Skeletal change at surgery as a predictor of long-term soft tissue profile change after mandibular advancement.

PURPOSE: This study examined the time course of hard and soft tissue changes after mandibular advancement surgery and the association between skeletal changes as a result of surgery and subsequent soft tissue changes. PATIENTS AND MATERIALS: Subjects were enrolled in a randomized clinical trial of rigid versus wire fixation after sagittal split ramus osteotomy, with cephalometric data obtained before orthodontics, immediately before surgery and at 8 weeks, 6 months, 1 year, and 2 years postsurgery. This early report describes changes in 20 Caucasian female subjects who had completed all phases of the study; these were not segregated by fixation method. Cephalometric changes were referenced to a cranial base coordinate system. Differences in soft and hard tissue changes among time intervals were examined using analysis of variance; the associations between immediate surgical change in chin landmarks and subsequent short- and long-term soft and hard tissue changes were examined using linear regression analysis. RESULTS: Soft and hard tissue mandibular structures were positioned anteriorly and inferiorly during surgery; the horizontal and vertical hard tissue mandibular changes were stable for 2 years after surgery (P > .30), as were the vertical soft tissue changes (P > .08). There was horizontal relapse of the lower lip and the inferior sulcus (P < .03) by 8 weeks; no horizontal relapse was detected in soft tissue chin points for up to 2 years after surgery. The time course of changes in osseous pogonion was more strongly predicted by the amount of surgical osseous chin change than were changes in soft tissue chin projection. CONCLUSIONS: Prediction of changes in soft tissue chin projection after mandibular advancement surgery is less certain as time from surgery increases and less certain than the prediction of changes in bony chin projection.

Morbidity from anterior ilium bone harvest. A comparative study of lateral versus medial surgical approach.

The morbidity of bone harvest was compared between anterior lateral and medial surgical approaches in a randomized prospective study. Forty consecutive patients, each requiring a minimum 40 cc of loose corticocancellous bone for maxillofacial reconstruction, were randomly placed into two equal groups. Morbidity vectors assessed included bone volume, blood loss, length of surgery, length of hospital stay, incidence of seroma, incidence of anterior thigh paresthesia, postoperative pain, and gait disturbance. The results demonstrated no significant difference in morbidity between these two approaches; therefore selection of either approach is the surgeon's personal preference. A thorough understanding of the osseous anatomy of the anterior ilium and its muscular attachments, a good surgical technique, an efficient surgical team, and a continuous flow of required surgical instruments are essential to reduce the morbidity of bone harvest.

Nerve sharing by an interpositional sural nerve graft between the great auricular and inferior alveolar nerve to restore lower lip sensation.

A case of bilateral nerve sharing via an autogenous sural nerve graft interposed between the ipsilateral great auricular nerve and the inferior alveolar nerve was used to restore sensation to the lower lip. To our knowledge this is the first report of successful nerve sharing between a sensory branch of the cervical plexus and the inferior alveolar nerve.

Changes of the hyoid bone and tongue following advancement of the mandible.

Little is known concerning the adaptation of the tongue and hyoid bone after surgical mandibular advancement. This study was undertaken to evaluate the relationship between tongue and hyoid bone posture and their adaptation following mandibular advancement in fourteen adults. The data indicate that (1) there is no statistically significant correlation between changes in the posture of the tongue and hyoid bone; (2) the hyoid bone returns toward its presurgical posture; and (3) the tongue assumes a new position relative to both the cranial base and the mandible. The changes in tongue position occurred immediately after surgery and persisted 2 years postoperatively.

Serious inferior alveolar nerve dysesthesia after endodontic procedure: report of three cases.

We have presented three cases of anesthesia and painful dysesthesia that occurred after the Sargenti technique was used in endodontic treatment of mandibular molars. Microsurgical techniques were used to alleviate painful causalgia and to restore functional sensation to the lower lip. The third patient refused treatment.

Results following simultaneous mobilization of the maxilla and mandible for the correction of dentofacial deformities: analysis of 100 consecutive patients.

