Mandibular Mobility Research Articles

The effects of antitumor irradiation on mandibular opening and mobility: A prospective study of 58 patients

Objective. The purpose of this study was to analyze the effects of head and neck radiation therapy on jaw opening and mobility. Study Design. Maximum jaw opening and mandibular mobility were measured before and after radiation treatment in 58 patients presenting for angle down wedge, homolateral wedge pair, and parallel pair head and neck radiation treatment. Results. As dose to the temporomandibular joint and pterygoid muscles increased, maximal jaw opening decreased linearly. Mandibular dysfunction appeared to increase as radiation dose to the pterygoid muscles increased. Similar effects were not observed with temporomandibular joint irradiation. Irradiation of the pterygoid muscles appeared critical in the development of trismus. Angle down wedge treatment irradiated the temporomandibular joint and pterygoid muscles with clinical effects similar to those seen in homolateral wedge pair and parallel pair patients. Doses as low as 1493 cGy resulted in functional impairment. Conclusions. Future investigations into radiotherapy delivery and appropriate postradiation trismus treatment may reduce head and neck radiation morbidity. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;88:365-73)

Clinical and radiological evaluation following surgical treatment of condylar neck fractures with lag screws

It was the purpose of this study to evaluate the outcome of lag screw osteosynthesis in severely displaced fractures or fracture dislocations of the mandibular condyle as well as intra- and postoperative complications of this technique. From 1980 to 1996 a total of 492 patients with condylar fractures were treated with lag screw osteosynthesis. Clinical and radiological follow-ups were carried out in 230 patients with severely displaced fractures or fracture dislocations of the mandibular condyle. The period between surgery and follow-up was between 6 months and 2 years. The majority of the clinical results were satisfactory presumably due to the anatomically exact reduction of the fragment (93.4%). Extreme anatomic variations of the mandible (5.8%) and incorrect application of the technique (8.8%) resulted in reduced functional stability of lag screw osteosynthesis. Insufficient fragment reduction and postoperative complications (such as wound infection) entailed restriction of mandibular mobility and arthrotic deformations were seen as persistent radiological irregularities of the mandible. It has been possible to avoid complications and to achieve favourable functional results in complicated fractures of the mandibular condyle by applying strict indications for lag screw osteosynthesis and by considering the individual anatomical peculiarities.

Mandibular motion after closed and open treatment of unilateral mandibular condylar process fractures

Purpose: This study compared mandibular and condylar mobility after open or closed treatment for fractures of the mandibular condylar process. Patients and Methods: One hundred thirty-six patients (111 male, 25 female), 74 treated by closed and 62 by open methods, were included in this study. They underwent testing of mandibular and condyle mobility at 6 weeks, 6 months, and 1, 2, and 3 years postsurgery. A jaw-tracking device was used to assess mandibular motion. Radiographs that were traced and digitized were used to assess condylar displacement and condylar mobility. Standard statistical methods were used to assess differences between groups. Results: Patients treated by open reduction had significantly greater initial displacement of their condylar processes than did the group treated closed. Immediately after treatment and uprighting of the condyles in the open treatment group, patients treated closed had significantly more displacement. At 6 weeks, patients treated closed had some measures of mandibular mobility that were significantly greater than those in patients treated by open reduction. However, after the 6-week period there were minimal differences in mandibular mobility between groups. At 6 weeks, patients treated by open reduction had significantly greater vertical mobility of the condyle than patients treated closed despite less mouth opening. After the 6-week period, patients treated by open reduction continued to have greater condylar mobility on the fractured side than did patients treated by closed methods. No measures of postsurgical displacement correlated with mobility measures in patients treated by open reduction. However, several measures of mandibular displacement correlated with measures of mobility in patients treated closed, indicating that the more displaced the condylar process, the more limited the mobility of the mandible. Conclusions: Based on this study, patients treated for fractures of the mandibular condylar process by open reduction had somewhat greater condylar mobility than patients treated closed, even though the former group had more severely displaced fractures before surgery. Therefore, open reduction may produce functional benefits to patients with severely displaced condylar process fractures.

