Simultaneous standard total joint prosthesis reconstruction with SSRO and Le Fort I osteotomy in the treatment of unilateral temporomandibular joint ankylosis with jaw deformity: a case cohort study.

OBJECTIVE: Unilateral temporomandibular joint ankylosis with jaw deformity (UTMJAJD) may require simultaneous total joint prosthesis (TJP) reconstruction, sagittal split ramus (SSRO), and Le Fort I osteotomies. The purpose of this study was to evaluate outcomes in patients treated with these procedures. METHODS: Patients diagnosed UTMJAJD between 2016 and 2018 were selected for the study. Mandible-first procedure was performed after ankylosis release with TJP on the ankylosed side and SSRO on the contralateral side. Le Fort I osteotomy with and without genioplasty was lastly performed. Maximal incisor opening (MIO), facial symmetry, and jaw and condyle stability were compared before, after operation, and during follow-ups. RESULTS: Seven patients were included in the study. Their average chin deviation was 9.5 ± 4.2 mm, and maxillary cant was 5.1 ± 3.0°. After operation, jaw deformity significantly improved, with chin deviation corrected 7.6 ± 4.1 mm (p = 0.015) and advanced 5.9 ± 2.5 mm (p = 0.006). After an average follow-up of 26.6 ± 17.1 months, MIO significantly increased from 11.4 ± 9.3 to 35.7 ± 2.6 mm (p = 0.000). The occlusion was stable with no significant positional or rotational changes of the jaw (p > 0.05). There was no obvious condylar resorption during follow-ups. CONCLUSION: Simultaneous TJP reconstruction, SSRO, and Le Fort I osteotomy are reliable and effective methods for the treatment of UTMJAJD.

Comparison of disc position stability and condylar bone remodelling between two open disc repositioning surgeries: a retrospective single-centre cohort study.

BACKGROUND AND OBJECTIVE: Open suturing (OSu) and mini-screw anchor (MsA) are two commonly used open disc repositioning surgeries for anterior disc displacement (ADD) of the temporomandibular joint (TMJ). This study assesses the differences in disc position stability (DPS) and condylar bone remodelling (CBR) between these two surgical procedures in a single centre. METHODS: A retrospective cohort study using MRI scans (pre-operation, 1 week and 12 months post-operation) of all patients who had open TMJ disc repositioning surgery from January 2016 to June 2021 at one centre through two surgical techniques (OSu and MsA) was performed. The predictor variable was technique (OSu and MsA). Outcome variables were DPS and CBR. During follow-up, DPS was rated as good, acceptable and poor, and CBR was graded as improved, unchanged, and degenerated. Multivariate analysis was used to compare the DPS and CBR at 12 months after adjusting five factors including age, sex, Wilkes stage, preoperative bone status (normal, mild/moderate abnormal) and the degree of disc repositioning (normal, overcorrected, and posteriorly repositioned). Relative risk (RR) for DPS and CBR was calculated by multivariate logistic regression. RESULTS: Three hundred eighty-five patients with 583 joints were included in the study. MRIs at 12 months showed that 514 joints (93.5%) had good DPS, and 344 joints (62.5%) had improved CBR. Multivariate analysis revealed that OSu had higher DPS (RR=2.95; 95% CI, 1.27-6.85) and better CBR (RR=1.58; 95% CI, 1.02-2.46) than MsA. Among the factors affecting DPS, females had better results than males (RR=2.63; 95% CI, 1.11-6.26) and overcorrected or posteriorly repositioned discs were more stable than normally repositioned discs (RR=5.84; 95% CI, 2.58-13.20). The improvement in CBR decreased with age increasing (RR=0.91; 95% CI, 0.89-0.93). Preoperative mild/moderate abnormal bone status had a higher probability of improved CBR compared to normal preoperative bone status (RR=2.60; 95% CI, 1.76-3.83). CONCLUSION: OSu had better DPS and CBR than MsA. Sex and the degree of disc repositioning impacted DPS, while age and preoperative bone status affected CBR.

Analysis of joint protein expression profile in anterior disc displacement of TMJ with or without OA.

