Treatment of condylar hyperplasia of the mandible using unilateral ramus osteotomies

PURPOSE: The long-term outcome of bilateral and unilateral ramus osteotomies used for the treatment of unilateral condylar hyperplasia of the mandible are evaluated and compared. MATERIALS AND METHODS: Thirteen cases of unilateral condylar hyperplasia of the mandible were surgically treated during a 10-year period from 1985 to 1995. Seven of the patients were treated by bilateral ramus osteotomies alone; six were treated by unilateral ramus osteotomies of the affected side. Unilateral ramus osteotomy was combined with a maxillary Le Fort I procedure in two of the six cases. Preoperative analysis of patients, indications for case selection, and postoperative results relating to facial symmetry, temporomandibular joint (TMJ) pain, occlusion, and stability were compared in the two groups. RESULTS: The postoperative findings and long-term results in both groups of patients were favorable. Symmetry, arch coordination, and occlusion remained stable. TMJ pain and dysfunction were invariably cured postoperatively. Unilateral ramus osteotomies alone, or in combination with maxillary surgery when deemed feasible and applicable by preoperative clinical analysis, was sufficient to restore symmetry and occlusion in dentally compensated cases. CONCLUSIONS: This study shows that patients with unilateral condylar hyperplasia of the mandible and deviation can be treated favorably by unilateral ramus osteotomy of the affected side; bilateral ramus osteotomy did not have any advantage in such cases. In addition, this procedure, combined with a Le Fort I osteotomy of the maxilla, was also effective in restoring occlusal canting and facial symmetry in dentally compensated cases. However, bilateral ramus osteotomy was required in prognathic cases and in cases in which a unilateral procedure would cause excessive rotation of the contralateral condyle.     

Surgical treatment of ankyloses of the temporomandibular joint in children

Ankylosis of the temporomandibular joint leads in children to serious disorders such as loss of dentition, growth retardation of the lower jaw, facial asymmetry etc. During the period from 1993 till 1997 we treated 12 children incl. eight who had unilateral and four bilateral ankylosis. In six patients, after elimination of the ankylosis, reconstruction of the head was made with a total of nine costochondral grafts. In entire all patients the temporal muscle or a silicone plate was interposed between the skull base and mandible. Postoperative complications were minimal. Surgical treatment, which is only half of the issue of treatment, must be followed by long-term careful rehabilitation. The results which were achieved contributed in a significant way to a more favourable further development of the children.     

Costochondral grafts to replace mandibular condyles in juvenile chronic arthritis patients: long-term effects on facial growth

Long-term facial growth and clinical outcome after replacement of arthritic mandibular condyles by costochondral grafts and postoperative orthodontic guidance of the occlusion were studied until completion of facial growth in patients (n = 12) with juvenile chronic arthritis (JCA) affecting their temporo-mandibular joints (TMJs). The patients were between 10.1 and 16.7 years of age at surgery. Clinical records and radiographs for cephalometric measurements were taken preoperatively, 6-8 weeks after surgery and after completion of facial growth. A considerable potential for growth of the costochondral graft/mandible unit was demonstrated in all patients. The results also indicated a considerable risk of asymmetrical mandibular overgrowth (n = 8), which could not be correctly assessed until after skeletal maturation was complete. Without any active orthodontic treatment, compensatory growth of the alveolar processes closed the lateral open bites, which were created during surgery. The functional results of the reconstructed temporo-mandibular joints were good and the morbidity rate was low. Costochondral grafting is a versatile treatment when the TMJs are severely affected by JCA, but requires supervision of patients until skeletal maturation, to monitor possible mandibular overgrowth. Advantages of this method were re-established mandibular growth, good mandibular function, a low morbidity rate and early aesthetic improvement.     

Mandibular condyle hyperplasia. Therapeutic review

Excessive cartilage growth on the condyle process of the mandible can result from primary hyperreactivity of the growth cartilage or be a secondary adaptation to an imbalance in occlusive and/or cervicofacial conditions. Treatment depends on the distinction between these two forms. Primary active overgrowth is treated by condylectomy sparing the distal apparatus although conservative surgery to re-centering the temporomandibular joint and re-establish symmetry without condylectomy may be used in quiescent moderately active forms saving the joint. For secondary forms, the joint is re-centering and symmetry is re-established without condylectomy. If started early enough, orthopaedic treatment can avoid the development of secondary forms resulting an imbalance in occlusive and/or cervicofacial conditions.     

