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Biomedical subjects

Jack W Martin

Publications and source records attributed to Jack W Martin.

16 recordsLinked to original sources

Fenretinide activity in retinoid-resistant oral leukoplakia.

PURPOSE: To test the hypothesis that the retinamide N-(4-hydroxyphenyl)retinamide (fenretinide) would be clinically active potentially via receptor-independent apoptosis and receptor-dependent effects in natural retinoid-resistant oral leukoplakia patients--the first test of this hypothesis in any in vivo setting. EXPERIMENTAL DESIGN: A phase II trial of fenretinide (200 mg/d for 3 months) in oral leukoplakia patients who had not responded (de novo resistance) or who had responded and then relapsed (acquired resistance) to previous treatment with natural retinoids. We analyzed apoptosis via the terminal deoxynucleotidyl transferase-mediated nick end labeling in situ DNA fragmentation assay. RESULTS: We accrued 35 evaluable patients with retinoid-resistant oral leukoplakia, 12 (34.3%) had partial responses to fenretinide (95% confidence interval, 19.2-52.4%), and response was associated with acquired resistance to natural retinoids (P = 0.015, Fisher's exact test). Nine responders progressed within 9 months of stopping fenretinide. Toxicity was minimal and compliance was excellent. Mean apoptosis values (SE) increased from 0.35% (0.25%) at baseline to 1.18% (0.64%) at 3 months (P = 0.001, sign test); this increase did not correlate with clinical response. The increases in 3-month mean serum concentrations of fenretinide (0.23 micromol/L) and N-(4-methoxyphenyl)retinamide (0.57 micromol/L) correlated with decreased retinol concentrations [Spearman correlation coefficient of -0.57 (P = 0.001) and -0.43 (P = 0.01), respectively]. CONCLUSIONS: Low-dose fenretinide was clinically active and produced a small increase in apoptosis in retinoid-resistant oral leukoplakia.

Adult↗

Mutans streptococci in xerostomic cancer patients after pilocarpine therapy: a pilot study.

OBJECTIVES: Opiod- and/or radiation-induced xerostomia in cancer patients is frequently associated with elevated levels of cariogenic mutans streptococci (MS). STUDY DESIGN: In a single-center, single blind 8-week clinical trial at The University of Texas M. D. Anderson Cancer Center, and from an initial sample of 32 patients, we evaluated MS counts in 28 cancer patients receiving chronic analgesic treatment for cancer pain. All patients received escalating doses of pilocarpine (Salagen) tablets, either 2.5 mg to 5 mg or 5 mg to 7.5 mg qid for 6 weeks, followed by placebo qid for a 2-week washout period. Whole resting saliva flow rates (g/5 min) and MS counts were evaluated at pretreatment, 3 weeks, 6 weeks, and 8 weeks. MS samples were obtained by 5-mL saline rinse (15 sec) at each visit prior to sialometry. RESULTS: In 19 patients (59%), MS counts exceeded 10(5) CFU/mL. At the end of the 6-week trial, 96% of patients showed a positive response to pilocarpine following a 30-minute postdosing evaluation (P=.001). MS counts were lower in 17 patients, higher in 6 patients, and nondetectable before and after pilocarpine in 5 patients (P=.03). CONCLUSION: The reduced MS counts associated with improved saliva flow rates following pilocarpine therapy in this short-term pilot study are encouraging, but further investigation in a larger group of patients over a longer study period is indicated.

Analgesics, Opioid↗

Facial prosthetic rehabilitation: preprosthetic surgical techniques and biomaterials.

PURPOSE OF REVIEW: Attention to detail ensuring a successful facial prosthetic rehabilitation must be considered a priority at the time of presurgery, surgery, and at every stage in fabricating the prosthesis. Teamwork between the surgeon and maxillofacial prosthodontist will ensure an optimal surgical preparation and definitive prosthesis. RECENT FINDINGS: Evidence of interaction between team members can most certainly be encouraging to the patient. During the prosthetic phase of treatment, focusing on tissue assessment, impression making, sculpting, mold fabrication, familiarity with materials, appreciation of color, delivery of instructions, and patient education will ensure a satisfactory outcome. With the desire, determination, and encouragement from the restorative team to make the most of this artificial replacement, a patient can have a higher quality of life and a more normalized lifestyle. SUMMARY: This review presents current concepts regarding facial prosthetic rehabilitation of patients with head and neck cancer and facial prosthetic biomaterials.

Biocompatible Materials↗

Treatment strategy for patients with ectodermal dysplasia: a case report.

