Functional Appliances Research Articles

Efficacy of Arthroscopic Diskopexy on Condylar Growth in Temporomandibular Joint Anterior Disk Displacement: A Randomized Clinical Trial.

Adolescents with temporomandibular joint (TMJ) anterior disk displacement (ADD) frequently develop dentofacial deformities. It is unknown whether adjunctive arthroscopic diskopexy compared with orthodontic treatment alone increases condylar growth and then improves dentofacial deformity. This study aimed to determine whether arthroscopic diskopexy before functional appliance (joint-occlusal treatment) or single functional appliance (occlusal treatment) increases condylar growth and improves dentofacial deformity among adolescents with TMJ ADD. A multicenter, randomized, parallel, controlled trial was conducted in 3 centers in China. Adolescents diagnosed with TMJ ADD and dentofacial deformity were enrolled. Eligible participants were randomly assigned to a joint-occlusal group or occlusal group at a ratio of 2:1. Magnetic resonance imaging scans and cephalometric radiographs were evaluated at baseline, at 8 months, and at 14 months. The primary outcome was changes in condylar height from 14 months to baseline. Secondary outcomes were changes in skeletal position. A total of 240 patients (14.65 ± 1.88 years of age) were randomized (joint-occlusal group, 160; occlusal group, 80). The overall difference in condylar height between groups was 3.65 mm (95% CI, 3.10 to 4.19 mm; P < 0.001). The between-group differences in condylar height on the left and right sides were 3.60 mm (95% CI, 2.92 to 4.28 mm; P < 0.001) and 3.69 mm (95% CI, 3.06 to 4.32 mm; P < 0.001), respectively. Significant between-group differences were noted in skeletal position (all P < 0.001). Joint-occlusal treatment can promote condylar growth and improve dentofacial deformity in adolescents after 14 months when compared with single occlusal treatment. Therapeutic, I.

Elastodontic Therapy with Oral Bioactivator Devices: A Review

Scientific studies have shown that dysfunctional problems associated with dysmorphisms are the base of malocclusion. The position of the mouth and the head is a component of the general postural arrangement, so any head misalignment creates disharmonies and tensions among the neck muscles. Elastodontics is a treatment based on the use of removable elastomeric devices. These functional appliances are made of elastomeric material, acting tridimensionally on a neuromuscular system with orthopaedic and dental effects. Bioactivators have a vestibular and lingual flange with a free central area that permits them to position teeth without constraints. The flanges are linked by an occlusal plane that maintains the two skeletal bases and teeth in first-class normocclusion with propulsive and retropulsive effects on the maxilla and mandible. Elastomeric devices are generally well tolerated by patients requiring simple collaboration and management. This review aim is to describe the indications and limits of orthodontic therapy with elastomeric devices to provide an overview of elastodontics.

A Dual-Layer Orthogonal-Layout Thin-Film Force Sensor for Digital Orthodontic Functional Appliances

Measuring the force exerted on oral tissue is crucial for orthodontic treatment. Without proper tools and methods, orthodontists must rely on their clinical experience to estimate the force, which limits the efficiency and accuracy of diagnosis and treatment. Previous works using flexible force sensor arrays and wireless technology are power-hungry and require either complex wiring or batteries for power supply. However, human oral nerves are highly sensitive to foreign objects, so these solutions are not suitable for clinical practice. This work presents a thin-film force sensor based on carbon paste on a flexible printed circuit (FPC) substrate with an area of 24×4mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The sensor is embedded in functional appliances and can be read out through a miniature connector by a handheld device that uses frequency-domain signal processing. The device is powered by a 360-mAh battery and can last for 15 hours with a form factor of 86×40×21 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . The device achieves a force resolution of 10 mN with an update rate of 10 Hz. Six samples are characterized and after two-point calibration, this system achieves a force accuracy of 1.3/-0.6 N. Our measurement results also show that the sensor is robust against liquid environment. A dual-layer orthogonal-layout method is proposed to check the alignment of the contact surfaces.