Treatment response to maxillary expansion and protraction

A prospective clinical trial was conducted to determine the skeletal and dental contributions to the correction of overjet and overbite in Class III patients. Thirty patients (12 males and 18 females with a mean age of 8.4 +/- 1.7 years) were treated consecutively with protraction headgear and fixed maxillary expansion appliances. For each patient, a lateral cephalogram was taken 6 months before treatment (T0); immediately before treatment (T1); and 6 months after treatment (T2). The time period (T1-T0) represented changes due to 6 months of growth without treatment; (T2-T1) represented 6 months of growth and treatment. Each patient served as his/her own control. Cephalometric analysis described by Bj?rk (1947) and Pancherz (1982a,b) was used. Sagittal and vertical measurements were made along the occlusal plane (OLs) and the occlusal plane perpendicular (OLp), and superimposed on the mid-sagittal cranial structure. The results revealed the following: with 6 months of treatment, all subjects were treated to Class I or overcorrected to Class I or Class II dental arch relationships. Overjet and sagittal molar relationships improved by an average of 6.2 and 4.5 mm, respectively. This was a result of 1.8 mm of forward maxillary growth, a 2.5-mm of backward movement of the mandible, a 1.7-mm of labial movement of maxillary incisors, a 0.2-mm of lingual movement of mandibular incisors, and a 0.2-mm of greater mesial movement of maxillary than mandibular molars. The mean overbite reduction was 2.6 mm. Maxillary and mandibular molars were erupted occlusally by 0.9 and 1.4 mm, respectively. The mandibular plane angle was increased by 1.5 degrees and the lower facial height by 2.9 mm. Individual variations in response to maxillary protraction was large for most of the parameters tested. Significant differences in treatment changes between male and female subjects were found only in the vertical eruption of mandibular incisors and maxillary and mandibular molars. These results demonstrate that significant overjet and overbite corrections can be obtained with 6 months of maxillary protraction in combination with a fixed expansion appliance.     

Management of posttraumatic malocclusion caused by condylar process fractures

PURPOSE: The aim of the study was to evaluate the results of orthognathic surgery in cases with posttraumatic malocclusion as a long-term complication of condylar process fractures. PATIENTS AND METHODS: A retrospective study on 21 patients with posttraumatic malocclusions attributable to condylar process fractures was performed. In group I, 15 patients were treated for asymmetric malocclusion with unilateral or bilateral mandibular ramus osteotomies. In group II, six patients were treated for anterior open bit with either a Le Fort I osteotomy (n=5) or a bilateral ramus osteotomy (n=1). All patients had clinical and radiographic follow-up for at least 1 year. RESULTS: Stable dental and cephalometric results were obtained in all patients except the one in group II who was treated with bilateral sagittal split osteotomies. In two cases, both in the asymmetric group, minor occlusal interferences had to be treated by equilibration in the early postoperative period. CONCLUSIONS: Orthognathic surgery is a predictable and stable method for the treatment of posttraumatic malocclusion due to condylar process fractures. Maxillary orthognathic surgery is successful in correcting symmetric anterior open bites due to bilateral condylar process fractures. Because posttraumatic malocclusion is a rare complication after closed treatment of condylar process fractures, and it can be treated satisfactorily using orthognathic surgery, routine open reduction and fixation of condylar process fractures is not indicated to prevent posttraumatic malocclusion.     

Studies on the hypotensive and bradycardic effects of 1-piperidinylmethyl-2-naphthol hydrochloride

An understanding of growth and development and the effect our appliances have on a person's growth and development is necessary in the selection of the therapeutic appliances we choose to use, out of the multitude available. Timing of treatment is also important in effecting positive changes in skeletal and dental relationships. Early treatment to correct skeletal discrepancies and gain arch length can allow for an increase in nonextraction therapy. Cervical extraoral appliances, maxillary fixed expansion appliances, and mandibular labial "E" arches can be used early to effectively reduce of skeletal discrepancies and to gain arch length without the fear of rotating the mandible down and back, permanently increasing the mandibular plane angle. Case reports are presented to illustrate the beneficial changes that can occur with early treatment with these appliances.     

