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Biomedical subjects

W H Bell

Publications and source records attributed to W H Bell.

At least 91 records · Page 5Linked to original sources
PubMed1986

The effect of physical rehabilitation on mandibular function after ramus osteotomies.

The efficacy of a systematic regimen of rehabilitation of mandibular function after ramus osteotomy was investigated. Forty-eight patients who had had either sagittal split ramus osteotomy to advance the mandible or intraoral vertical ramus osteotomy to retract the mandible were studied; 24 patients received rehabilitation and 24 did not. Pre- and postsurgical maximal mandibular opening, lateral and protrusive mandibular movements, maximum bite force, muscle fatigability, and clinical evaluation of the temporomandibular joints were compared between the two groups. Patients who underwent an intraoral vertical ramus osteotomy did not show a significant decrease in any of the parameters measured whether or not rehabilitation was used. However, patients who underwent sagittal split ramus osteotomies without subsequent rehabilitation had significant decreases (P less than 0.05) in mean mandibular opening and bite force as well as increases (P less than 0.05) in muscular fatigability compared with patients who underwent rehabilitation. These findings indicate the need for routine preoperative evaluation of mandibular and temporomandibular joint function and postsurgical physical rehabilitation after ramus osteotomies.

Adult↗
PubMed1986

Wound healing associated with segmental total maxillary osteotomy.

A technique that maintains dual soft tissue pedicles to the palatal and labiobuccal areas in segmental total maxillary osteotomy was studied with respect to the effects on osseous revascularization and healing. Single-stage four-segment total maxillary osteotomies were performed by this method in five adult male rhesus monkeys. The animals were killed at intervals from immediately to 28 days after surgery. Histologic examination of the maxillae revealed that this technique is sufficient to support total maxillary osteotomy through 28 days. The soft tissue flap provided adequate blood supply to the anterior maxillary segment. All bony segments were mobilized, with only transient effects on bone healing and viability. The marginal osteonecrosis observed did not appear to be progressive. The effects of this procedure on the pulp are not clear.

Animals↗
PubMed1985

Wound healing after anterior and posterior subapical osteotomy.

Changes in the process of wound healing and in the dental pulp were examined following anterior and posterior mandibular subapical osteotomies in pig-tailed macaque monkeys. Results of microangiographic and histologic investigations indicated that degenerative pulpal changes may occur following mobilization and repositioning of small dentoalveolar segments. The potential significance of such degenerative pulpal changes and the need for routine dental radiographic checkups following anterior and posterior mandibular dentoalveolar surgery are discussed.

Alveolectomy↗
PubMed1984

Treatment of Class II deep bite by orthodontic and surgical means.

Conventional orthodontic correction of the Class II deep-bite deformity with a decreased lower anterior facial height tendency can be mechanically difficult, inefficient and, in many instances, impossible. Orthodontic treatment alone of either adults or adolescents with such deformities frequently can neither increase lower anterior facial height sufficiently to achieve ideal facial proportions nor achieve long-term occlusal stability. Despite the need for surgical intervention to achieve satisfactory occlusal and esthetic results, many patients with such deformities are still being treated in clinical practice by traditional orthodontic procedures, with less than ideal esthetic and/or occlusal results. The challenge to achieve efficient and stable treatment of this deformity has been met by the use of various surgical techniques in combination with orthodontic treatment. This combined surgical-orthodontic approach can provide increased treatment efficiency, long-term stability, and optimal esthetic results. The proper sequencing and correct selection of orthodontic mechanotherapy are essential to ensure the desired results. This article purposes to detail basic problems involved in diagnosis and treatment planning for the combined surgical-orthodontic approach to patients exhibiting Class II deep bite and decreased lower facial height. Orthodontic and surgical treatment objectives are explained, and representative case reports are presented and discussed to illustrate this method of treatment. Extraction patterns, control of the transverse dimension, arch wire selection, auxiliary wires, elastics, and extraoral appliance use are described. Surgically, the dentofacial disharmony associated with this deformity may defy treatment by surgical advancement of the mandible only. Genioplasty, Le Fort I osteotomy, symphyseal osteotomy, anterior or total mandibular subapical osteotomy, body osteotomy, submental lipectomy, and rhinoplasty are adjunctive procedures that are described and may be used in concert with mandibular advancement surgery.

Adult↗
PubMed1984

Hypomobility after maxillary and mandibular osteotomies.