The Correlation between Quantitative Cervical Vertebral Maturation and Mandibular Dimensions in Children Aged 8-16 Years: A Cross-Sectional Analytical Study

Background: During growth modification, the mandible plays a crucial role in functional orthopaedic treatment. To maximize the efficacy and efficiency of functional appliance therapy, one must know when to initiate treatment. To maximize the efficacy and efficiency of functional appliance therapy, one must know when to initiate treatment. To accurately determine when to initiate functional appliance therapy, the contemporary maturity indicators utilised are subjective with poor reproducibility and validity. Quantitative cervical vertebral maturity indicators are quantitative with good reproducibility. Objective: To determine the correlation between quantitative cervical vertebral maturation and mandibular dimensional changes in 8–18-year-old growing children. Material and Method: In this prospective cross-sectional analytical study, 164 samples were employed with an age range of 8–18 years. Samples were divided into four groups as per the quantitative cervical vertebral maturity indicator. Pubertal staging was analysed utilising the Li Chang, et al. method on a lateral cephalometric radiograph, and mandibular dimensions were measured as the total mandibular length of a condylon-gnathion line, the height of the mandibular ramus from the condylon-gonion intersection line, and the length of the mandibular body from the gonion intersection-gnathion line. Statistical Analysis: The data obtained was analyzed using Statistical Package for the Social Sciences (SPSS) software; descriptive statistics, student t test and bivariant analysis were applied. Results: The mean total mandibular length was seen at its maximum in periods of high acceleration velocity. Intergroup analysis shows significant differences between the groups, and there is a strong correlation between maturational stage and mandibular dimensional change. Conclusions: During functional orthopaedic treatment planning, the mandible can be utilised as a skeletal maturity indicator.

An assessment of masticatory efficiency and occlusal load distribution in adolescent patients undergoing orthodontic treatment with functional jaw orthopedics: A prospective cohort study

IntroductionFunctional jaw orthopaedics, produces a radical change in the occlusal scheme and the masticatory apparatus, particularly in patients with Class II malocclusion. It remains to be seen how the changes brought about by a functional appliance alter the masticatory ability of a growing child, who needs the necessary nutrition to properly grow the craniofacial region. Materials and methodsPretreatment and Post-treatment values of masticatory efficiency and the distribution of the occlusal load at centric occlusion were evaluated and compared for 20 patients with Class II division 1 malocclusion undergoing functional jaw orthopaedics. ResultsSignificant increase in the masticatory efficiency was seen during and after treatment (p < 0.5) There was an increase in the anterior distribution of occlusal load associated with a concomitant decrease in the posterior region at centric occlusion. ConclusionImprovement in the masticatory efficiency was observed after treatment of a retrognathic mandible with functional jaw orthopaedics in the adolescent participants with Class II malocclusion. This highlights the importance of treatment with functional jaw orthopaedics, which apart from providing esthetic and functional improvement also improves the ability of a growing child to extract proper nutrition from his/her diet.

Reflection on patients’ experience with orthodontic appliances wear and its impact on oral health related quality of life: observational comparative study

BackgroundThe objective of this study was to explore and compare patient’s experience with the use of a removable functional appliance or fixed orthodontic appliance and its influence on oral health-related quality of life.Material and methodsThis clinical trial included 81 participants having Class II Division 1 and age ranging between 10 and 16 years. The participants were included in any of a three equal groups according to the set inclusion and exclusion criteria; Group 1: patients treated with a Twin-Block functional appliance; Group 2: patients treated with a fixed orthodontic appliance only; and Group 3 (control group): patients not in orthodontic treatment yet. The COHIP SF-19 was used. Patients were given the questionnaire as follows: Group 1: (1) after at least 8 months from starting treatment; (2) after completing phase 1 by 2–3 months without wearing the appliance; Group 2: (1) just before debonding; (2) after finishing the treatment by 2–3 months without any appliances; and Group 3: (1) at the patient’s first visit to the orthodontic clinic; (2) after 2–3 months from the first visit to the orthodontic clinic and before starting any treatment.ResultsThe 81 participants were 31 males and 50 females with median age of 13 years. The total COHIP SF-19 scores at baseline were 57 (49–64), 67 (63–72), and 47 (42–53) for the Twin-Block, the fixed appliance, and the malocclusion groups, respectively. Two-month mean scores adjusted to the baseline scores were 64.82 ± 1.15, 65.65 ± 1.47, and 54.45 ± 1.44 for the Twin-Block, the fixed appliance, and the malocclusion groups, respectively.ConclusionsBoth at baseline and two-months (adjusted to the baseline scores), participants in the malocclusion group showed compromised socio-emotional quality of life and reported the poorest total OHRQoL. At the baseline, better socio-emotional and total OHRQoL was reported by the fixed appliance group compared to the Twin-Block group but, after two months both groups gave similar sores. Therefore; patients’ perceptions about their experience with the orthodontic appliance might change.