Mandibular forces during simulated tooth clenching

Differential, functional loading of the mandibular condyles has been suggested by several human morphologic studies and by animal strain experiments. To describe articular loading and the simultaneous forces on the dental arch, static bites on a three-dimensional finite element model of the human mandible were simulated. Five clenching tasks were modeled: in the intercuspal position; during left lateral group effort; during left lateral group effort with balancing contact; during incisal clenching; and during right molar clenching. The model's predictions confirmed that the human mandibular condyles are load-bearing, with greater force magnitudes being transmitted bilaterally during intercuspal and incisal clenching, as well as through the balancing-side articulation during unilateral biting. Differential condylar loading depended on the clenching task. Whereas higher forces were found on the lateral and lateroposterior regions of the condyles during intercuspal clenching, the model predicted higher loads on the medial condylar regions during incisal clenching. The inclusion of a balancing-side occlusal contact seemed to decrease the forces on the balancing-side condyle. Whereas the predicted occlusal reaction forces confirmed the lever action of the mandible, the simulated force gradients along the tooth row suggest a complex bending behavior of the jaw.     

Midfacial growth after costochondral graft construction of the mandibular ramus in hemifacial microsomia

PURPOSE: The purpose of this study was to document vertical midfacial growth after costochondral graft mandibular ramus construction in children with type IIB and type III hemifacial microsomia (HFM). METHODS: This is a retrospective study of 33 children who underwent costochondral graft (CCG) construction for mandibular type IIB (abnormal, small, and medially displaced ramus, n = 19) and mandibular type III (absent ramus and glenoid fossa, n = 14) HFM, between 1980 and 1990. Types I and IIA patients were not included because their milder mandibular deformities were lengthened by osteotomy. Mean age at operation was 6.2 (2 to 10) years, and the mean follow-up period was 5.5 (1 to 13.5) years. Occlusal cant, piriform angle, and intergonial angle were measured on the most current posteroanterior (PA) cephalogram. The ratio of unaffected to affected ramus length was determined on the most current panoramic radiograph. Patient outcomes were classified based on the occlusal cant at the latest follow-up: group 1, successful result with a symmetrical maxilla (occlusal cant of <5 degrees); group 2, acceptable result (occlusal cant > or =5 degrees but <8 degrees), and Group 3, failure (occlusal cant > or = 8 degrees). OMENS scores were calculated for each patient: each of the five major anatomic deformities of HFM (orbital, mandibular, auricular, neural, and soft tissue) were graded 0 to 3 and summed. The mean differences in age at operation and OMENS scores between groups were calculated (ANOVA). RESULTS: At the end of follow-up, patients defined as having a successful result (group 1) had a mean occlusal cant of 2 degrees, a mandibular length ratio of 1.0, and an intergonial angle of 2 degrees. However, the final piriform angle was 7 degrees, indicating less vertical midfacial growth than maxillary alveolar growth. These patients were older at the time of operation (mean age, 6.7 years), and their mean OMENS score (6.3) was significantly lower (P = .004) than in patients in group 2 (mean age at operation, 6.3 years; mean OMENS score, 6.8) and group 3 (mean age at operation, 5.8 years; mean OMENS score, 7.8). In group 2, the occlusal cant, mandibular length ratio, and intergonial and piriform angles did not improve. In group 3, the occlusal cant and piriform angle became worse during the follow-up period. CONCLUSIONS: The results of this study indicate that after construction of the ramus and condyle in type IIB and III HFM patients, vertical midface growth is secondary to a combination of midfacial and alveolar growth. Patients operated on at an older age were more likely to have a successful long-term result. Finally, the severity of the overall deformity, as reflected in a higher OMENS score, appeared to be an important factor in the response to early correction.     

