Albert G Forgione’s research while affiliated with Hokkaido University and other places

The purpose of this study was to quantitatively evaluate the effects of experimental leg length discrepancies on body posture and dental occlusion. Thirty asymptomatic subjects (15 males and 15 females, ages 19-33, mean age 25.6 years) were included in this study and randomly assigned to one of two groups based on a table of random numbers. The only difference between group A and group B was the sequence of testing. Experimental leg length discrepancies were provided by using ten types of insoles with heights ranging from one to ten mm at one mm intervals, placed under both feet. The MatScan (Nitta Corp., Osaka, Japan) system was used to measure changes in body posture (center of foot pressure: COP) while subjects maintained the following three postural positions: 1. natural standing posture (control); 2. control with a heel lift under the right foot; or 3. control with a heel lift under the left foot. The T-Scan II system (Nitta Corp., Osaka, Japan) was used to analyze the results of changes in dental occlusion (center of occlusal force: COF) in the above-mentioned three postural positions. When subjects used a heel lift of six mm or more under the right foot, lateral weight distribution (LWD) shifted to the right side compared to the control (p<0.05). When a heel lift of four mm or more was used under the left foot, LWD shifted to the left side compared to the control (p<0.05). When subjects used a heel lift of eight mm or more under the right foot, occlusal force shifted to the right side compared to the control (p<0.05). When subjects used a heel lift of seven mm or more under the left foot, occlusal force shifted to the left side compared to the control (p<0.05). Based on these findings, it was concluded that leg length discrepancy affected body posture and dental occlusion.

Objectives: The purpose of this study was to evaluate the effect of changing body posture on body sway, head position, head and neck muscle activities and dental occlusion. Methods: Fifteen asymptomatic subjects (7 males and 8 females) volunteered for this study. The MatScan system was used to measure changes in body posture (center of foot pressure) while subjects maintained the following 2 postural positions: 1) natural standing posture (control), and 2) natural standing posture with both heels lifted. The T-scan III system was used to analyze occlusal force distribution in the 2 postures. Surface electromyographic (EMG) recordings were obtained for the masseter (MS), temporalis (TM), sternocleidmastoid (SCM) and trapezius (TR) muscles bilaterally in the 2 postures. A three-dimensional motion analysis system was used to measure changes in head position in the 2 postures. Changes in body posture and head position were measured simultaneously. Occlusal force distribution and EMG activities of all muscles were also measured simultaneously. The Wilcoxon test and Kendall's rank correlation test were used for statistical analysis. Results: When subjects lifted their heels, weight distribution and head position shifted significantly backward compared to the control (p<0.05) and showed a significant correlation (p<0.05). EMG activities of MS, TM and SCM with both heels lifted showed a tendency to increase compared to the control, and the increase rate of EMG activity for MS was larger than for TM. Occlusal force distribution in both initial tooth contact and centric occlusion with heels lifted shifted significantly forward compared to the control (p<0.05). Conclusion: It was concluded that changes in body posture affected the balance of weight distribution, head position and the balance of occlusal forces, and that there was a significant correlation between changes in body posture and head position.

The purpose of this study was to evaluate the effect of changing mandibular position on body posture and reciprocally, body posture on mandibular position. Forty-five (45) asymptomatic subjects (24 males and 21 females, ages 21-53 years, mean age 30.7 years) were included in this study and randomly assigned to one of two groups, based on the table of random numbers. The only difference between group I and group II was the sequence of the testing. The MatScan (Tekscan, Inc., South Boston, MA) system was used to measure the result of changes in body posture (center of foot pressure: COP) while subjects maintained the following 5 mandibular positions: (1) rest position, (2) centric occlusion, (3) clinically midlined jaw position with the labial frena aligned, (4) a placebo wax appliance, worn around the labial surfaces of the teeth and (5) right eccentric mandibular position. The T-Scan II (Tekscan, Inc., South Boston, MA) system was used to analyze occlusal force distribution in two postural positions, with and without a heel lift under the right foot. Total trajectory length of COP in centric occlusion was shorter than in the rest position (p < 0.05). COP area in right eccentric mandibular position was larger than in centric occlusion (p < 0.05). When subjects used a heel lift under the right foot, occlusal forces shifted to the right side compared to no heel lift (p < 0.01). Based on these findings, it was concluded that changing mandibular position affected body posture. Conversely, changing body posture affected mandibular position.

This study investigated the immediate effect of changing mandibular position on the electromyographic (EMG) activity of the masseter (MS), temporalis (TM), sternocleidomastoid (SCM) and trapezius (TR) muscles. Thirty-three (33) asymptomatic subjects (16 males and 17 females), ages 23 to 52 were selected. Surface EMG recordings were obtained for all muscles bilaterally with the mandible in a relaxed open position (relaxed) and during maximal voluntary clenching (fullbite) for the following: a non-repositioning appliance (NONREPOS) and repositioning appliance (REPOS). REPOS significantly reduced EMG activity of all muscles bilaterally during fullbite. During relaxation, reduction in EMG activity was only found for TR bilaterally. NONREPOS decreased the EMG activity bilaterally for TM and TR and unilaterally (left) for MS and SCM during fullbite. During relaxation, NONREPOS decreased muscle activity bilaterally for TR and SCM. A unilateral reduction was found for TM (right). These findings suggest that immediate alterations in mandibular position affect the cranio-cervical system. Both mandibular positions tested lowered the EMG activity of masticatory and cervical muscles in the relaxed and fullbite positions. The trapezius muscle was the most responsive to alterations in mandibular position.