Assessment of Soft Tissue, Airway Dimension and Hyoid Bone Position in Class II Patients Treated by PowerScope Class 2 Corrector.

This study aims to assess the changes in the soft tissue, pharyngeal airway dimensions, and hyoid bone position in patients treated with PowerScope Class 2 corrector to correct the skeletal Class II pattern. This study was conducted on a sample of 20 cases diagnosed with Class II malocclusion. The lateral cephalograms were taken before (T1) and after functional appliance therapy (T2) and were traced. The outcomes were compared for the mean changes in soft tissue, airway way dimension, and hyoid bone position. The paired t-test was used for the data comparisons wherein p < 0.05 was kept for statistical significance. The mean values before and after treatment for H angle, mentolabial angle, lower lip E-line, upper lip S-line, lower lip S-line, and lip strain were 19.88 ± 2.77 vs 17.13 ± 1.659, 94.09 ± 12.164 vs 101.75 ± 11.28, -2.47 ± 1.213 vs -1.38 ± 0.976, 3.99 ± 0.19 vs 2.64 ± 0.32, 9.01 ± 0.247 vs 9.43 ± 0.238, 10.24 ± 0.510 vs 10.64 ± 0.52, respectively, which were statistically significant (p < 0.05). All airway spaces (except for lower pharyngeal space) and hyoid bone parameters were significantly improved posttreatment. The facial convexity, upper E-line, Z-angle, nasolabial angle, and lower pharyngeal space did not show statistically significant changes. The rest of the soft tissue parameters, oropharyngeal air spaces, and hyoid positioning measured in the study showed significant improvement after treatment with the PowerScope appliance in Class II patients. Class II malocclusion is the most common dental anomaly with a high degree of prevalence in the population. This study will help the clinician in understanding the improvement of soft tissue, airway dimension, and hyoid bone position changes on treatment with a fixed functional appliance for the correction of Class II cases, thereby ensuring the greater success of orthodontic therapy in the future.

The use of the Hanks Herbst vs Twin-block in Class II malocclusion: A randomized controlled trial

This 2-arm parallel study aimed to compare and evaluate the efficiency of Hanks Herbst (HH) and Twin-block (TB) functional appliances in treating adolescents with Class II malocclusion. A parallel-group randomized controlled trial was undertaken in a single United Kingdom hospital. Eighty participants were recruited and randomized in a 1:1 ratio to receive either the HH or TB appliance. Eligibility criteria included children aged 10-14 years with an overjet of ≥7 mm without dental anomalies. The primary outcome was the time (in months) required to reduce overjet to normal limits (<4 mm). Secondary outcomes included treatment failure rates, complications and their impact on oral health-related quality of life (OHRQOL). Randomization was accomplished using electronic software with allocation concealed using sequentially numbered, opaque, and sealed envelopes. Blinding was only applicable for outcome assessment. Data were analyzed using descriptive statistics and regression analyses to detect between-group differences, including Cox regression for time to treatment success. HH was significantly faster than TB in reducing the overjet to within normal limits (95% confidence interval [CI], -3.00 to -0.03; P= 0.046). Mean overjet reduction was more efficient with the HH than the TB appliance (ß= 1.3; 95% CI, 0.04-2.40; P= 0.04). Fifteen (37.5%) of the participants in the TB group and 7 (17.5%) in the HH group failed to complete the treatment (hazard ratio= 0.54; 95% CI, 0.32-0.91, P= 0.02). However, TB was associated with fewer routine (incidence rate ratio= 0.81; 95% CI, 0.7-0.9; P= 0.004) and emergency (incidence rate ratio= 0.1; 95% CI, 0.1-0.3; P= 0.001) visits. Chairside time was greater with the HH (ß= 2.7; 95% CI, 1.8-3.6, P= 0.001). Participants in both groups experienced complications with similar frequency. A greater deterioration in OHRQOL was found during treatment with the TB. Treatment with HH resulted in more efficient and predictable overjet reduction than TB. More treatment discontinuation and greater deterioration in OHRQOL were observed with the TB. However, HH was associated with more routine and emergency visits. ISRCTN11717011. The protocol was not published before trial commencement. No specific external or internal funding was provided. Treatment for participants was provided as part of routine orthodontic treatment in the hospital.

