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Biomedical subjects

D P Sinn

Publications and source records attributed to D P Sinn.

At least 19 recordsLinked to original sources
PubMed2001

Integration of the medical degree in oral and maxillofacial surgery: A 10-year follow-up.

PURPOSE: Ten years ago, the American Association of Oral and Maxillofacial Surgeons membership was surveyed to evaluate the influence that integration of a medical degree might have on oral and maxillofacial training. The intent of the current survey was to reassess the influence a medical degree has had on the specialty over the past 10 years. PATIENTS AND METHODS: The effects of a medical degree on privileges, referral patterns, and its role in the office, hospital, and academic settings were studied. Biographical data was collected and responses were evaluated for the following groups: 1) the nation as a whole, 2) MD versus non-MD oral and maxillofacial surgeons (OMS), 3) geographic regions of practice, 4) population, 5) number of years in practice, and 6) involvement in academic programs. RESULTS: The results of this survey were similar to the previous one. Substantially different responses were seen between the dual-degree and single-degree OMS as well as differences between geographic locations, years in practice, and academic involvement. MD-DDS and academic OMS again possessed a broader spectrum of privileges than their colleagues. Recently trained OMS again possessed a greater number of privileges than more experienced surgeons. CONCLUSION: Overall there has been a trend toward increasing surgical privileges over the past 10 years for both single- and dual-degree OMS. The results presented emphasize the need to continually assess the influence that a medical degree has on the specialty.

Credentialing↗
PubMed2000

Tension forces in relation to LeFort III osteotomies.

Complications associated with LeFort III osteotomies have led to modifications of the procedure. Attempts to decrease morbidity include performing incomplete osteotomies or eliminating pterygomaxillary dysjunction. The purpose of this study was to determine the amount of tension required for separation of the midface from the pterygoid plates and to observe the fracture patterns. An Instron machine (Instron Corporation, Canton, MA) was used to measure the tension forces in 16 cadaver skulls divided into five groups. The groups varied as to whether the osteotomies were complete and whether pterygomaxillary separation was performed. Specimens with incomplete osteotomies and without pterygomaxillary separation required greater tension forces for separation and exhibited a high percentage (47%) of unfavorable fractures. Because high amounts of tension are required leading to unpredictable separations, we recommend complete osteotomies with pterygomaxillary dysjunction when performing LeFort III osteotomies.

Dental Stress Analysis↗
PubMed1999

Mandibular distraction osteogenesis with multidirectional extraoral distraction device in hemifacial microsomia patients: three-dimensional treatment planning, prediction tracings, and case outcomes.

Distraction osteogenesis of the craniofacial skeleton with the use of several different types of distraction devices (i.e., extraoral, intraoral, unidirectional, multidirectional, and customized) have been documented. However, the details of treatment planning and the method of predicting the distraction of the mandible in patients with hemifacial microsomia have not been published previously. This paper presents a technique for (1) three-dimensional treatment planning for mandibular distraction, (2) three-dimensional prediction tracings with conventional radiographs (panoramic, lateral, and posterior-anterior cephalometric), and (3) correlating the treatment planning and clinical applications. Lastly, 2 patients with hemifacial microsomia planned and treated with this approach are reported.

Adolescent↗
PubMed1999

Transoral maxillary distraction osteogenesis of an unrepaired bilateral alveolar cleft.

Distraction osteogenesis has gained acceptance as a viable modality for lengthening hypoplastic skeletal structures in the maxillofacial region. A case of the application of this technique to advance the maxilla in an unrepaired bilateral alveolar cleft via a transoral approach is presented. The distraction devices were applied bilaterally to the zygomatic buttress region with the activating arms protruding from the oral cavity. A high Le Fort I osteotomy was performed under general anesthesia and, prior to distraction, the three maxillary segments were unified with an occlusal acrylic splint. Activation was begun 6 days after placement, at a rate of 1 mm per day, until the planned maxillary advancement had been achieved. An 8-week period of consolidation was allowed prior to removal of the devices.

Alveoloplasty↗
PubMed1998

Surgical outcomes using bioabsorbable plating systems in pediatric craniofacial surgery.