Gene expression of trehalase during post-dormant development of the brine shrimp, Artemia: comparison of the two species

The purpose of this article is to summarize the short-term and long-term results of the authors' clinical prospective study on the treatment of Class III malocclusion using the protraction facemask. An attempt is made to answer questions pertaining to this treatment modality. Twenty patients with skeletal Class III malocclusion were treated consecutively with maxillary expansion and a protraction facemask. A positive overjet was obtained in all cases after 6 to 9 months of treatment. These changes were contributed to by a forward movement of the maxilla, backward and downward rotation of the mandible, proclination of the maxillary incisors, and retroclination of the mandibular incisors. The molar relationship was overcorrected to Class I or Class II dental arch relationship. The overbite was reduced with a significant increase in lower facial height. The treatment was found to be stable 2 years after removal of the appliances. At the end of the 4-year observation period, 15 of the 20 patients maintained a positive overjet or an end-to-end incisal relationship. Patients who reverted back to a negative overjet were found to have excess horizontal mandibular growth that was not compensated by proclination of the maxillary incisors. A review of the literature showed that maxillary expansion in conjunction with protraction produced greater forward movement of the maxilla. Maxillary protraction with a 30 degrees forward and downward force applied at the canine region produced an acceptable clinical response. The reciprocal force from maxillary protraction transmitted to the temporomandibular joint did not increase masticatory muscle pain or activity. Significant soft tissue profile change can be expected with maxillary protraction including straightening of the facial profile and better lip competence and posture. However, one should anticipate individual variations in treatment response and subsequent growth changes. Treatment with the protraction facemask is most effective in Class III patients with a retrusive maxilla and a hypodivergent growth pattern. Treatment initiated at the time of initial eruption of the upper central incisors helps to maintain the anterior occlusion after treatment.     

Mandibular fracture complications

This paper presents the authors' experiences with 111 treated mandibular fractures and 16 cases of complication. Pertinent data on the fresh fractures are given, but the major part of the study deals with cause, diagnosis, and treatment of the complications of mandibular fractures. These are divided into four categories-infection, nonunion, malunion, and temporomandibular joint ankylosis, although only infection and temporomandibular joint ankylosis are included here. Unique mandibular fracture complications are reviewed.     

Microbial oxidative metabolism of diclofenac: production of 4''-hydroxydiclofenac using Epiccocum nigrum IMI354292

OBJECTIVE: The purpose of this study was to examine both condylar displacement of the temporomandibular joint after sagittal split ramus osteotomy with rigid osteosynthesis and intraoral vertical ramus osteotomy without osteosynthesis in patients with mandibular prognathism by means of three-dimensional computed tomography. STUDY DESIGN: In this pilot study, five patients treated with sagittal split ramus osteotomy and 5 patients treated with intraoral vertical ramus osteotomy were evaluated. A technique to superimpose a postoperative three-dimensional computed tomography image on its corresponding preoperative image was designed. Postoperative condylar displacement, rotation, and tilting were measured in three-dimensional computed tomography images. RESULTS: Within 3 to 6 months after surgery, changes in the inclination of the condylar axes were distinctly seen, although changes in the position of the condyles within the joints were minimal. In particular, outward rotation of the condylar long axes after intraoral vertical ramus osteotomy was a frequent finding. CONCLUSIONS: The three-dimensional computed tomography superimposition technique was a practical method of evaluating postsurgical condylar displacement after mandibular osteotomy.     

Open reduction without fixation of dislocated condylar process fractures: long-term clinical and radiologic analysis

PURPOSE: This study evaluates the long-term results of open reduction without fixation for displaced fractures of the condylar process. PATIENTS AND METHODS: Clinical and radiologic examinations were performed on 27 patients with 29 operated joints an average of 6.7 years postoperatively. The postoperative result was evaluated on the basis of occlusal and joint function, as well as radiographic assessment of condylar changes. RESULTS: Clinically, satisfactory results were achieved. Radiologically, despite correct intraoperative alignment of the fractured segments, a slight medial deviation of the condylar process was found on the posteroanterior radiograph. However, in only two cases was a 20-degree deviation observed. On final follow-up, 48% of the cases had a normal condylar configuration radiologically, and in the remaining cases, normal function was established even though there were condylar changes. Fully exposed and devascularized condylar processes generally showed more severe changes than those in which partial vascularization was maintained. CONCLUSION: The surgical management described enables a satisfactory outcome to be achieved with dislocated condylar process fractures.     

