean ridge height was 15.3 mm before surgery and 19.5 mm after 12 months, an augmentation of 4.2 mm. Predictable compaction occurred largely in the first few months after denture loading. Most patients, surgeons, and prosthodontists assessed the results of the procedure as good to excellent at 1 year following implantation. Adverse experiences, largely dehiscence and paresthesia, tended to resolve over time. Sera from ten patients demonstrated antibodies to bovine collagen that were not clinically significant. Alveolar augmentation with collagen/hydroxylapatite achieved clinically significant results that compared favorably with those achieved with other types of ceramic implants.

Adult↗
PubMed1988

Tomographic evaluation of temporomandibular joints following discoplasty or placement of polytetrafluoroethylene implants.

A retrospective comparison was made of tomographic change in the temporomandibular joint (TMJ) of patients who had been treated by either discoplasty or discectomy with polytetrafluoroethylene (PTFE) disc replacement. Fifty-five PTFE- and 18 discoplasty-treated joints were evaluated. More than 60% of the PTFE-treated joints showed severe, destructive osseous change, whereas none of the discoplasty joints showed such change. Histologic examination of the tissues surrounding removed PTFE implants showed a foreign body giant cell reaction. The severity of radiographic change raises questions about the propriety of PTFE as a disc replacement material.

Adolescent↗
PubMed1987

Evaluation of collagen/hydroxylapatite for augmenting deficient alveolar ridges: a preliminary report.

A multicenter study was undertaken to evaluate a new alveolar ridge augmentation material composed of purified fibrillar collagen and particulate hydroxylapatite (PFC/HA). In a study of 77 patients and 99 reconstructed ridges, this material provided superior handling properties over HA alone as evidenced by its ease of surgical placement and manipulation, and the rarity of particle migration or displacement. Moreover, the rapid development of ridge firmness and stability allowed for the loading of dentures within three to six weeks. Prosthodontist evaluations and surveys of patient satisfaction showed great satisfaction with denture fit, comfort, esthetics, speech, and ability to masticate.

Adult↗
PubMed1986

Effects of temperature on blood flow in facial tissues.

This study evaluated the effect of temperature on blood flow by using rubidium 86 to determine the fraction of cardiac output going to specific facial tissues of rats. Seventy-seven male Holtzman rats were divided into two groups and various subgroups. The intraoral subgroups were categorized according to the temperature of the water irrigating the oral cavity (11 degrees, 39 degrees, 41 degrees, 43 degrees, or 45 degrees C). The extraoral subgroups were categorized according to whether heat or ice was applied to the cheek of the rats and the duration of application (10 or 20 minutes). Rats were killed within 60 seconds after injection of 86Rb, and tissue samples were taken from the buccal mucosa, facial skin, masseter muscle, mandible, tongue, and maxilla. The fraction of isotope uptake in each gram of these tissues (FU/g) was then calculated. For the intraoral group, the bath temperature of 39 degrees C increased the FU/g in all tissues except masseter muscle and tongue. Higher bath temperature did not further alter the FU/g. Lowering the temperature to 11 degrees C changed the FU/g significantly only in the tongue. For the extraoral group, 20-minute application of ice was required to reduce FU/g significantly in all tissues but masseter muscle and skin. Extraoral heat application for 10 minutes increased FU/g significantly in skin and tongue, but no further change was seen after 20 minutes of application.

Animals↗
PubMed1986

Repair of alveolar cleft defects with autogenous bone grafting: periodontal evaluation.

Twenty-six patients with cleft lip and palate (18 with unilateral and eight with bilateral clefts) with 34 canines that had erupted through grafted alveolar cleft defects were studied to evaluate their periodontal status. The results were compared with 58 canines erupted through a normal alveolus in 29 noncleft control patients. The overall periodontal status revealed a higher plaque index in the patients with cleft compared to the orthodontic control patients, but parameters of gingival index, probing depth, and attachment loss had no significant differences between these groups. The cleft-associated canines had more than 90 percent of their possible clinical attachment levels intact at the examination. This indicated that grafting of these alveolar cleft defects resulted in a clinically satisfactory periodontium to support these canines as they erupted through the osseous grafts for periods of at least 2 to 8 years following surgery.

Adolescent↗
PubMed1985

Effects on the periodontium of vertical bone cutting for segmental osteotomy.

The periodontal response to vertical osteotomy was evaluated in seven males and ten females, aged 14-45 years (mean 26.8), who were scheduled for maxillary and/or mandibular segmental osteotomies. Plaque and gingival indices, pocket depth, clinical attachment level, width of attached gingiva, and osseous support were recorded from teeth adjacent to each osteotomy site prior to and from six months to three years after surgery. In each patient teeth numbers 3, 9, 13, 19, 25, and 29 were used as controls. There was no significant (P less than or equal to 0.05) difference between experimental and control teeth with respect to plaque, gingivitis, pocket depth, or clinical attachment level. Slightly decreased osseous support and width of attached gingiva were found adjacent to osteotomy sites. However, although these decreases were statistically significant (P = 0.005), they were not clinically very large. It was concluded that segmental osteotomies, in general, may be performed without producing significant changes in the periodontal structures.

Adolescent↗
PubMed1985

A primate model for producing experimental alveolar cleft defects.

A simplified surgical technique to create an alveolar cleft defect with oronasal communication was developed in 12 female rhesus monkeys. The defects fulfilled the following criteria: 1) a bilateral alveolar cleft with a minimal width of 1 cm; 2) presence of an oronasal communication lined by epithelium; 3) absence of any clinical signs of inflammation within the cleft defect area; and 4) presence of functional teeth on each side of the created defect.

Acrylic Resins↗
PubMed1984

Periodontal evaluation of canines erupted through grafted alveolar cleft defects.

Two to eight years after receiving autogenous iliac crest grafts for treatment of alveolar cleft defects, eighteen patients who had unilateral cleft palate were evaluated for their periodontal status. When cleft-associated canines were compared with contralateral control canines, no statistically significant differences were found between specific surface values for plaque index, gingival index, or probing depths. Attachment loss was found to be greater (less than 0.72 mm) on the mesio-facial, facial, and mesio-palatal surfaces of the cleft-associated canines than on the control canines. Fifty-six per cent of the cleft-associated canines required surgical exposure and 44% also required orthodontic assistance to erupt to a functional occlusion. Osseous grafting of alveolar cleft defects resulted in satisfactory clinical periodontal support for cleft-associated canines.

Adolescent↗
PubMed1984

Hemangiopericytoma of the tongue: report of case.

A case of hemangiopericytoma of the tongue is reported. A comprehensive literature review regarding hemangiopericytoma of the tongue has been presented. Only ten cases of hemangiopericytoma of the tongue have been reported in the literature, including the present case, a 29-year-old male.

Adult↗