OBJECTIVE: Anterior disc displacement (ADD) is a common clinical issue and may cause osteoarthritis (OA). However, the research of protein changes in synovial fluid as disease development marker and potential treatment clue is still insufficient. MATERIALS AND METHODS: We conducted the high-resolution mass spectrometry (MS) of synovial fluid collected from 60 patients with normal disk position to ADD and ADD with osteoarthritis (OA). The proteins with significant changes among the 3 groups were analyzed by biological information and further validated by in primary rat condyle chondrocytes and OA animal model. RESULTS: FGL2, THBS4, TNC, FN1, OMD etc. were significantly increased in ADD without OA (p < 0.05), which reflected the active extracellular matrix and collagen metabolism. FGFR1, FBLN2, GRB2 etc. were significantly increased in ADD with OA group (p < 0.05), which revealed an association with apoptosis and ferroptosis. Proteins such as P4HB, CBLN4, FHL1, VIM continuously increase in the whole disease progress (p < 0.05). Both the in vitro and in vivo results are consistent with protein changes detected in MS profile. CONCLUSION: This study firstly provides the expression changes of proteins from normal disc condyle relationship toward ADD with OA, which can be selected and studied further as disease progress marker and potential treatment targets.

Bioinspired phosphorus-free and halogen-free biomass coatings for durable flame retardant modification of regenerated cellulose fibers.

Inspired by mussel adhesion and intrinsic flame retardant alginate fibers, a biomass flame retardant (PPCA) containing adhesive catechol and sodium carboxylate structure (-COO-Na+) based on biomass amino acids and protocatechualdehyde was designed to prepare flame retardant Lyocell fibers (Lyocell@PPCA@Na). Furthermore, through the substitution and chelation of metal ions by PPCA in the cellulose molecular chain, flame retardant Lyocell fibers chelating copper and iron ions (Lyocell@PPCA@Cu, Lyocell@PPCA@Fe) were prepared. Compared with the original sample, the peak heat release rate (PHRR) and total heat release (THR) for modified Lyocell fibers were significantly reduced. In addition, the modified sample exhibited a certain flame retardant durability. TG-FTIR analysis showed that the release of flammable gaseous substances was inhibited. The introduction of Schiff bases and aromatic structures in PPCA, as well as the decomposition of carboxylic metal salts were beneficial for the formation of char residue containing metal carbonates and metal oxides to play the condensed phase flame retardant effect. This work develops a new idea for the preparation of eco-friendly flame retardant Lyocell fibers without the traditional flame retardant elements such as P, Cl, and Br.

Temporomandibular joint disc repositioning and occlusal splint for adolescents with skeletal class II malocclusion: a single-center, randomized, open-label trial.

BACKGROUND: Temporomandibular joint (TMJ) disc repositioning through open suturing (OSu) is a new disc repositioning method. Its result for adolescents with condylar resorption and dentofacial deformities combined with and without postoperative occlusal splints (POS) has not been well studied. OBJECTIVE: This study was to evaluate and compare the effects of OSu with and without POS in the treatment of TMJ anterior disc displacement without reduction (ADDwoR) in adolescent skeletal Class II malocclusion. METHODS: A total of 60 adolescents with bilateral ADDwoR were enrolled in this study. They were randomly allocated into two groups: OSu with and without POS. Magnetic resonance imaging (MRI) and lateral cephalometric radiographs were used to measure changes in condylar height and the degree of skeletal Class II malocclusion from before operation and at 12 months postoperatively. Changes in these indicators were compared within and between the two groups. RESULTS: After OSu, both groups exhibited significant improvements in condylar height and occlusion at the end of 12 months follow-up (P < 0.05). The group of OSu with POS had significantly more new bone formation (2.83 ± 0.75 mm vs. 1.42 ± 0.81 mm, P < 0.001) and improvement in dentofacial deformity than the group of OSu only (P < 0.05). The new bone height was significantly correlated with POS (P < 0.001), the changes of SNB (P = 0.018), overjet (P = 0.012), and Wits appraisal (P < 0.001). CONCLUSION: These findings indicated that OSu can effectively stimulate condylar regeneration and improve skeletal Class II malocclusion in adolescents with bilateral ADDwoR. The results are better when combined with POS. TRIAL REGISTRATION: This trial was prospectively registered on the chictr.org.cn registry with ID: ChiCTR1900021821 on 11/03/2019.

