PubMed HealthSearch

Biomedical subjects

R F Jacob

Publications and source records attributed to R F Jacob.

At least 19 recordsLinked to original sources

Partial denture framework design for bone-grafted mandibles restored with osseointegrated implants.

Unilateral osseous reconstruction of a dentate mandible after tumor ablation may be restored with implants and a removable partial denture. Often the remaining dentition is in a "straight line" that does not allow cross-arch stabilization of the framework. Framework design incorporating existing unilateral lingual or buccal retention in the natural dentition and unilateral implant attachments affords a stable, retentive definitive prosthesis for this patient population.

Acrylic Resins

Mandible fragment fixation during reconstruction: the splint-and-plate technique.

One of the most popular methods of mandible fragment fixation is the precontoured reconstruction plate technique. Unfortunately, this method is not a reliable option when tumor distorts the mandibular contour or extends through the buccal cortex of the mandible. An alternative to the precontoured reconstruction plate is the splint-and-plate technique of mandible fragment fixation. An application of this appliance and method in 10 patients revealed the technique's advantages. The splint can be applied quickly and does not obstruct the ablative or reconstructive procedure. Further, the splint accurately keys the dentition and reliably maintains temporomandibular joint relationships. Finally, this technique provides a reference point to the exact position of the symphysis and angle when these landmarks have been resected.

Adult

Management of xerostomia in the irradiated patient.

Symptomatic management of xerostomia in the head and neck radiation patient often is a palliative process at best. There are secondary clinical effects, however, that require definitive management. Use of fluorides, antimicrobial rinses, saliva substitutes, and sialagogues is discussed.

Head and Neck Neoplasms

Duplication of interim speech aid for definitive impression tray fabrication.

A wax tray is stable and easily relieved if overextended. Unusual tray undercuts or angles needed for the partial resection patient need not be eliminated before the impression procedure. Relief of these undercuts is necessary with acrylic resin trays to ensure separation from the final stone cast. Because the wax tray is separated easily from the prosthesis during the boil-out, it is not necessary to "burn" or grind acrylic resin from the framework. The tray shape is duplicated from the existing interim prosthesis on the nasopharyngeal and oropharyngeal side. An arbitrarily shaped acrylic resin tray may be grossly overextended and require time-consuming clinical adjustments. An underextended tray on the nasopharyngeal side will not carry or support the impression material around or through the residual soft palate remnant. A tray that closely approximates the final prosthesis will allow use of a tissue conditioner final impression without need for border molding (Fig. 2). Duplicating the oropharyngeal side of the interim speech aid duplicates the previously established plane that is compatible with the tongue. The author has used this technique successfully for eight total and five partial soft palate resections. A cleft palate speech aid prosthesis has also been made with this technique.

Denture Design

Mandibular restoration in the cancer patient: microvascular surgery and implant prostheses.

This article deals with state of the art reconstruction and rehabilitation of the head and neck cancer patient who requires mandibular resection. The mandible can be reconstructed by microvascular free tissue transfer of bone and soft tissue from distant body sites. The dental units and missing soft tissue contours can be supported by osseointegrated implants placed in the grafted bone. This article discusses the rationale for patient selection and sequencing of this complex and rewarding rehabilitation.

Dental Implants

Processed record bases for the edentulous maxillofacial patient.

Use of processed record bases to register edentulous jaw records offers increased accuracy in final prostheses occlusion. Processed bases for the maxillofacial patient following resection of the maxillae or mandible also improve the reliability of the jaw relation record. Because of the unusual paths of insertion and tissue undercuts within the surgical defect, block-out of trial record bases on the master cast can result in gross instability of the bases. Errors in occlusion, esthetics, lip support, and buccolingual tooth placement can be minimized with processed bases.

Denture Bases

Indirect retainers in soft palate obturator design.

Definitive framework design for the maxillofacial patient with complete maxillary dentition who has had a soft palate resection requires the use of direct and indirect retainers. It is possible to retain these prostheses, however, with only two posterior clasps and indirect retainers without clasps. This design offers an esthetic, retentive, and functional restoration while preserving existing structures. Four clinical applications are described.