The effect of vertical dimension of occlusion (VDO) on maximizing isometric deltoid strength (IDS) was measured in subjects with deep overbite. Sixteen female dental students with deep dental overbite and no history of temporomandibular joint disorder (TMD) were used as their own control and tested for isometric strength of the deltoid muscles, using a hand held strain gauge. Measurements were taken under four mandibular conditions: 1. habitual occlusion; 2. mandibular rest position; 3. biting on a bite elevating appliance set to the functional criterion of peak IDS; and 4. biting on a placebo appliance. Results showed that in deep bite subjects, isometric deltoid strength in habitual occlusion was significantly less than in the mandibular rest position. Isometric deltoid strength with the bite elevating appliance was significantly greater than isometric deltoid strength in habitual occlusion, as well as in the mandibular rest position. Isometric deltoid strength achieved in habitual occlusion and placebo did not differ. Results of this study support previous findings indicating that a change in the VDO will affect isometric strength of the upper extremities.

This randomized, double-blind study was designed to evaluate the effectiveness of the topical cream Theraflex-TMJ (NaBob/Rx, San Mateo, CA) in patients with masseter muscle pain and temporomandibular joint (TMJ) pain. Fifty-two subjects (5 males and 47 females) were instructed to apply a cream over the afflicted masseter muscle(s) or over the jaw joint(s) twice daily for two weeks. Theraflex-TMJ cream was used by the experimental group, while a placebo cream was used by the control group. The means of pain ratings were calculated prior to the application of the cream (baseline), after ten days of tx (period 1), and 15 days of tx (period 2) days of treatment and five days after stopping the treatment (follow-up). There was a significant decrease in reported pain levels from baseline in the experimental group for period 1 (p < 0.01), period 2 (p < 0.001), and follow-up (p < 0.01). For the control group, no significant differences were found between the different time periods (p > 0.05). There was evidence of minor side effects such as skin irritation and/or burning on the site of the application in two subjects in the experimental as well as two subjects in the control groups. The data strongly suggest that Theraflex-TMJ topical cream is safe and effective for reducing pain in the masseter muscle and the temporomandibular joint.

This randomized double-blind study evaluated the effectiveness of pulsed radio frequency energy therapy (PRFE) in patients with temporomandibular joint arthralgia. Forty subjects (age range 22 to 55 yrs.) were assigned randomly into two equal groups: (1) Experimental group received PRFE using the Energex unit (Energex, Inc. Emerson, New Jersey) and (2) Control group received PRFE placebo treatment using a sham device. Both groups received six applications to the TMJ area over two weeks. Data were analyzed for the following times: baseline, first and second follow-up visits. Numerical Rating Scale scores for TMJ pain showed a significant reduction over time for the experimental group (mean = 6.13 to 3.05, p < 0.001). There was also a significant effect for the controls (mean = 5.35 to 4.20, p = 0.01). The effect for experimental subjects was a mean reduction of 3.07 versus 1.15 for controls. The significant reduction in controls was attributed to the placebo effect. The experimental group showed a significant increase in mouth opening (mean = 34.95 to 41.70 mm, p = 0.002), right lateral movement (mean = 7.85 to 10.80 mm, p = 0.001) and left lateral movement (mean = 7.65 to 10.85 mm, p < 0.0001). No significant (p > 0.1) change in the control group occurred for mouth opening (mean = 38.50 to 39.65 mm), right lateral movement (mean = 8.60 to 8.75 mm) and left lateral movement (mean = 8.50 to 8.80 mm). No side effects were reported during the treatment and the two week follow-up. These results suggest strongly that PRFE is a safe and effective treatment for TMJ arthralgia as well as for increasing mandibular range of motion.

This study assessed the maxillomandibular relationship in temporomandibular disorders (TMD) patients, before and after short-term, flat plane bite plate therapy. It was of interest to determine the incidence and degree of mandibular deviation in a group of TMD patients and whether the mandible would shift to the midline and consequently affect reported symptoms. Seventeen female and three male subjects (age range 19-60) were included in the study. Thirteen subjects were diagnosed with myofascial pain while seven were diagnosed as exhibiting disk displacement with reduction (Research Diagnostic Criteria). After taking impressions for these subjects, casts were fabricated and mounted. Maxillomandibular relationship was evaluated by the Denar Centric Check system (Anaheim, CA). The maxillary and mandibular labial frena were used as a reference to evaluate mandibular shift. Symptom questionnaires were used to assess temporomandibular joint pain and clicking. All subjects exhibited deviation (12 subjects to the right and 8 subjects to the left) prior to bite plate therapy. After flat plane bite plate therapy, the mandibular position of all subjects shifted toward the labial frenum midline position. Based on the Binomial test, the shift was significant (p < 0.001). Measurements on the Centric Check system showed a significant movement of both condyles in the anterio-posterior plane as well as the vertical plane. There was also significant reduction in TMJ pain and clicking (p < 0.01). The results support the hypothesis that the balanced position of the mandible is with frena aligned. When occlusal obstructions are eliminated, the mandible will drift to this position.