A retrospective recall study of forty patients was made to examine mandibular function after orthognathic surgery. Maximum maxillomandibular opening, protrusion, and lateral excursions were measured and compared with similar mandibular movements in a control group of patients of comparable age. Six months to 42 months after maxillary and mandibular osteotomies, the majority of patients demonstrated decreased maxillomandibular opening compared to the control group 54.8 mm (SD 4.7). The decrease was most dramatic in patients previously treated with sagittal split ramus osteotomies. The mean maxillomandibular opening after Le Fort I osteotomy to reposition the maxilla superiorly was 48.7 mm (SD 5.7); after bilateral intraoral vertical ramus osteotomies to retract the mandible it was 48.6 mm (SD 5.7); and after bilateral sagittal split ramus osteotomies to advance the mandible it was 35.1 mm (SD 6.7). The presence of mandibular hypomobility after orthognathic surgery and maxillomandibular immobilization may be due to pre-existing or surgically induced muscle or temporomandibular joint dysfunction. Our findings indicate the need for routine clinical assessment of mandibular function preoperatively and for a systematic regimen of muscular and occlusal rehabilitation postsurgically to normalize muscle function, condylar movement, and range of mandibular motion.

Adult↗
PubMed1984

Changes in electromyographic activity following superior repositioning of the maxilla.

Surgical reduction of lower anterior facial height may alter several aspects of jaw muscle function. This study examined the biomechanics, electromyographic activity, and maximal bite forces in three patients manifesting vertical maxillary excess prior to and six months following superior repositioning of the maxilla. Reduction of lower anterior facial height by Le Fort I osteotomy tends to increase mechanical advantage of the jaw adductor muscles. It may also decrease muscle activity during isometric biting. It does not appear to alter the maximal isometric bite force.

Adolescent↗
PubMed1984

Histochemical study of the masseter muscle in patients with vertical maxillary excess.

This study was designed to examine the morphologic properties of the masseter muscle in individuals with vertical maxillary excess (VME). The deep surface of the anterior aspect of the superficial masseter was biopsied in nine patients at the time of corrective surgery. Individual muscle fibers were classified as slow-twitch-oxidative (SO), fast-twitch-oxidative-glycolytic (FOG), or fast-twitch-glycolytic (FG) based on staining characteristics using a battery of histochemical procedures. Most patients had normal tissue, although there were considerable differences in size and distribution of the three fiber types. Generally, SO fibers were the largest and most prevalent type of fiber. Two individuals, however, demonstrated evidence of muscle pathology that primarily affected the FG fiber population. Histochemical evidence of muscle pathology has not previously been reported in patients with VME, and the pattern of SO dominance observed in these patients may be different from the distribution that would be seen in the masseter of a person free of craniofacial deformities.

Adenosine Triphosphatases↗
PubMed1984

Soft tissue changes associated with advancement genioplasty performed concomitantly with superior repositioning of the maxilla.

A retrospective study of the osseous and soft tissue changes of the chins of ten patients treated for vertical maxillary excess by Le Fort I osteotomy and advancement genioplasty was undertaken. The patients were characterized by excessive lower anterior facial height, obtuse or normal nasolabial angles, prominent maxillary incisors, lip incompetence, everted lower lips, anterior open bites, lack of chin prominence, and excessive chin height. A change in the proportion of osseous to soft tissue of 1.0 to 0.87 was obtained by advancement genioplasty and concomitant superior repositioning of the maxilla by Le Fort I osteotomy.

Adolescent↗
PubMed1983

Combined surgical and orthodontic treatment of bimaxillary protrusion.

Bimaxillary protrusion can be treated effectively in growing patients and in adults with conventional orthodontic therapy. In the adult patient, however, combined surgical and orthodontic treatment modalities may offer distinct advantages over such conventional therapy. Treatment time and possible adverse effects of lengthy and extensive orthodontic therapy may be reduced and optimum esthetic improvement may be facilitated. Those cases that exhibit severe skeletal discrepancies in the vertical, transverse, or sagittal dimensions in addition to dentoalveolar protrusion may be best treated in this manner to simultaneously correct all existing problems and obtain optimal esthetic and functional results. This article delineates the rationale for such therapy and tridimensional diagnostic and treatment-planning considerations from both the orthodontic and surgical standpoints. Case reports illustrate clinically the results obtainable with such treatment.

Adult↗
PubMed1983

Muscular rehabilitation after orthognathic surgery.

There is both a biologic and a clinical foundation for the use of therapeutic exercise after othognathic surgical procedures to restore normal function of the jaw muscles. This can be accomplished by a systematic plan Of occlusal and muscular rehabilitation after release of maxillomandibular fixation. Through the diligent application of physical therapy principles, the function of the masticatory muscles can be more efficiently rehabilitated after orthognathic surgery and maxillomandibular fixation.