Denture Design

Electrotherapy and hyperbaric oxygen: promising treatments for postradiation complications.

Electrotherapy and hyperbaric oxygen therapy have been added to physical therapy to treat patients with postsurgery and radiation sequelae. Problems of reduced oral opening and range of head movement, soft tissue necrosis, osteoradionecrosis, and delayed wound healing were addressed in 37 patients over a 3-year period. Of this group, 16 irradiated maxillary resection patients were specifically followed up to determine the effectiveness of the new modalities on improving reduced oral opening. Although healing and the quality of the soft tissues showed marked improvement there was no significant improvement in oral opening.

Acupuncture Therapy

Physical therapy techniques in the treatment of the head and neck patient.

Limited jaw openings, which may develop following surgery and radiation therapy is a significant clinical problem. Some patients develop restricted oral opening because of extensive fibrosis and scarring of the affected tissues. The aid of the physical therapist is invaluable in the treatment of these patients.

Head and Neck Neoplasms

Postglossectomy deglutitory and articulatory rehabilitation with palatal augmentation prostheses.

For patients who may have significantly impaired deglutitory and articulatory functions after glossectomy, an important aspect of the rehabilitative management in our institution is the use of palatal augmentation prostheses. The aim is to reduce the free space between the roof and floor of the oral cavity to permit stronger lingual propulsion during oral deglutition and better linguopalatal contact during articulation. We evaluated ten patients who received this device after glossectomy during the past two years. Modified barium swallows and voice recordings were performed when possible with and without the use of the palatal augmentation prosthesis. Articulatory and deglutitory functions were evaluated on a scaled score ranging from 0 to 10 points. The scores of the patients' average immediate improvements were 4.5 points (range, 2 to 7) for articulation and 3.5 points (range, 2 to 7) for deglutition; the scores of average long-term improvements were 3.4 points (range, 2 to 7) and 2.2 points (range, 6 to 8), respectively. Patients using the palatal augmentation prosthesis experienced significant improvement in both functions. We believe that this device contributes greatly to rehabilitative therapy for patients who have undergone extirpative surgery for tumors of the oral cavity.

Aged

Backscatter radiation at bone-titanium interface from high-energy X and gamma rays.

Occasionally head and neck cancer patients treated with high-energy X rays and gamma rays have titanium metal dental implants in their maxillae or mandibles. The resulting effect of the bone-metal interface on the radiation dose is of interest. Ionization measurements for 60Co gamma rays and 6 MV and 25 MV X rays were made. A thin-window parallel-plate chamber was used to determine the magnitude of the dose enhancement that was due to the backscattered electrons from titanium. The results showed that for 60Co there is a 15% increase in dose to solid bone at the entrance side of the titanium. For higher energy X rays, the increase in dose was about the same or slightly lower than for 60Co. Monte Carlo calculations substantiated the measurements. This increase in dose fell off rapidly and became negligible at 1-2 mm from the interface. This backscattered dose should be taken into account when planning radiation therapy treatment for patients with dental implants.

Bone and Bones

Postmortem identification of the edentulous deceased: denture tissue surface anatomy.

This model evaluates the use of dental stone casts derived from maxillary tissues and from the internal aspects of maxillary dentures for edentulous postmortem identification. Tissue topography of the total cast and of rugae tracings photographed from the casts were evaluated for identification accuracy in twenty-eight trials for each of the two designs. Eight casts were examined in each trial. The trial was designed as matching or nonmatching, and as an equivocal or unequivocal decision by the examiner. Unequivocal decisions with 100% accuracy resulted when the entire dental cast was evaluated. Seventy-nine percent accuracy with equivocation in some trials resulted when only rugae tracings from the casts were evaluated. This investigation supported use of stone casts derived from the internal anatomy of maxillary dentures for forensic science identification when cast topography in toto was considered.

Adult