The purpose of this study was to evaluate the surgical outcomes of the 1.5-mm LactoSorb plating system (Walter Lorenz Surgical, Inc., Jacksonville, FL, U.S.A.) used to stabilize the osteotomized calvarial bone in pediatric patients who have undergone craniofacial surgery. The records of 33 consecutive pediatric patients who underwent craniofacial surgery from January 1997 through December 1997 were reviewed. There were 18 male and 15 female patients, and the age ranged from 4 months to 12 years. Patients were followed-up at 1 week, 1 month, 3 months, 6 months, and 12 months after surgery. For those patients reviewed, the following information is included: age, sex, diagnosis, surgical procedures, number and size of LactoSorb plates and screws used in each patient, operative difficulty of the screws and the heat pack, and postoperative complications, including wound healing, palpability, and infection. The LactoSorb plating system was used to stabilize the osteotomized calvarial bones in 33 patients who were diagnosed with: 1) craniosynostosis, 2) hydrocephalus, 3) fibrous dysplasia, or 4) cranial deformation. Orbital rim advancement and anterior cranial vault reshaping were performed in 17 patients. Posterior cranial vault reshaping, orbital rim advancement, and anterior cranial vault reshaping were performed in eight patients. Posterior cranial vault reshaping only was performed in seven patients. Excision of fibrous dysplasia from temporal bone was performed in one patient. One patient had a postoperative wound infection, and LactoSorb plates were palpable postoperatively in four patients. The LactoSorb plating system provided adequate rigidity for stabilizing the osteotomized calvarial bone during surgery and maintained adequate rigidity after surgery during the bone healing period before absorption. This plating system showed satisfactory results in pediatric craniofacial surgery patients.

Absorbable Implants↗
PubMed1998

Fever after craniofacial surgery in the infant under 24 months of age.

A retrospective review was undertaken of 126 consecutive craniofacial procedures involving a transcranial component, performed at the Children's Medical Center at Dallas, between 1990 and 1994. Standard postoperative axillary temperature measurements were recorded until discharge. Age at surgery of less than 24 months correlated very strongly with a postoperative temperature of greater than 38 degrees C (r = -0.92). The incidence of postoperative fever was high in all age groups, yet there was still a significant difference between the group younger than 2 years and the group in which surgery was performed after the age of 2 years across all postoperative temperature ranges, from >38 degrees C to >39.5 degrees C (p < 0.001, chi-square test). The white blood cell count was elevated above the age-related normal in 67 percent of febrile patients. There was no correlation between type or duration of surgical procedure, length of intensive care or hospital stay, or the need for blood transfusion and the development of a significant postoperative fever. There were minor infectious complications in four patients (3 percent), only one of which was a wound problem related to the surgery. All infectious complications were easily identifiable clinically. There was no mortality or serious infections. The development of postoperative fever, and an elevated white blood cell count, is to be expected in pediatric patients undergoing craniofacial procedures. The routine laboratory investigation of postoperative fever in pediatric craniofacial patients under 2 years of age without procedures involving transgression of the paranasal sinuses is not warranted unless there are associated clinical indicators.

Age Factors↗
PubMed1997

Comparison of habitual masticatory patterns in men and women using a custom computer program.

STATEMENT OF PROBLEM: Though computer-based systems for recording three-dimensional jaw motion and muscle activity during mastication are common, few computer programs are available to analyze the resultant data. Few studies have discussed the variability over time of the many parameters of the masticatory cycle now measurable by computer systems. PURPOSE: The purposes of this study were to (1) use a custom computer program, (MAS), for analysis of long-term repeated measurements of mandibular motion and muscle activity; (2) determine sex differences for mandibular movements and activity of the muscles involved during mastication; and (3) determine the variability over time and the statistical power of these methods. MATERIALS AND METHODS: Masticatory cycles of 20 normal men and 17 normal women were examined during mastication of a constant bolus at a sampling rate of 500 fps. Measurements included duration of chewing cycle and its component phases, mandibular displacement in three dimensions, and electromyographic activity in the temporalis and masseter muscles. The MAS custom computer program was used for analysis. Two-way repeated measures analysis of variance was used to compare the men with the women over three trials at 0, 6, and 12 months. The variability over time associated with each measurement was also estimated. RESULTS: Timing of the phases of the chewing cycle were most repeatable between trials, whereas lateral excursions and muscle force magnitudes were the least repeatable measures. Durations of total cycle, its slow-open and fast-close phases, were significantly longer for the female group, and their bursts of muscle activity tended to be longer. The amount of vertical mandibular excursion tended to be greater for men. There were no gender-related differences in the amplitude of muscle activity. CONCLUSIONS: This study demonstrated that men have significantly shorter chewing cycles with faster velocities than women. Men used significantly greater chewing force than women, although their electromyographic activity levels were equivalent. The masticatory measurements made by the MAS program had differing amounts of variation over time. Total duration of the chewing cycle and amount of opening varied the least, whereas amount of lateral excursion and jaw muscle electromyographic magnitudes exhibited the greatest variation.

Adult↗
PubMed1997

Functional and morphologic alterations after anterior or inferior repositioning of the maxilla.