Dental Occlusion↗
PubMed1983

The versatility of genioplasty using a broad pedicle.

The biologic and clinical foundation for using a broad soft-tissue pedicle genioplasty technique is described. This technique is versatile and stable and produces more predictable soft-tissue changes than previously reported methods of altering chin contour with alloplastic implants. The broad pedicle genioplasty technique has clear advantages over other techniques for procedures such as secondary genioplasty using local anesthesia, concomitant genioplasty and anterior subapical osteotomy, simultaneous genioplasty and submental lipectomy, and segmentalization of the chin to facilitate narrowing or widening.

Adolescent↗
PubMed1981

Tridimensional planning for surgical/orthodontic treatment of mandibular excess.

The dentofacial deformity of mandibular excess is frequently complicated by significant discrepancies in the anteroposterior position of the maxilla and mandible. Disproportionality of facial height as a result of increased or decreased vertical growth of the jaws, labiomental contour, transverse arch relationships, and/or asymmetries also complicate this deformity. Planning treatment for mandibular prognathism must entail diagnostic consideration of all three dimensions of space if maximum results are to be obtained with contemporary surgical techniques. In this article some of these diagnostic considerations, pre- and postsurgical orthodontic objectives, surgical techniques, orthodontic sequencing, timing of treatment, and clinical results are delineated to acquaint the orthodontist with contemporary treatment planning for this deformity in order to obtain optimum function, esthetics, and relative stability. Tridimensional facial proportionality, occlusal balance, and good dental and skeletal stability were achieved in five patients (average age, 17.5 years) with relative or absolute mandibular prognathism. These patients, who were observed for an average postoperative follow-up period of 24 months, were treated by multiple maxillomandibular surgical procedures in concert with orthodontic treatment.

Adolescent↗
PubMed1981

Reduction genioplasty: surgical techniques and soft-tissue changes.

A retrospective study was made of the osseous and soft-tissue changes and clinical results after reduction genioplasty for correction of anteroposterior macrogenia in seven adults. The surgery was performed by a modified technique which maximized the soft-tissue attachment to the inferior and anteroinferior portions of the repositioned segment. The 0.58 ratio of soft-tissue to osseous change was greater than results reported in previous studies. The present article describes the anteroposterior reduction genioplasty technique and the clinical results achieved with its use.

Adolescent↗
PubMed1981

Correction of mandibular prognathism by mandibular setback and advancement genioplasty.

The goal of surgical-orthodontic treatment of mandibular prognathism is to achieve maximum function, esthetics and stability. These objectives were achieved in 10 adults who manifested a specific type of mandibular prognathism. The patient group under study, who manifested a relatively contour deficient chin and prominent lower lip, and class III malocclusion, was treated by orthodontics and mandibular setback in concert with advancement genioplasty. The advancement genioplasty technique was accomplished by maintaining as much soft tissue pedicle as possible to the repositioned chin. A near one-to-one ratio of soft tissue-to-osseous change was achieved in the patient group under study with the use of the described genioplasty technique in combination with mandibular setback by intraoral vertical ramus osteotomies.

Adult↗
PubMed1981

Soft tissue changes with combined mandibular setback and advancement genioplasty.

This study was designed to examine changes in soft tissue in six patients treated by advancement genioplasty combined with mandibular setback. The genioplasty technique was modified to keep a maximum amount of soft tissue attached to the repositioned genial segment. The group of patients was characterized by mandibular prognathism, a flattened labiomental sulcus, a prominent lower lip, and an apparent lack of chin prominence. The genioplasty consistently produced a 1:1 ratio of soft tissue change to advancement of the chin.

Adolescent↗
PubMed1981

Correction of vertical maxillary deficiency: stability and soft tissue changes.

Thirteen adults with vertical maxillary deficiency were treated by Le Fort I osteotomy and autogenous interpositional bone grafts to increase facial height. A retrospective cephalometric study of 11 of these patients showed that a consistent relapse of approximately 2 mm occurred, predominantly during the early postoperative period (two to three months). Thereafter, there was minimal positional change of the maxilla. The upper lip tended to lengthen a little. The amount of maxillary tooth exposure increased and improved the smile line and lip-to-tooth relationship. Future modifications of the surgical technique should be designed to maximize stability by improved methods of interosseous fixation during the critical early postoperative period, when much of the relapse occurs.

Adolescent↗