The influence of the spring activator on the mobility of the lower jaw in traumatically injured patients.

For functional rehabilitation and improvement of mandibular mobility, 14 patients with dislocated collum or collum fracture dislocations were treated with a spring activator after surgical-conservative treatment. With an interincisal distance of < 12 mm, therapy was started with a loop spring. The average age of the patients was 26.6 years. Eight patients showed additional traumatic injuries, 2 patients were seriously polytraumatically injured. The clinical investigations referring to the maximum mouth opening and maximal interincisal distance resulted in a good to very good functional rehabilitation in all cases. The average maximal interincisal distance of 31.7 mm at the beginning of the spring activator therapy could be increased to 47.3 mm. The largest increase of the maximal interincisal distance was observed after 4 weeks of therapy. The type of reaction, however, differed interindividually. Three patients showed a spontaneous improvement of the interincisal distance within the first 2 to 3 weeks of removal of intermaxillary fixation, whereas 7 patients showed no improvement or only slightly improved values until insertion of the spring activator. An enlargement of the interincisal distance could be achieved in almost every patient within a relatively short period of time despite a drastically reduced mouth opening. Consequently, because of its mode of action in the form of a neuromuscular influence, the spring activator is especially suitable for the functional rehabilitation of patients with fractures of the condylar process.

Interleukin-1β in synovial fluid from the arthritic temporomandibular joint and its relation to pain, mobility, and anterior open bite

Purpose: The purpose of this study was to investigate whether interleukin-1β in synovial fluid or blood plasma is involved in the development of pain or hyperalgesia of the temporomandibular joint (TMJ), as well as reduced mandibular mobility and anterior open bite. Patients and Methods: Twenty-nine patients with TMJ arthritis and seven healthy subjects were studied. VAS measurement of TMJ tenderness on palpation of the TMJ (TDP), TMJ pressure pain threshold and tolerance level (PPTL), mandibular mobility, pain during joint movements, and degree of anterior open bite (AOB) were assessed. IL-1β levels were analyzed in TMJ synovial fluid (SF-IL-1β) and blood samples and correlated with the preceding factors. Results: SF-IL-1β showed significant positive correlations with VAS measurement of pain, TDP, and AOB and a negative correlation with PPTL. Conclusions: This study indicates that IL-1β in the synovial fluid is associated with pain and hyperalgesia in the TMJ region as well as an anterior open bite. Concerning the latter condition, IL-1β seems to be a warning signal of tissue destruction.

The influence of neuropeptides, serotonin, and interleukin 1beta on temporomandibular joint pain and inflammation.

This article describes the possible role of various peptides in producing pain and inflammation in the temporomandibular joint (TMJ). Current research findings on the spectrophotometric quantification of TMJ synovial fluid for neuropeptide Y (NPY), serotonin (5HT), and interleukin-1beta (IL-1beta) are presented. NPY was found in high levels in the synovial fluid of arthritic TMJs with resting pain, and serotonin (5-HT) was found in patients with pain perceived on mandibular movement. These pain-related mediators were also associated with restricted mandibular mobility. Interleukin-1beta (IL-1beta) was found to be strongly associated with hyperalgesia over the TMJ as well as resting pain. Anterior open bite as a clinical sign of joint destruction was found to be associated with high levels of NPY and IL-1beta in the synovial fluid. IL-1beta was also related to the radiographic signs of joint destruction. Interaction between the peripheral nervous system (sensory and sympathetic nerves) and the immune system is probably of importance for the modulation of pain and inflammation in the TMJ, but this subject has to be investigated further with experimental clinical studies.