Control of the vertical dimension in Class II correction using a cervical headgear and lower utility arch in growing patients. Part I

A retrospective cephalometric study was performed comparing three groups of 30 growing patients with Class II, Division 1 malocclusions. Group 1 was treated with a cervical headgear/lower utility arch combination (CHG/LUA), group 2 was treated with a cervical headgear alone (CHG), and the third group was untreated. The average treatment time was 1 year, 6 months. No other appliances were used during this period. Maxillary and mandibular dental and skeletal treatment responses were compared with an analysis of variance (ANOVA) and a Scheffe's test. In addition, a multiple stepwise regression was performed to determine whether pretreatment measures of facial pattern were accurate predictors of mandibular rotational response. Both treatment groups demonstrated significant reduction in maxillary protrusion. The CHG-only group showed significantly greater anterior descent of the palatal plane as compared with the untreated group. The maxillary molars showed significant distal movement in both treatment groups without any extrusion beyond that seen with normal growth. The maxillary incisor demonstrated significant retroclination in the CHG-only group. There was no statistical difference among the groups for variables commonly used for measuring mandibular rotation or protrusion. The change in vertical position of the lower molar was not significantly different among the groups. A CHG as used in this study produced maxillary orthopedic and orthodontic changes without upper molar extrusion beyond that seen with normal eruption and in the absence of an opening rotation of the mandible, even in subjects with dolicocephalic facial patterns. The LUA did not appear to influence lower molar eruption or mandibular rotational response. None of the commonly used predictors of facial pattern, such as the Y-axis, XY-axis, or MP angle, accurately predicted mandibular rotational response. Further study would be necessary to ascertain whether this was a result of their invalidation as predictors, or a result of the treatment strategy employed.     

The health of our children continues to improve--but... (a litany of change--Part III)

Interarch occlusal relationships are defined by temporomandibular joint (TMJ) position. Determination of the most physiologic joint position is a logical prerequisite for occlusal analysis. Existing classification systems for occlusion do not consider TMJ position or condition when relating the mandibular arch to the maxillary arch or the range of adaptive changes that can affect the position of the condyles or influence long-term occlusal stability. If the relationship between occlusion and TMJ position is as important as many clinicians believe, condylar position must be defined precisely as an essential control in any clinical study that purports to evaluate the relationship between occlusion and any masticatory system disorder to include temporomandibular disorders. This article presents a new classification system that defines the relationship between maximal intercuspation and the position and condition of the TMJs. The classification uses guidelines that are specific enough to be consistent and verifiably reproducible. A recently introduced term, "adapted centric posture," is used in this classification to distinguish deformed TMJs that have remodeled or adapted to a conformation that can comfortably accept maximal loading. This classification is necessary because deformed but adapted joints may within certain conditions function with the same degree of comfort as intact, properly aligned condyle disk assemblies in centric relation.     

Correlation between maximum bite force and facial morphology in children

The correlation between maximum bite force and facial morphology was studied in 54 boys, 8 to 16 years old, and 66 girls, 7 to 17 years old. Bite force was measured at the first molars with a miniature bite force recorder. Facial morphology was evaluated on profile cephalograms. In addition, the number of teeth in contact in the intercuspal position was recorded with occlusal foils. In the girls, maximum bite force was correlated with the inclination of the mandible, the size of the gonial angle, and the ratio between posterior and anterior face heights. The correlations implied a large bite force with a small mandibular inclination and gonial angle, a large posterior face height in relation to the anterior face height, and a small bite force with the opposite facial characteristics. These correlations were nonexistent or weaker in boys. In both sexes, bite force was correlated with the number of occlusal contacts. Elimination of the influence of age and occlusal contact in the group of girls by the use of partial correlations reduced the correlation between bite force and facial morphology. A significant correlation with the size of the gonial angle remained, however, and the correlation with mandibular inclination was close to significance. In addition to the correlations found with facial morphology, the study clearly demonstrated the need to take gender and occlusal contacts into consideration in future studies of masticatory muscle function and strength in relation to facial morphology.     