PURPOSE: The purpose of this investigation was 1) to compare functional and morphologic measurements between controls and patients scheduled for anterior or inferior repositioning of the maxilla, and 2) to examine how these patients' oral function adapted after surgery. PATIENTS AND METHODS: Nine male patients undergoing anterior and/or inferior repositioning of the maxilla were compared with 26 male controls preoperatively and up to 3 years after surgery. Measures of skeletal morphology, mandibular range of motion, maximum voluntary bite force, and levels of electromyographic (EMG) activity in the anterior and posterior temporalis and masseter muscles during isometric bites were made on all subjects over time. One-way ANOVA was used to compare the controls, the patients before surgery, and the patients after surgery. RESULTS: Before surgery, most of the patients had morphologic characteristics of mandibular prognathism and maxillary retrognathism. Surgery made the patients' skeletal morphology similar to controls except for mandibular length, upper facial height, and palatal plane angle, which were significantly greater than those of controls. There were no significant differences in jaw muscle mechanical advantage between controls and patients either before or after surgery. Hypomobility of the jaw was apparent at 6 weeks and 6 months after surgery, but returned to normal values within 1 to 2 years. Before surgery, the patients had maximum voluntary bite forces significantly less than those of controls. Bite forces in patients steadily increased after surgery, approaching significantly higher values than those of controls. Before surgery, patients' muscle activity levels per unit of bite force were not significantly different from those of controls. Most of the patients' muscle activity levels per unit of bite forces at all bite positions showed no significant change after surgery. CONCLUSIONS: The results of this study suggest that anterior or inferior repositioning of maxilla produces some significant functional benefits in patients.

Adult↗
PubMed1997

Comparison of habitual masticatory cycles and muscle activity before and after orthognathic surgery.

PURPOSE: The purpose of this investigation was to study the long-term effects of orthognathic surgery on mastication in patients before and after four surgical procedures: mandibular advancement, maxillary intrusion, maxillary intrusion with mandibular advancement, and maxillary inferior repositioning. MATERIALS AND METHODS: The components and timing of mandibular motion, electromyography (EMG), and estimated biting forces during mastication were studied in 61 patients who underwent orthognathic surgery for correction of four different deformities. The data were statistically compared with 38 control subjects using ANOVA. RESULTS: Preoperatively, there were no significant differences in the duration of the chewing cycles and mandibular excursions among the groups, nor did surgery have any affect on these variables. Before surgery, estimated occlusal forces in the patient groups were smaller than controls. Although these appeared to increase after surgery, the increases did not exceed changes in our untreated controls. CONCLUSIONS: The results of this study suggest that, with the exception of EMG and occlusal forces, mastication in orthognathic surgery patients is not significantly different from controls either before or after surgery. EMG during mastication, although significantly lower than in controls before surgery, showed significant increases after surgery, but these increases did not bring estimated occlusal forces up to control levels.

Adaptation, Physiological↗
PubMed1996

Bite forces before and after surgical correction of mandibular prognathism.

PURPOSE: The purpose of this investigation was 1) to compare morphologic parameters and voluntary bite forces between controls and a sample of patients with mandibular prognathism before surgical correction, and 2) to examine how these patients' bite forces adapt after treatment. PATIENTS AND METHODS: Twenty-four prognathic patients were compared with 24 controls before and up to 3 years after mandibular setback surgery. Measures of skeletal morphology and maximum isometric bite force were made on all subjects over time. Statistical analysis compared the controls, the patients before surgery, and the patients after surgery. RESULTS: Surgical shortening of the mandible averaged 4.1 mm, bringing most skeletal measures into the normal range. Before surgery, the jaw muscle mechanical advantages for patients were significantly smaller than for controls; surgery did not significantly change this relationship. Before surgery the patients had maximum isometric bite forces that were significantly less than those of controls. Bite forces steadily increased after surgery, approaching normal values within 2 to 3 years. CONCLUSIONS: The results of this study suggest that correction of mandibular prognathism by mandibular setback surgery produces some significant functional benefits.

Adolescent↗
PubMed1996

Functional and morphologic changes after combined maxillary intrusion and mandibular advancement surgery.