Pain and synovial fluid concentration of serotonin in arthritic temporomandibular joints

The aim of this study was to investigate the relation between serotonin in the synovial fluid (SF-5-HT) and pain of arthritic temporomandibular joints (TMJ). The study comprised 1 male and 10 female patients (22 TM joints) with bilateral TMJ pain or tenderness and a mean age of 42 years. The patients were studied regarding pain from the TMJ at rest and during mandibular movements as well as regarding pressure pain thresholds and tolerance levels over the TMJ. TMJ samples, obtained by saline washing of the joint, and blood serum samples were taken for measurement of the 5-HT content. There was a positive correlation between SF-5-HT and pain in the TMJ upon movement. Maximum voluntary mouth opening ability was negatively correlated to SF-5-HT. In conclusion, the results of this study indicate that 5-HT in the TMJ synovial fluid is related to pain perceived upon movement of the joint and to decreased mandibular mobility.

Pain, tenderness, mandibular mobility, and anterior open bite in relation to radiographic erosions in temporomandibular joint disease

The relationship between radiographic changes and clinical signs and symptoms of the temporomandibular joint (TMJ) was investigated in 39 patients with joint diseases. Radiographic erosions were found in 33% of the TMJ joints, and overall frequency of radiographic changes including remodeling was 47%. Fifty-four per cent of the patients had an anterior open bite (AOB). The AOB showed statistically significant correlation to the extension of erosion of the TMJ. Pain expressed by means of a visual analog scale, tenderness to palpation of the TMJ, and pressure pain threshold showed no significant correlation to erosion, but mandibular mobility showed significant negative correlation to erosive changes. In conclusion, AOB is correlated with erosive radiographic changes in this patient group. However, the degree of local pain and tenderness showed no correlation to radiographic changes.

Linear and angular measurements of the mandible during maximal mouth opening

1. Wooten JW: Physiology of the temporomandibular joint. Oral Surg Oral Med Oral Patbol 21:543, 1966 2. Obwegeser HL, Farmand M, Al-Majali F, et al: Findings of mandibular movement and the position of the mandibular condyles during maximal mouth opening. Oral Surg Oral Med Oral Patbol 63:517, 1987 3. Sarnat BG, La&in DM: The Temporomandibular Joint (ed 3), Springfield, IL, Thomas, 1979, p 85 4. Madsen B: Normal variations in anatomy, condylar movements, and arthrosis frequency of the temporomandibular joint. Acta Radio1 Diagn 4:273, 1966 5. Or S, Ergen G: The assessment of temporomandibular subluxation by means of cephalometry. Am J Orthod 76:165, 1979 6. Thompson JR: A cephalometric study of the movement of the mandible. J Am Dent Assoc 28:750, 1941 7. Ingervall B: Variation of the range of movement of the mandible in relation to facial morphology in young adults. Stand J Dent Res 79:133, 1971 8. Landtwing K: Evaluation of the normal range of vertical mandibular opening in children and adolescents with special reference of age and stature. J Maxillofac Surg 6:157, 1978 9. Agerberg G: Maximal mandibular movement in children. Acta Odontol Stand 32: 147, 1974 10. Mezitis M, Rallis G, Zachariades N: The normal range of mouth opening. J Oral Maxillofac Surg 47:1028, 1989 11. Muto T, Kanazawa M: The relationship between maximal jaw opening and size of skeleton: A cephalometric study. J Oral Rehabil 23:22, 1996 12. Travel1 J: Temporomandibular joint pain referred from muscles of the head and neck. J Pro&et Dent 10:745, 1960 13. Agerberg G: On mandibular dysfunction and mobility. Ph.D. thesis, University of Umea, Sweden, 1974 14. Pullinger AG, Low SG, Tay D: Differences between sexes in maximum jaw opening when corrected to body size. J Oral Rehabil 14:291, 1987 15. Yamauchi K, Ito K, Suematsu H, et al: Sex difference of Japanese adult profile with normal occlusion on cephalometric roentgenograms. J Jpn Ortbod Sot 26:155, 1967 16. Ingervall B: Range of movement of mandible in children. Stand J Dent Res 78:311, 1970 17. Westling L, Helkimo E: Maximum jaw opening capacity in adolescents in relation to general joint mobility. J Oral Rehabil 19:485, 1992 18. Muto T, Kanazawa M: Positional change of the hyoid bone at maximal mouth opening. Oral Sur Oral Med Oral Path01 771451, 1994