Ectodermal dysplasia (ED) is a hereditary condition characterized by abnormal development of the skin, hair, nails, sweat glands, and the stomatognathic system. There are many different types of ectodermal dysplasia of which X-linked anhidrotic ectodermal dysplasia is the most common. Multiple genes have been discovered to cause ectodermal dysplasias. With any form of ED, children may display a range of symptoms and challenging rehabilitation. This clinical report presents the treatment plan for a young patient with ED and anodontia requiring prosthetic restoration.

Age Factors↗

Postsurgical use of prosthetic palatal appliances. Two case reports.

Patients with cleft lip or palate encounter a myriad of difficulties in their early years of life, some of which begin at birth. The defect often impairs suckling and deglutition in the neonate. It can hinder appropriate speech development and may impose undue social and psychological stresses. Surgical and orthodontic interventions are essential and prosthetic palatal appliances play an important role not only throughout the patient's treatment course, but also in the treatment of unfavorable surgical sequelae.

Child, Preschool↗

Randomized, double-blind, placebo-controlled phase IIb trial of the cyclooxygenase inhibitor ketorolac as an oral rinse in oropharyngeal leukoplakia.

PURPOSE: Nonselective cyclooxygenase (COX) inhibitors have been reported to decrease the frequency of upper aerodigestive cancers. Ketorolac tromethamine oral rinse has been shown to resolve another COX-dependent process, periodontal disease, without incurring gastrointestinal side effects. This trial evaluated if a topically delivered oral rinse containing ketorolac was as safe as and more effective than oral rinse alone in reducing the area of oral leukoplakia. EXPERIMENTAL DESIGN: 57 patients were randomized (2:1 ratio) in a double-blind, placebo-controlled study of ketorolac (10 ml of a 0.1% ketorolac rinse solution; n = 38) or placebo (10 ml of rinse solution; n = 19) given twice daily for 30 s over 90 days. Primary end point was evaluated visually obtaining bidimensional measurement of the size of leukoplakia lesion(s) at entry and at 90 days. Secondary end point was histological assessment of the leukoplakia as sampled by serial punch biopsy and independently reviewed by three pathologists. RESULTS: The patients included 67% males, 11% non-Caucasian, and 86% used tobacco with no significant differences between the two arms. Both rinses were well tolerated with good compliance, and there was no significant difference in adverse events (P = 0.27). Major response rate (complete response and partial response) was 30% for ketorolac and 32% for the placebo arm. There was no significant difference in change in histology between the two arms. CONCLUSION: Local delivery of a COX-containing oral rinse was well tolerated but produced no significant reduction in the extent of leukoplakia compared with the placebo. However, the favorable response rate to placebo arm remains unexplained and additional investigation of the tissue penetration with ketorolac is warranted.

Anti-Inflammatory Agents, Non-Steroidal↗

Radiation-induced xerostomia in patients with head and neck cancer: pathogenesis, impact on quality of life, and management.

BACKGROUND: Xerostomia is a common, debilitating complication of radiation therapy (RT) for head and neck cancer. This article reviews the pathogenesis of radiation-induced xerostomia, its impact on quality of life (QOL), and treatment options. METHODS: Virtually all patients undergoing RT for head and neck cancers have xerostomia, which causes oral discomfort and pain, increased dental caries and oral infection, and difficulty speaking and swallowing. This significantly impairs QOL and can compromise nutritional intake and continuity of cancer therapy. The literature describing pathogenesis, impact on QOL of radiation-induced xerostomia, and preventive and interventional therapies was reviewed. RESULTS: Current management strategies include stringent dental and oral hygiene; parotid-sparing radiation techniques to prevent or minimize xerostomia; and pharmacotherapies, such as salivary substitutes and sialogogues. Future strategies may include advanced three-dimensional intensity-modulated RT techniques, salivary gland transfer, newer sialogogues, and gene therapy. CONCLUSIONS: New treatment approaches to xerostomia from RT for head and neck cancer may result in significant improvement in patient QOL.

Head and Neck Neoplasms↗

Risk of osteoradionecrosis after extraction of impacted third molars in irradiated head and neck cancer patients.