Variability and stability in cognitive abilities are largely genetic later in life

Radiographic cephalometry has been used for the assessment of the effects of mandibular rotation and of posterior growth displacement of the temporomandibular joint on the development of the face and on overjet in 43 patients with complete unilateral cleft lip and palate between the ages of 10 and 15 years. Rotation acted mainly on vertical facial measurements and on the position of the lower jaw. The degree of posterior displacement of the temporomandibular joint exerted an influence on the position of the mandible, on the difference between the functional length of the upper and lower jaw, and on the occlusion of incisors. The direction of growth of the mandible as a whole represented the result of a combination of changes produced by the rotation of the jaw and by the degree of posterior displacement of the temporomandibular joint. The most favourable conditions for development were a combination of the neutral type of rotation with a more pronounced posterior displacement of the temporomandibular joint.     

Tomographic stability of condyle fossa relationships in 40 treated temporomandibular disorder patients

STATEMENT OF PROBLEM: Condylar position and stability after treatment of 40 temporomandibular disorder patients was studied. PURPOSE: This study determined pretreatment position and posttreatment condylar stability. MATERIAL AND METHODS: Forty temporomandibular disorder patients with symptoms of muscles of mastication pain, temporomandibular joint sounds, attrition, interceptive occlusal contacts, and restricted range of motion were used. Axial corrected midcut sagittal tomograms were made of the 80 temporomandibular joints before treatment. Tracings from the tomograms were used to measure and analyze pretreatment position and posttreatment stability. RESULTS: Pretreatment condyle fossa position was not concentric in 26 of 80 patients (32.5%). Posttreatment condylar position showed no change and was statistically stable. CONCLUSION: In this study of 40 temporomandibular disorder patients, no statistical change in condylar position was detected. Variable condylar positions were found in the 80 pretreatment axial corrected midcut sagittal tomograms. All patients were asymptomatic after 1 year.     

Evoked potentials as predictors of outcome in neonatal intensive care unit survivors: review of the literature

The twin blocks technique was developed by Dr. William Clark of Scotland during the early 1980s. Twin Blocks are an uncomplicated system that incorporates the use of upper and lower bite blocks. These bite blocks reposition the mandible and redirect occlusal forces to achieve rapid correction of malocclusions. They are also comfortable and the patients wear them full-time--including eating time. Occlusal forces transmitted through the dentition provide a constant proprioceptive stimulus to influence the rate of growth and the trabecular structure of the supporting bone. This feature of Twin Blocks means easier and quicker treatment. The occlusal inclined plane is the fundamental functional mechanism of the natural dentition. Twin Blocks are bite blocks that effectively modify the occlusal inclined plane to induce favorably directed occlusal forces by causing a functional mandibular displacement. Upper and lower bite blocks interlock at a 45 degree angle and are designed for full-time wear to take advantage of all functional forces applied to the dentition including the forces of mastication. The patients who were treated with Modified Twin Blocks received the following benefits: 1) large overjets and deep overbites were corrected. 2) Class II molar relationships were changed into Class I, and 3) the profiles of the patients were improved by anterior displacement of mandible.     

A growth control approach to Class II, Division 1 cases during puberty involving the simultaneous application of maxillary growth restriction and mandibular forward induction

A simple method that used headgear and a functional appliance simultaneously was used for the correction of Class II, Division 1 cases with severe denture base discrepancy. The treatment restricted the forward growth of the maxilla and advanced the mandible. The functional appliance, referred to as the mandibular growth advancer (MGA), advances the mandible progressively with a splint, with the objective of remodeling the condyle and the glenoid fossa in the temporomandibular joint. Functional adaptation was achieved as the muscles that are attached to the mandible adjusted to new positions. In the two cases that illustrate this method, the ANB angle decreased and the Ar-B distance increased over a short period to four and six times the mean Japanese growth rate, respectively. After the correction of the denture-base discrepancy, a multibracket fixed appliance was used for dental alignment, and good skeletal, occlusal relationships and profiles were obtained. Treatment of severe denture-base discrepancy in this manner may reduce the skeletal abnormality, decrease the number of extraction cases, and shorten the subsequent multibracket treatment time. And it may reduce the iatrogenic side effects caused by prolonged mechanotherapy with a fixed appliance.