労働災害による顎顔面損傷患者のそしゃく障害の評価に関する研究

This study was designed to investigate masticatory disturbances in patients with occupational maxillofacial injuries. During the 3 -year 3 -month period from April 1992 through June 1995, 51 patients were examined on the basis of (1) dental findings, (2) mandibular mobility, (3) electromyograms (EMG), (4) occlusal findings by Dental Prescale®, and (5) masticatory efficiency rate calculated from the results of a questionnaire that assessed the ability to chew 173 foods.The following results were obtained:1. Masticatory efficiency rate could be estimated on the basis of occlusal variables assessed with Dental Prescale®. The most important occlusal variable with this method was maximal force.2. At a value of 40% or more, masticatory efficiency rate was correlated with dental findings and mandibular mobility.3. In this same group of patients, masticatory efficiency rate was correlated with electromyographic findings (silent period rate, etc.).4. Variables of the occlusion evaluated with Dental Prescale® were positively correlated with masticatory efficiency rate.5. In patients with a masticatory efficiency rate of 40% or more, masticatory disturbances could be generally estimated from masticatory efficiency rate.6. Many patients with a masticatory efficiency rate of less than 40% had lack of consistency between objective and subjective findings. Masticatory disturbances could therefore not be evaluated correctly by analyzing items (1) to (5) in this group of patients.

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.

Alteration of temporomandibular joint symptoms after orthognathic surgery: Comparison with healthy volunteers

Purpose: The purpose was to investigate alterations in temporomandibular joint (TMJ) dysfunction after orthognathic surgery. Patients and Methods: TMJ symptoms of preoperative patients (n = 30) were compared with those of healthy volunteers (n = 30), and changes in the symptoms were evaluated at 3- and 6-month postoperative intervals. Results: There was no significant difference in the incidence of TMJ sounds, deviation of mouth opening, and tenderness of TMJ and masticatory muscles between patients and volunteers. Patients did not report TMJ symptoms significantly more often than the control subjects. At both 3 and 6 months after surgery, half or more of the patients showed no change in TMJ sounds, deviation of mouth opening, or tenderness of TMJ and masticatory muscles. At each evaluation, some patients exhibited improvement of TMJ symptoms or showed changes for the worse. Findings of TMJ sounds were observed to be associated with the postoperative reduction of mandibular mobility. Conclusion: These results suggest that alterations of TMJ symptoms after orthognathic surgery do not always result from the correction of malocclusion.

Correlations between the loss of acoustic TMJ symptoms and alterations in mandibular mobility after surgical mandibular advancement

A longitudinal clinical-axiographic study including 10 patients who had undergone surgical mandibular advancement to correct a dental and skeletal Class II anomaly, produced evidence of correlations between alterations of acoustic symptoms and of mandibular mobility. In 7 of 11 movements, where TMJ-sounds disappeared, post-operative mandibular mobility was reduced to such a degree that the point at which the acoustic symptom originated pre-operatively could no longer be attained. On the other hand, in all cases, where TMJ sounds remained uninfluenced by the surgical intervention, reductions in mobility occurred only beyond this point. Even the persistence of losses of TMJ sounds during the further post-operative follow-up period could, in the majority of cases (4 of 7) be well explained by the persistence of mobility restriction. Accordingly, in the future a differentiation between mobility- and non-mobility-dependent alterations of TMJ symptoms should be made.

Occlusal control of mandibular elevator muscles.