PURPOSE: This study was performed to compare the risk of osteoradionecrosis (ORN) in head and neck cancer patients in whom 1 or more impacted third molars were extracted before radiotherapy with patients whose impacted third molars were left intact. PATIENTS AND METHODS: Eighty-one patients were selected from the medical records from 1989 to 1998. Patients had at least 1 impacted third molar and received radiotherapy for a head and neck cancer. These patients were divided into 2 groups on the basis of preirradiation extraction: group 1, patients who had impacted third molars extracted before radiotherapy (n = 55), and group 2, patients whose impacted third molars were left intact before radiotherapy (n = 38). In 12 patients of combined groups 1 and 2, at least 1 but not all of the impacted third molars were extracted before radiotherapy. RESULTS: Before radiotherapy, a total of 99 impacted third molars were extracted from the 55 patients in group 1 and a total of 55 impacted third molars were left intact in the 38 patients in group 2. After radiotherapy, a total of 7 impacted third molars were removed from 5 patients as treatment for infection (5 lower molars) or discomfort (2 upper molars). A total of 4 patients (2 from group 1 and 2 from group 2) developed ORN in the mandible. Of these 4 cases of ORN, 1 from group 1 appeared to be related to a dry socket that developed after preirradiation extraction of a lower impacted third molar, 1 from group 2 seemed to be related to infection of a lower impacted third molar after radiotherapy, and the remaining 2 cases appeared to be unrelated to an impacted third molar. CONCLUSION: Because few patients in this study developed ORN, the study failed to demonstrate whether preirradiation extraction versus retention of impacted third molars affects the risk for ORN.

Adolescent↗

Obturation of the partial soft palate defect.

A partially resected soft palate represents a more significant challenge for effective prosthodontic obturation than for complete soft palate resections. In fact, for some patients it may not be possible to prosthetically rehabilitate with partial soft palate resections, resulting in velopharyngeal dysfunction, which could include hypernasal voice quality and nasal regurgitation of food and liquids. This article presents a technique for recording the contours of a partial soft-palate defect for prosthetic obturation.

Denture Bases↗

In vitro effect of microwave irradiation on the retentive force of magnets.

STATEMENT OF PROBLEM: Few studies have addressed the possible effect(s) of microwave irradiation on the magnetic properties of "permanent" magnets during the fabrication of dental and maxillofacial prostheses. PURPOSE: The objective of this study was to investigate the influence of microwave irradiation energy on the retentive force of a magnetic attachment system used in maxillofacial prosthetic rehabilitation. MATERIAL AND METHODS: A heat-polymerized PMMA disk (6 cm in diameter) was fabricated. Seven magnets were placed around the wafer in a circumferential fashion: 1 in the center and 6 surrounding it. The 7 magnets were spaced 2 cm from their respective centers. Seven heat-polymerized PMMA cylinders were also used, and a magnet (counter-magnet) was placed in the center of each even with the cylinder's surface. Once the investment had set (45 minutes after mixing), the 7 counter-magnets in the cylinders were placed against the 7 magnets in the acrylic wafer. A second mixture of investment material was added. The flasks were separated, and the acrylic wafer was removed to accommodate the 7 counter-magnets in the base mold in the same geometric configuration and to serve as a "spacer" for the silicone material. A 1:1 mixture of medical grade elastomer (MDX4-4210) and medical adhesive silicone (type A) was packed and compressed, the molds were reclamped, and the excess silicone was removed. The elastomer/silicone wafer was packed and compressed into the test and base molds, the molds were reclamped, and excess silicone was removed. The first group of magnets, designated Group A, received microwave irradiation for 5 minutes at low power (112 W). This procedure was repeated for each group of magnets at the following polymerizing times (n=14): Group B, 10 minutes; Group C, 15 minutes; Group D, 20 minutes; Group E, 25 minutes; Group F, 30 minutes; and Group G, 35 minutes. Measurements of retentive force (N) at 10 mm/min ramp rate of speed of separation was conducted. The specimen rate read 5.0 points/second. Data were analyzed using a 1-way analysis of variance (alpha=.05); individual mean values were compared using the Tukey test (alpha=.05). RESULTS: There were no statistical differences in retentive force between groups D, E, and F (20, 25, and 30 minutes, respectively) or between groups A, B, C, D, F, and G (5, 10, 15, 20, 30, and 35 minutes, respectively). When the microwave-irradiated groups A through G were compared with the control group, there was a significant difference (P<.05) in retentive force (N). Group E (25 minutes) showed the largest reduction of retentive force (0.3 N, a reduction of 12%). CONCLUSION: If a prosthesis is processed using a microwave and contains samarium cobalt magnets, the retentive force may be reduced up to 12% under specific conditions.

Cobalt↗

Facial moulage: the effect of a retarder on compressive strength and working and setting times of irreversible hydrocolloid impression material.