Heterotopic ossification after alloplastic temporomandibular joint replacement: a case cohort study.

BACKGROUND: Heterotopic ossification (HO) is one of the serious complications leading to the failure of alloplastic temporomandibular joint replacement (TJR). However, there was few research on its exact incidence and occurrence. Severe HO might result in pain and limited mouth opening after surgery. Therefore, it is necessary to clarify its clinical and imaging manifestations. The purpose of this study was to study the occurrence and classify HO after the alloplastic TJR. METHOD: Patients who underwent standard TJR (Zimmer Biomet stock prostheses or Chinese stock prostheses) with fat graft and at least 1-year-follow-up were included. HO was classified into 4 types according to postoperative computed tomography (CT) scans. Type and occurrence in different TMJ disease were compared. Joint space within 1 week after operation was measured and compared between HO and non-HO TJRs. Maximum incisal opening (MIO), pain, and quality of life (QoL) were recorded and their relevance with HO was analyzed statistically. RESULT: 81cases with 101 joints were included in the study. The mean follow-up time was 22.9 months (12 ~ 56 months). Among the 48 joints, 27 (56.3%) were type I (bone islands); 16 (33.3%) were type II (bone spurs from the mandibular ramus); 3 (6.3%) were type III (bone spurs from the fossa); and 2 (4.2%) were type IV (bone spurs from both the mandibular ramus and fossa). In HO patients, joint space in type IV was smaller than the other 3 types. Pain scores in HO were significantly greater than non-HO patients before and after operations (p < 0.05). 1 patient in Type IV HO developed ankylosis and had prosthesis revision which accounted for 2.1% in HO patients and 1.0% in all TJR patients. CONCLUSION: HO after alloplastic TJR with fat graft was not severe except for type IV, which was easy to cause ankylosis. Preserving sufficient TJR space was important for ankylosis prevention.

Disc repositioning by open suturing vs. mini-screw anchor: stability analysis when combined with orthognathic surgery for hypoplastic condyles.

BACKGROUND: Disc repositioning by Mitek anchors for anterior disc displacement (ADD) combined with orthognathic surgery gained more stable results than when disc repositioning was not performed. But for hypoplastic condyles, the implantation of Mitek anchors may cause condylar resorption. A new disc repositioning technique that sutures the disc to the posterior articular capsule through open incision avoids the implantation of the metal equipment, but the stability when combined with orthognathic surgery is unknown. The purpose of this study was to evaluate the stability of temporomandibular joint (TMJ) disc repositioning by open suturing in patients with hypoplastic condyles when combined with orthographic surgery. METHODS: Patients with ADD and jaw deformity from 2017 to 2021 were included. Disc repositioning by either open suturing or mini-screw anchor were performed simultaneously with orthognathic surgery. MRI and CT images before and after operation and at least 6 months follow-ups were taken to evaluate and compare the TMJ disc and jaw stability. ProPlan CMF 1.4 software was used to measure the position of the jaw, condyle and its surface bone changes. RESULTS: Seventeen patients with 20 hypoplastic condyles were included in the study. Among them, 12 joints had disc repositioning by open suturing and 8 by mini-screw anchor. After an average follow-up of 18.1 months, both the TMJ disc and jaw position were stable in the 2 groups except 2 discs moved anteriorly in each group. The overall condylar bone resorption was 8.3% in the open suturing group and 12.5% in the mini-screw anchor group. CONCLUSIONS: Disc repositioning by open suturing can achieve both TMJ and jaw stability for hypoplastic condyles when combined with orthognathic surgery.

Stability of the contralateral temporomandibular joint disk position after disk repositioning on one side.

OBJECTIVE: To evaluate the stability of the contralateral temporomandibular joint disk position after disk repositioning on 1 side. STUDY DESIGN: Patients with unilateral anterior disk displacement (ADD) treated by disk repositioning from 2015 to 2019 were included in the study. The contralateral disk status was classified as follows: normal, ADD with reduction (ADDwR), and medial/lateral displacement. At 1-year follow-up, changes in the contralateral disk position were evaluated by MRI. RESULTS: Two hundred thirty-four patients were included in the study. There were 84 disks with normal position, 51 with ADDwR, and 99 with medial/lateral displacement (M/LD) in the contralateral joint. At 1-year follow-up, all the repositioned disks were stable without relapse. In the contralateral joints, 75% of the disks with normal position were unchanged compared with 43.1% of the ADDwR and 54.5% of the M/LD. ADDwR had the highest rate of changing to ADDwoR compared with the disks in normal position (4.8%) and M/LD (7.1%, χ2 = 16.13, P < .001). There were 28.3% of M/LD disks and 3.9% of ADDwR that changed to normal position. CONCLUSIONS: After unilateral disk repositioning, most of the contralateral disks with normal position were stable. M/LD disks tended to move to normal position, whereas ADDwR was largely changed to ADDwoR.