Occlusal stability and mandibular elevator muscle function was studied in 25 women (20-30 yr of age). They had 27-32 fully erupted teeth with few treated occlusal surfaces, and craniomandibular function including mandibular mobility was normal. The aim was to analyze the influence of natural patterns of occlusal contact on electromyographic activity, unaffected by pain and functional disorders. Occlusal stability was assessed in the intercuspal and in lateral contact positions as the number of teeth with physical contact and the number of opposing pairs of teeth in contact. Electromyographic activity was recorded by surface electrodes over anterior and posterior temporalis and masseter muscles. In general, positive correlations were found between occlusal stability in intercuspal position and moderate to strong static and dynamic contractions, most significant in masseter muscles, indicating that forceful contraction of these muscles implies stable occlusion. Systematically, the duration of activity during chewing was negatively correlated with occlusal stability in the intercuspal position, most pronounced in working-side muscles. This pointed to shorter contractions with stable occlusion and is interpreted as the result of less need for stabilizing activity. It is concluded, that the correlations between occlusal stability and elevator muscle function are probably based on feedback mechanisms from periodontal pressoreceptors.

Changes in mandibular mobility after different procedures of orthognathic surgery.

A prospective study including 63 adult Class II and Class III patients was carried out in order to examine short- and long-term effects of four different treatment methods on mandibular mobility. The patients were treated either (Group A, control-group) orthodontically alone or (Group B) by a LeFort I-osteotomy, a (Group C) mandibular advancement or (Group D) a two-jaw surgery/mandibular set-back. In the surgery-groups (B, C, and D) maximum opening, protrusion and lateral excursions were measured 2 days pre-operatively (T0), and 3, 8, 14.5, and 25.5 months post-operatively (T1-T4). In the control-group (A) at T0 and T4 was measured, only. Significantly differing effects of the four treatment methods on mandibular mobility were detected. (A) Orthodontic treatment alone, (B) maxillary advancement by LeFort I osteotomy, and (D) two-jaw surgery/mandibular set-back osteotomy did not influence mandibular mobility permanently. Temporary decreases in groups B and D (P less than or equal to 0.05) were observed, however. In contrast, permanent reductions after (C) mandibular advancement took place (P less than or equal to 0.001). Longitudinal survey showed that in all surgery groups recoveries were limited to a short period of 3-14.5 months, depending on the movement. Surprisingly, a closer similarity between the LeFort-I group (B) and the two-jaw surgery group (D), rather than between the sagittal-split groups (C and D), was seen indicating that the problem of reduced mobility after orthognathic surgery can be limited to Class II therapy. It was concluded that in Class III therapy, the application of rigid fixation in combination with a method of maintaining condyle-position, thereby dispensing with maxillomandibular fixation, prevents permanent reductions in mobility and guarantees a rapid recovery to pre-operative mobility levels.

A survey of craniomandibular disorders in 800 15-year-olds. A follow-up study of children with malocclusion.

Seven-hundred-and-ninety-one 15-year-olds were subjected to an anamnestic and clinical examination of craniomandibular disorders. These individuals had been examined at the age of 12 years and this is one section of an extensive longitudinal investigation into the effects of malocclusion, and the effectiveness of orthodontic treatment. The children were originally selected on the basis of presence of malocclusion. Signs of CMD were found in about half of the subjects. The proportion of individuals without any signs of CMD had decreased during the 4-year period. However, the number of subjects with severe signs remained very small. Changes in severity of CMD according to Helkimo's index of clinical dysfunction were mainly attributed to an increased prevalence of impaired TMJ function. An increase in prevalence of reported symptoms was found involving headache and joint sounds. The other recorded symptoms did not show any significant increase in prevalence. Mandibular mobility showed only minor changes from 12 to 15 years of age.

Craniomandibular dysfunction following surgical correction of mandibular prognathism.