STATEMENT OF PROBLEM: Irreversible hydrocolloid is widely used as an impression material for fabrication of extraoral maxillofacial impressions. A disadvantage of irreversible hydrocolloid, however, is its limited working time. PURPOSE: This study tested the compression strength (elastic recovery) and working and setting times for an irreversible hydrocolloid impression material after a retarder was added. MATERIAL AND METHODS: The irreversible hydrocolloid (Jeltrate) was mixed with water in a standard water/powder mixture of 18 mL (1 unit) of water and 7 g (1 unit) of the impression material. Test specimens (n = 3) were prepared by adding 2, 4, 6, and 8 drops of monobasic sodium phosphate (the retarder) to each. Three other specimens, to which no retarder was added, served as the control. Specimens were prepared according to the American National Standards Institute/American Dental Association's specification no.18 guidelines for irreversible hydrocolloid impression material. Immediately after the specimens were prepared, the flat end of a polished rod of poly(methyl methacrylate) was placed in contact with its exposed surface and quickly withdrawn. The working-time experiment was a pass/fail test conducted 30 seconds before the initial setting time. The initial setting time was established as extending from the start of the mix to the time when the impression material no longer adhered to the end of the rod. To determine how the compressive strength of the modified irreversible hydrocolloid (with retarder added) compared with that of the control, the mean stress at maximum load (Mpa) was analyzed. The compressive strength (MPa) was calculated. Statistical analysis consisted of descriptive statistics and regression analyses. RESULTS: The results of this experiment demonstrated that the elastic recovery of the irreversible hydrocolloid did not change with the addition of sodium phosphate (2 to 8 drops). The percent recovery with was 95.95% +/-.42%, 96.33% +/-.82%, and 96.28% +/-.53% for 0 (control), 2 and 8 drops, respectively. Average setting times for control specimens were 2 minutes 20 seconds +/- 0 seconds for the control specimen (0 drops) to 11 minutes 20 seconds +/- 1 minute 50 seconds for the test specimen with 8 drops. There was a direct relationship (R(2) = 0.85) between the number of drops added and the setting time. All control specimens and test specimens containing 2, 4, 6, and 8 drops of monobasic sodium phosphate produced acceptable levels of elastic recovery (> or =95%). CONCLUSION: Within the limitations of this study, predictable longer working and setting times were demonstrated for the irreversible hydrocolloid specimens with 1 to 8 drops of the sodium phosphate solution tested. The specimens with 8 drops of retarder solution exhibited variable setting times and would not be suitable for clinical use. The compressive strength of the modified irreversible hydrocolloid material tested was compromised because of the addition of sodium phosphate solution; however, recovery from deformation remained satisfactory as retarder solution was added.

Alginates↗

Custom modification of the Blom-Singer tracheostoma valve housing.

A technique is presented for modifying the Blom-Singer tracheostoma valve housing to improve peristomal skin adherence for hands-free tracheoesophageal speech production following total laryngectomy. The finished product is thin, flexible, and maintains enhanced tear strength. The edges of a standard housing device for the Blom-Singer valve are trimmed to allow for better accommodation to the tissue surface without distortion. A punch biopsy instrument is used to cut uniform holes around the housing device to allow for permeation of the silicone mixture for better mechanical adherence of the materials.

Adhesives↗

How I do it: a technique for oral wound irrigation following maxillectomy and mandibulectomy.

BACKGROUND: Numerous devices have been recommended for ensuring appropriate hygiene and care of wounds resulting from maxillectomy and mandibulectomy. This article describes an irrigation device for use in the oral cavity after these procedures. METHODS: The system consists of: a prepackaged, disposable, 50-cc piston syringe; a nonconductive connecting tube; and, a saliva ejector that can be assembled for oral irrigation. RESULTS: The modified piston syringe allows physicians, nurses, and patients to efficiently irrigate mucosal wounds, maxillary or mandibular defects, and oropharyngeal or oral and pharyngeal wounds. CONCLUSION: This system is efficacious, more adaptable, and less expensive than other self-irrigating gravimetic instruments and is thus recommended for use in patients who have undergone maxillectomy or other ablative procedures in the oral cavity.

Humans↗

Modification of the Barton button for tracheoesophageal speech: an innovative maxillofacial prosthetic technique.

Laryngectomized, tracheoesophageal speakers who achieve hands-free speech wear a special breathing valve to automatically shunt air into the pharyngoesophagus for speech production. The standard method of attachment is adherence to the peristomal skin with glues and adhesives. The Barton button is a simpler, more efficient alternative that provides intraluminal attachment within the trachea. Although the device is appealing, constraints in standard design and dimensions have limited its success. This article presents a technique for modification of the Barton button to increase its successful use by tracheoesophageal speakers.

Equipment Design↗

Anterior key method for indexing orbital prostheses.

This article describes a predictable method for indexing the ocular portion of an orbital prosthesis. Because indexing is performed from the anterior aspect of the cast, damage is minimized, fewer modifications are required, and the mold can be preserved for repeated use.

Acrylic Resins↗