The Effect of Condylar Regeneration After Different Disc Repositioning Surgeries in Adolescents with Skeletal Class II Malocclusion.

PURPOSE: To evaluate the effect of different temporomandibular joint (TMJ) disc repositioning surgeries for the treatment of anterior disc displacement (ADD) in juvenile patients with skeletal Class II malocclusion. PATIENTS AND METHODS: Patients (< 20 years, cervical vertebral maturation stage, IV-V) who had bilateral TMJ ADD with skeletal Class II malocclusion were treated by disc repositioning surgery (mini-screw anchor, [MsA]; or opening suturing, [OSu]). Magnetic resonance imaging (MRI) and lateral cephalometric films before and more than 12 months after surgery were collected from all patients. Changes of SNA, SNB, ANB, incisor overjet, pogonion position (pg'-G'), and condylar height were measured before and after surgery in different disc reposition surgeries and compared by statistical analysis. RESULTS: Eighty-four patients with an average age of 16.44 years and follow-up time of 14.60 months (12 to 33 months) were included in the study. Among them, 16 patients had a mean follow-up of 14.8 months without treatment before disc repositioning. Their condylar height was significantly decreased (P = .004) by MRI measurement. Six patients who had cephalometric films showed significantly decreased SNB (P = .042) and increased overjet (P = .037). After disc repositioning by either OSu (54 cases) or MsA (30 cases), condylar height, SNB were significantly increased and overjet, Pg'-G', ANB were decreased in both groups (P < 0.001). There was more new bone height in OSu than MsA (P = .004), but no significant differences in SNB, ANB, overjet and Pg'-G' between the 2 groups (P > .05). The new bone height was significantly correlated with the surgical method (P = .029), age (P = .015), SNB (P = .008), overjet (P = .048) and pg'-G' (P = .001). CONCLUSIONS: Both types of disc repositioning method can effectively promote condylar regeneration and improve skeletal Class II malocclusion in adolescents with ADD. Disc repositioning by OSu obtained more new bone height than MsA.

Preliminary Study of Standard Artificial Temporomandibular Joint Replacement With Preservation of Muscle Attachment.

PURPOSE: To evaluate the effect of preserving the muscle attachments when performing standard artificial temporomandibular joint replacement (TJR). PATIENTS AND METHODS: The clinical and radiological imaging data of patients who underwent standard artificial TJR with and without preservation of lateral pterygoid muscle (LPM) and masseter muscle attachments from January 2017 to December 2019 were collected. The maximum interincisal opening (MIO), lateral excursions and protrusion distances, visual analogue scale (VAS) scores of pain, diet, and quality of life (QoL) were recorded before the operation, and 1, 3, 6, and 12 months after the operation. The volumes of LPM and masseter muscles were measured and analyzed by computed tomography (CT) scans. RESULTS: Twenty-seven patients with 36 joints were included in the study. Among them, 11 joints had muscle attachment preserved, and 25 had no muscle attachment preserved. After surgery, the MIO, lateral excursions, and scores of diet, pain, and QoL in the preserved muscle attachment group were significantly better than those in the unpreserved group (P < .05). The measurement volumes of LPM and masseter muscles in the preserved group were significantly larger than that in the unpreserved group (P < .05). Changes of lateral excursion from the TJR side with and without LPM preservation were statistically correlated with the LPM volume (P < .05). CONCLUSION: Preserving muscle attachment for the standard artificial TJR is beneficial to the recovery of postoperative mandibular function.

Preliminary clinical study of Chinese standard alloplastic temporomandibular joint prosthesis.