One hundred consecutive cases were reviewed from two centers for correction of dentofacial deformities following simultaneous mobilization of the maxilla and mandible. The mean length of surgery was 5.15 hours, twenty patients received blood transfusions, and the mean length of hospitalization was 3.6 days. No patients experienced significant airway embarrassment requiring emergency procedures. An increased incidence of relapse, compared to single-jaw procedures, appears to be associated with these procedures. This study suggests that the simultaneous mobilization of both jaws should not be done without due consideration to specific indications and treatment planning. In select cases, with careful treatment planning, meticulous execution of surgical techniques, optimal supportive anesthesia, and postoperative care, the simultaneous mobilization of both the maxilla and the mandible can be achieved with few adverse sequelae and complications.

The relation between nasorespiratory function and dentofacial morphology: a review.

It is commonly assumed that nasorespiratory function can exert a dramatic effect upon the development of the dentofacial complex. Specifically, it has been stated that chronic nasal obstruction leads to mouth breathing, which causes altered tongue and mandibular positions. If this occurs during a period of active growth, the outcome is development of the "adenoid facies" (dentofacial morphology). Such patients characteristically manifest a vertically long lower third facial height, narrow alar bases, lip incompetence, a long and narrow maxillary arch, and a greater than normal mandibular plane angle. These dentofacial traits have repeatedly been attributed to restricted nasorespiratory function. It is generally believed that environmental factors can exert subtle or dramatic effects upon dentofacial morphology, depending upon their magnitude, duration, and time of occurrence. The purpose of this article is to present a critical review of the literature concerning the effect of one such environmental factor, nasal airway function, upon dentofacial morphogenesis. This review will critically examine the most frequently cited papers reporting a relationship between nasorespiratory function and dentofacial morphology. In summary, this critical review fails to support a consistent relationship between obstructed nasorespiratory function and the adenoid facies or long-face syndrome. Additional objective evaluations of this relation are encouraged.

Autorotation of the mandible: effect of surgical superior repositioning of the maxilla on mandibular resting posture.

Mandibular autorotation is a generally accepted cephalometric phenomenon that occurs when surgical superior repositioning of the maxilla is planned. This investigation was undertaken to determine whether autorotation of the mandible is a biologic phenomenon as well. Fifteen adults with vertical maxillary excess who underwent a mean surgical superior repositioning of 6.2 mm. were evaluated with cephalometric, kinesiometric, and electromyographic instrumentation immediately before and 3 months following surgery. Five persons selected at random from the original group (who also underwent a mean surgical superior repositioning of 6.2 mm.) were similarly evaluated 24 months following surgical intervention. The results of this study, which were analyzed by the Wilcoxon Matched-Pairs Signed-Rank test, revealed that a significant compensatory autorotation of the mandible occurred by the third month and was still constant 2 years later. We propose, on the basis of this preliminary evidence, that an "occlusal programming feedback mechanism" within the central nervous system mediated the compensatory autorotation of the mandible following surgical superior repositioning of the maxilla.

Musculoskeletal adaption to surgical advancement of the mandible.

This study was carried out in order to evaluate musculoskeletal adaption to surgical advancement of the deficient mandible. 10 adult individuals with mandibular deficiency were studied before and 3 months after surgical advancement of the mandible via lateral cephalometric radiography, kinesiometry, and electromyographic instrumentation. 10 adult controls were studied at the same intervals, but underwent no surgery. The data was entered into a DEC System-10 computer for morphometric comparison and statistical analysis. The results of this investigation demonstrate that musculoskeletal adaptions occur within the stomatognathic system following surgical advancement of the mandible. 3 months following surgery, the clinical and physiological rest positions of the mandible as well as the masticatory electromyographic activity were unchanged in both the control and the surgery groups. The rapid, functional adaptions that occurred in the surgery group are apparently due to changes in posterior ramus-mandibular body relations and neuromuscular adaption within the masticatory and suprahyoid musculature.