Craniomandibular function was studied in 36 adult patients in whom mandibular prognathism was corrected with a combination of surgical (vertical ramus osteotomy) and orthodontic procedures. Each patient was examined up to 1 week before surgery and again 6 months later. Mandibular mobility, impaired function of the temporomandibular joint, and pain in the masticatory muscles and temporomandibular joint were evaluated. Data were classified according to a numerical scale and patients were divided into three groups: symptom free, mild symptoms and severe symptoms. Although there was no difference in the overall frequency of the three functional groups during the two phases of examination, 20 patients showed a change in functional status following surgery. Before surgery, decreased mandibular mobility was found in 19 patients; after surgery, four additional patients were included in this group. Temporomandibular joint function improved in 10 patients and three patients had less pain. The frequency of muscle pain did not change. Postoperative maximal interincisal opening was reduced by 5.4 mm (p less than 0.001) but lateral excursive movements did not change significantly. No significant relationships were found between pre- and postoperative mandibular mobility, temporomandibular joint function and muscle pain. Females experienced mild or severe dysfunction more often than males at both examinations, but the difference was not statistically significant.

Recovery of mandibular mobility following orthognathic surgery

The aim of this prospective study was to define the patterns of recovery of mandibular mobility following three commonly performed orthognathic surgical procedures. Twenty-two consecutive patients undergoing either isolated Le Fort I osteotomy (LE FORT; n = 7), sagittal split ramus osteotomies (SSRO; n = 7), or intraoral vertical ramus osteotomies (IVRO; n = 9) were studied. LE FORT and SSRO patients had no mandibular immobilization, whereas IVRO patients were immobilized by dental fixation for 3 weeks. Mandibular mobility was assessed by measurement of maximal mandibular opening (MMO) and lateral and protrusive excursions. No significant difference in MMO was observed between groups prior to surgery (LE FORT, 47.0 mm; SSRO, 50.7 mm; IVRO, 54.5 mm). A significant reduction in MMO occurred immediately after surgery in the LE FORT and SSRO groups and at release of fixation in the IVRO group. Each group returned to presurgical levels of mandibular mobility at a different rate following surgery. LE FORT patients recovered quickly, regaining 83% (mean, 38.7 mm) of MMO by 1 month and exceeded preoperative levels (mean, 49.6 mm) by 6 months. SSRO patients showed hypomobility (mean, 23.5 mm) after 1 month, with significant improvement in MMO (mean, 38.0 mm) at 2 months, and nearly complete recovery (96.2%; mean, 48.8 mm) at 6 months. IVRO patients recovered rapidly after release of dental fixation, achieving 78% (mean, 39.8 mm) of preoperative MMO at 2 months. This study shows that significant differences in recovery patterns of mandibular mobility exist between surgical procedures. The clinician should be aware of these differences in recovery patterns in defining goals for individual patient rehabilitation. Each patient can be expected to regain near-normal MMO in 3 (LE FORT) to 6 (SSRO, IVRO) months using the surgical and physiotherapy procedures described in this study.

Coronoid process elongation in rhesus monkeys ( Macaca mulatta) after experimentally induced mandibular hypomobility : A cephalometric and histologic study

The present study provided an experimental model that allowed a cephalometric and histologic analysis of craniofacial growth in monkeys with induced translatory impairment of the mandibular condyle. Cauterization was performed anterior to the joint in nine experimental rhesus monkeys, while eight animals as control subjects. The experimental procedure produced mandibular hypomobility in six animals, in three by means of temporomandibular joint ankylosis and in three by means of dense scar tissue formation anterior to the joint. In the remaining three experimental animals no restriction of mandibular mobility was created. Mandibular hypomobility was found to induce elongation of the coronoid process and was also associated with bone deposition in the gonial region. In contrast, normal remodeling of the gonial region was found in the experimental animals with normal range of movements and in the control animals.

How invasive is TMJ double-contrast arthrography in combination with cinematography? Patient discomfort versus known diagnostic gain

There is no doubt that double-contrast TMJ fluoroscopic tomography enables a differential diagnosis and treatment in internal derangement pathosis. Its indication is, a part from the expected diagnostic gain, also determined by the degree of its invasiveness, and other alternative diagnostics being available (nuclear magnetic resonance). Data on patient discomfort and complications were gathered in 63 arthrotomographies; pain sensations and mandibular mobility, during and after the procedure in particular, were studied. We consider, along with Westesson, 3 the procedure to be less invasive than commonly considered, once the surgeon-radiologist has gained enough experience.