Indian Board of Orthodontics Case Report: Management of Skeletal Class II Division 1 Malocclusion With Single Phase Fixed Orthodontic Treatment Along With Forsus FRD Fixed Functional Appliance

Indian Board of Orthodontics Case Report: Management of Skeletal Class II Division 1 Malocclusion With Single Phase Fixed Orthodontic Treatment Along With Forsus FRD Fixed Functional Appliance

Treatment of a severe skeletal Class II malocclusion through growth modification: a problem-oriented case report

Abstract A skeletal Class II malocclusion is an anteroposterior discrepancy resulting from a combination of skeletal and dental factors. In adolescent patients, it is possible to leverage their growth potential to address bone deformities and minimise the need for future surgical interventions. In the present case report, a combination treatment approach was adopted which included a functional appliance, fixed appliances, and temporary anchorage support, to treat a 13-year-old Chinese male with a severe skeletal Class II malocclusion. After a treatment duration of 36 months, the patient achieved a favourable occlusion and an improved facial profile. Subsequently, a stable occlusal relationship and balanced facial proportions were maintained during a 2-year retention period.

Distal mandibular position treatment in adolescence: use of twin blocks

Class II malocclusion was described by Angle, a classification based on the discrepancy in the anteroposterior direction. From the therapeutic point of view, Class II malocclusion due to mandibular retrusion has been approached with different treatments. Twin blocks are functional appliances that reposition the mandible and redirect occlusal forces. A clinical case of a young Class II patient with mandibular distoposition using Twin Blocks is developed. It will be confirmed if the principles and objectives developed by Clark are evident in our patients.

Comparative study of changes in the airway dimensions following the treatment of Class II malocclusion patients with the twin-block and Seifi appliances.

Functional appliances are frequently used to stimulate mandibular growth in cases of Class II malocclusion with mandibular deficiency. Many studies have reported improved pharyngeal airway passage (PAP) dimensions following functional appliance therapy in children. The present study aimed to assess changes in the airway dimensions following the treatment of Class II malocclusion patients with the twin-block and Seifi appliances. Lateral cephalograms of 37 patients with Class II malocclusion and mandibular deficiency treated with the twin-block appliance (n = 20) or the Seifi appliance (n = 17) were assessed in this before-and-after study. The preoperative and postoperative lateral cephalograms were compared to determine changes in the airway dimensions at the level of the palatal plane (PP), the occlusal plane (OP) and the 2nd-4th cervical vertebrae (C2-C4) in the 2 groups. The results were analyzed with the t test and the one-way analysis of covariance (ANCOVA). After treatment, significant changes occurred in the point A-nasion-point B (ANB) and sellanasion-point B (SNB) skeletal cephalometric indices in the twin-block appliance group, and in ANB, SNB and incisor-mandibular plane angle (IMPA) in the Seifi appliance group. The airway dimensions at the level of PP, OP and the 3rd cervical vertebra (C3) significantly increased postoperatively as compared to the baseline in the twin-block appliance group (p < 0.05). The increases in the airway dimensions at the level of PP and C3 in the twin-block appliance group were significantly greater than in the Seifi appliance group (p < 0.05). The treatment of Class II Division I malocclusion with the twin-block appliance significantly increased the airway dimensions at the level of PP, OP and C3, whereas the Seifi appliance did not cause any significant changes in the airway dimensions.

Anterior crossbite treatment using functional orthopedic appliance: a case report

Anterior crossbite can affect primary, mixed, and permanent dentitions. Early treatment is recommended, as it can impact facial, aesthetic, functional, and developmental aspects. The etiology of anterior crossbite is multifactorial, including dental, skeletal, and postural origins. Treatment should be defined based on age and etiology, with various therapeutic resources available for correction. In primary dentition, direct flat tracks, different types of functional orthopedic appliances, quad-helix, and facial mask can be used. In mixed dentition, fixed segmented or continuous orthodontics, elastics, and other devices can be added to the treatment. In permanent dentition, orthognathic surgery may be indicated for adults, especially in cases of anterior crossbite associated with skeletal Class III that cannot be compensated dentally. This case report describes the treatment of early mixed dentition anterior crossbite with a functional orthopedic appliance at the Orthodontic Specialization, Postgraduate Course at Modal college, Belo Horizonte, Minas Gerais, Brazil. After correction, proper chewing functions were reestablished with ideal developmental stimuli.