PURPOSE: The purposes of this investigation were 1) to compare the morphology and function of patients with combined vertical maxillary excess (VME) and mandibular retrognathia with that of controls, and 2) to examine how these parameters change after combined maxillary intrusion and mandibular advancement surgery. PATIENTS AND METHODS: Fifteen female VME/retrognathic patients were compared with 26 female controls before and for up to 3 years after orthognathic surgery. Facial skeletal morphology, mandibular range of motion, maximum isometric bite force, and levels of electromyographic activity (EMG) in selected muscles of mastication were measured on all subjects. Where appropriate, one-way analysis of variance (ANOVA) or t-tests were used to compare the patients with controls. Univariate repeated-measures ANOVA was used to study longitudinal changes. RESULTS: Preoperatively, patients' morphologic measurements were characteristic of VME compounded by mandibular retrognathia. At surgery, the maxilla was elevated an average of 2.8 mm, and the mandible was lengthened by an average of 7.1 mm. All of the postoperative morphologic measurements were closer to normal values. The patients' masseter mechanical advantage was significantly lower than that of controls both before and after surgery. Surgically induced changes in mechanical advantage were very small. The patients' maximum range of motion and excursion during mastication were all lower than those of controls before surgery. All measurements of mobility decreased immediately after surgery, with a gradual return to preoperative values. However, even 3 years after surgery, all of the motion measurements remained smaller than those of the controls. Before surgery, the patients had maximum isometric bite forces significantly lower than those of controls. Bite forces increased significantly after surgery, approaching normal values within 2 years. The activity levels in the muscles of mastication during isometric bites were not significantly altered by surgery. CONCLUSIONS: This study confirms that VME/retrognathia patients suffer from substantial deficiencies in their oromotor function. Surgical correction of this particular type of dentofacial deformity improves both the morphologic and functional deficits. Although some changes were not statistically significant, all were toward normalization of the presurgical values.

Adolescent↗
PubMed1996

Mandibular excursions and maximum bite forces in patients with temporomandibular joint disorders.

PURPOSE: This study evaluated mandibular motion and bite force in patients with temporomandibular joint disorders after joint surgery. PATIENTS AND METHODS: Maximum voluntary mandibular motion, maximum excursion during mastication, and maximum bite force were examined in 25 female patients before temporomandibular joint surgery. Their pretreatment performance was compared with that at 6 weeks, 6 months, and 1 year after surgery, and with performance of 26 normal female volunteers. RESULTS: Before surgery, all of the patients' movements and bite forces were smaller than those of controls. One year after surgery, maximum interincisal opening increased significantly, but lateral excursion and protrusion remained unchanged. Maximum bite forces increased significantly and nearly reached control levels. CONCLUSIONS: Patients with severe restriction in temporomandibular joint function exhibit general improvements in some mandibular movements and in maximum bite force after surgical treatment.

Adolescent↗
PubMed1996

Functional characteristics of patients with anterior open bite before and after surgical correction.

The purposes of this investigation were to compare functional performance between controls and a sample of patients with skeletal anterior open bite prior to surgical correction and to examine how the patients' oral motor function adapted after treatment. Five female patients with skeletal open bite malocclusion were treated with Le Fort I osteotomy and compared to sex-, size-, and age-matched controls. Measurements of skeletal morphology, mandibular range of motion, occlusal force, and muscle efficiency were taken on all subjects over time. Prior to surgery, all patients had lower occlusal forces than did controls at all bite positions. After surgery, occlusal forces at several occlusal positions increased significantly from the presurgical recordings but remained below the level of controls. The mechanical advantages of the muscles of mastication were not significantly different between controls and patients either before or after surgery. The results of this study suggest that correction of skeletal open bite malocclusion may improve occlusal force, but a larger sample is needed to confirm this finding.

Analysis of Variance↗
PubMed1995

The effects of orthodontic treatment on isometric bite forces and mandibular motion in patients before orthognathic surgery.

PURPOSE: Little is known about the effects of orthodontic treatment on oral motor function. The objective of this report is to evaluate changes in mandibular motion and maximum bite force that occur between the initiation of presurgical orthodontics and its completion before surgery. PATIENTS AND METHODS: Fifteen patients (9 women, 6 men) with a variety of dentofacial deformities were examined before and after presurgical orthodontics. Mechanical advantage of the muscles and bite points, mandibular range of motion, maximum isometric bite force, and levels of electromyographic (EMG) activity in the anterior and posterior temporalis and masseter muscles during isometric bites were recorded on all subjects over time. Data obtained before and after completion of presurgical orthodontics were statistically compared. RESULTS: Presurgical orthodontics reduced mandibular mobility somewhat, but the amount was not significant. Statistically significant reductions in bite force were noted after orthodontics for incisor, canine, premolar, and molar bite positions. No significant difference in the EMG/bite force slopes was obtained, nor was there any difference in the moment arms of the bite points or the muscles of mastication from orthodontics. CONCLUSIONS: This study showed significant changes in measures of oral motor function resulting from orthodontic treatment. A larger study is needed to confirm that these results will be similar in all orthodontic patients. There is no indication that these changes are the result of physiologic alterations of the muscles of mastication. The best current explanation is that these changes result from the pain and discomfort of the orthodontic appliances and the induced malocclusion.

Adolescent↗