Effects of fixed functional orthodontic treatment in hypodivergent and hyperdivergent class II patients—a retrospective cephalometric investigation

ObjectiveTo compare skeletal and dentoalveolar changes after orthodontic treatment of class II malocclusion in patients with hypodivergent and hyperdivergent growth patterns through cast splint fixed functional appliances (FFA).Materials and methodsN = 42 out of n = 47 patients with mandibular plane angles < 34° or ≥ 34° were divided into a hypodivergent (n = 24) and a hyperdivergent (n = 18) group. All patients received a single-step mandibular advancement protocol through an FFA. Lateral cephalograms were analyzed after initial leveling and alignment (T1) and immediately after FFA removal (T2). The therapeutic effect was calculated through comparison with age-matched controls from a growth survey. Statistical significance was set at p < 0.05.ResultsHypodivergent and hyperdivergent patients showed different treatment outcomes, but significant differences existed only for overbite and interincisal angle. Nearly all measurements suggested similar treatment-related changes for both groups with exception for dentoalveolar parameters.ConclusionTreatment with FFA causes similar skeletal and dentoalveolar effects in hypodivergent and in hyperdivergent patients. The correction of overjet and molar relationship is mainly caused by dentoalveolar changes.Clinical relevanceHyperdivergent patients do not respond unfavorably to FFA treatment compared to hypodivergent patients. Lower incisor protrusion occurs more pronounced in hypodivergent patients. The growth pattern ought to be considered when choosing FFA for class II treatment.

Composite Bite Blocks—An Indigenous, Simple, Fixed Class II Corrector

Fixed functional appliances are used at either the fag end of the growth spurt or after the completion of the same. We orthodontists are yet to come across an appliance which satisfies all the ideal requirements for a fixed functional appliance. Most disadvantages of the fixed functional appliances such as increase in lower anterior facial height, proclination of lower anteriors, constant breakages, and huge expenses were taken into consideration in the basic designing of this ingenious appliance. In this article, a simple fixed functional appliance was designed to function along with fixed appliance therapy to stimulate mandibular growth. After the initial leveling and aligning, 0.019 × 0.025 stainless steel posted arch wires were placed. The bite jumping blocks were fabricated in the upper and lower arches with light cure blue composite. Using indirect bonding trays they were bonded in position. The case finished in an ideal overjet and overbite with a balanced face. Cephalometric values demonstrate an advancement of the mandible.

Driving the maxillary molar distally with infra-zygomatic crest implant: A case report

There has been increase in the treatment modalities for non-surgical Class II malocclusion. This has resulted in orthodontists becoming more vigilant with extraction treatment plans and exploring possible non-extraction treatment approaches. Maxillary molar distalization is one such method. The maxillary molar is distalized to create space and helps in solving the malocclusionMany appliance were used for the distalization of molars over the period of time. Both intra-oral and extra-oral methods are present. The extra oral appliance includes headgear and heavy elastics; whereas intra oral appliance include distal jet, jones jigs, pendulum appliance, k-loop, fixed functional appliances, magnets, ACCO appliance and use of TAD’s. Thus the use of IZC implants has been effective in distalization of molars.

Is PowerScope2 an effective Class II corrector ? A prospective cephalometric study

The study was carried out to evaluate skeletal, dental and soft tissue effects produced by PowerScope 2 appliance following the correction of skeletal Class II malocclusion.A total of 10 patients (3 males and 7 females with mean age of 14.40 ± 0.70 yrs) diagnosed with skeletal Class II malocclusion and indicated for fixed functional appliance were treated using Power Scope2 appliance. Paired t-test was used to assess skeletal, dental and soft tissue changes evaluated on lateral cephalograms taken at pre-functional (T1) and post-functional (T2) stages. Maxillomandibular sagittal relation was markedly improved with a significant gain in the length of the mandible along with a restraining effect on the maxillary dentition. The improvement in molar relation was mainly contributed by dentoalveolar effects (72.3 %) and secondarily by skeletal effects (27.7 %) while the reduction in overjet was contributed by 22.4% skeletal and 77.6% dental effects. Vertical changes were non-significant. Following PowerScope 2 therapy there was an overall improvement in facial esthetics.Power Scope2 serves as an effective skeletal Class II corrector with primarily dentoalveolar and secondary skeletal effects.

Management of deepbite in Class II division 2 malocclusion with two different techniques- A case series

Class II division 2 malocclusion cases are usually challenging to treat with very limited treatment modalities. Growth modification, with the use of functional appliances, is often the ideal treatment in growing patients. In non-growing patients, orthognathic surgery is the treatment of choice, which most patients refuse either due to financial or other concerns. Orthodontic camouflage, with or without extraction is then the only option left, but it also carries a risk of soft tissue compromise, thus management of Class II division 2 cases requires a careful treatment planning. Here, in this case series, we have tried to show the treatment of Class II division 2 cases, with upper premolar extraction and different mechanics, leading to satisfactory post treatment outcomes.

Evaluation of skeletal changes in glenoid fossa, condylar head and articular space following fixed functional appliance therapy using cone beam computed tomography – A clinical prospective study

This study was conducted to evaluate skeletal changes in glenoid fossa, condylar head and articular space following Powerscope appliance therapy using CBCT.This study included twenty patients (age group of 11-15 years) having Class II Division 1 skeletal &amp; dental malocclusion. A pre-treatment CBCT scan (T1) of both TMJs was taken. Following leveling &amp; aligning, Powerscope appliance was inserted, which was sequentially activated using crimpable shims until edge-to-edge bite was obtained. After completion of phase 1 of treatment, another CBCT scan (T2) was taken. Condylar position, length, height, glenoid fossa &amp; articular space measurements were obtained from pre- &amp; post-treatment CBCT scans and data obtained were statistically analysed and compared by Paired-t test.Comparison between T1 &amp; T2 data showed that the condyles were shifted anteriorly by 1.08 mm, condylar length and height increased by 0.26 mm and 0.71 mm, respectively. Glenoid fossa and anterior articular space decreased by 1.50⁰ and 0.23 mm, whereas, middle and posterior articular spaces increased linearly by 2.55 mm and 1.85 mm, respectively.Powerscope shifted the condyle anteriorly, increased its length and height, and reduced the glenoid fossa angle. Anterior articular space decreased whereas middle and posterior articular spaces increased.

The Condylar Effects of Mesenchymal Stem Cells, Low-Level Laser Therapy and Grape Seed Extract on Functional Mandibular Advancement of the Rat Mandible.

Functional treatment of Class II malocclusion is expected to lead to adaptation in the condyle. This study aimed to evaluate the effects of adipose tissue-derived mesenchymal stem cells (ADMSCs), low-level laser therapy (LLLT), and grape-seed extract (GSE) on condylar growth after functional mandibular advancement. Forty-five rats were randomly divided into 8 groups. Functional appliances were applied to all groups (n=6) except the control group (n=3). One group was treated with appliances only; the other six groups received various combinations of ADMSCs, LLLT, and GSE. Analyses for new osteoblasts and new bone formation, vascular endothelial growth factor, and Type II collagen were performed on condylar tissues, after an experimental period of four weeks. The quantitative data obtained from the results of the experiments were evaluated by H-score and analyzed using One-Way ANOVA by Tukey-Kramer multiple comparisons test (p≤0.05). Levels of all investigated parameters increased in all groups (p≤0.05). The highest increases were achieved by a combined application of functional appliance, ADMSCs, LLLT and GSE (p≤0.05). Single LLLT administrations or single GSE applications did not create a statistical difference from appliance alone (p>0.05). A positive effect of ADMSCs or LLLT on osteoblast formation, neovascularization, and Type II collagen level was apparent (p≤0.05), however, neither affected new bone formation (p>0.05). This study shows that ADMSCs with LLLT and GSE applications provide differing levels of new osteoblast and bone formation, new vascular formation, and Type II collagen formation in rat condyles after functional mandibular advancement.