PURPOSE: To evaluate the preliminary clinical outcomes on the Chinese standard temporomandibular joint (TMJ) prostheses. PATIENTS AND METHODS: Patients who underwent Zimmer Biomet and Chinese standard prostheses by one surgeon between January 1st 2016 and June 30th 2017 were included in the study. Maximum incisal opening (MIO), pain, diet, and joint function were measured; CT scans were taken before and after the operation and during at least a 12-months follow-up for evaluation. RESULTS: Thirty-five patients including 12 with Chinese standard prostheses and 23 with Biomet stock prostheses participated in the study. After an average of 14.3 months follow-up, both types of prostheses could significantly improve MIO, diet, and joint function, and relieve pain (p < 0.05). There were no significant differences in diet, pain level and joint function either before or after the operation between the two types of prostheses, whereas after the operation, the MIO with Chinese standard prostheses was significantly larger than with the Biomet stock prostheses (p < 0.05). However, there was no significant difference before operation (p > 0.05). A computed tomography (CT) scan showed that no prostheses dislocated or broke, no screws loosened, and ectopic bone formation appeared around the alloplastic condyle. CONCLUSION: Chinese standard TMJ prostheses are effective and stable in clinical application. They can significantly improve mouth opening, diet, and joint function and relieve pain.

Comparison of bone adaptation after modification in biomet standard alloplastic temporomandibular joint prostheses.

PURPOSE: The aim of the study was to compare bone adaptation after design modification in Biomet stock prostheses. MATERIALS AND METHODS: Computed tomography (CT) data of the patients treated with a Biomet TMJ replacement from 2010 to 2016 were recruited. Fossa prosthesis with a bulge and 4 types of condyle-ramus angle prostheses were virtually designed and implanted by computer-assisted simulation. The amount of bone trimming including fossa, mandibular ramus and bone graft were measured by ProPlan CMF 1.4 software. The differences between the original and modified prostheses were compared by SPSS 17.0 software for statistical analysis. RESULTS: There were 54 patients' CT data included in the study. The amount of fossa bone trimming was 150.20 mm3 in the modified prosthesis and 281.82 mm3 in the original one. The amount of ramus bone trimming was 103.86 mm3 in the modified prosthesis and 229.45 mm3 in the original one. The amount of fossa bone grafting was 95.88 mm3 in the modified prosthesis and 263.03 mm3 in the original one. There were significant differences between them (p = 0.000). CONCLUSIONS: The modified Biomet prostheses design requires less bone trimming and grafting for implantation.

Clinical and Radiologic Follow-Up of Zimmer Biomet Stock Total Temporomandibular Joint Replacement After Surgical Modifications.

PURPOSE: The aim of this study was to evaluate the clinical and radiologic results of Zimmer Biomet stock prostheses (Jacksonville, FL) in temporomandibular joint replacement after surgical modifications during at least 1 year of follow-up. PATIENTS AND METHODS: We recruited patients treated by Zimmer Biomet stock prostheses after technical modifications, including digital templates, autogenous ipsilateral bone grafting from the mandible to the fossa, salvaging of the disc remnant and suturing it to the medial aspect of the prosthesis, and fat grafts from a retromandibular incision, between 2010 and 2016. Clinical examination findings including maximal incisal opening; visual analog scale scores for pain, diet, and mandibular movement; and quality of life were compared before the operation and at least 1 year postoperatively. The status of the fossa bone graft was evaluated by computed tomography examination. RESULTS: The study comprised 38 joints in 33 patients with diagnoses including osteoarthritis, ankylosis, and neoplasm. Compared with before the operation, maximal incisal opening and visual analog scale scores for diet, function, and pain level, as well as the quality-of-life survey score, were considerably improved during the last follow-up. Computed tomography scans showed all bone grafts were completely healed within the fossa 1 year after surgery. There was no ectopic bone formation, screw loosening, or component displacement or breakage. CONCLUSIONS: Our surgical modifications of Zimmer Biomet stock prostheses showed good results for at least 1 year of follow-up.

3-D computed tomography measurement of mandibular growth after costochondral grafting in growing children with temporomandibular joint ankylosis and jaw deformity.

OBJECTIVE: The aim of this study was to evaluate the long-term results after costochondral grafting (CCG) in growing children with temporomandibular joint ankylosis and jaw deformity by 3-dimensional computed tomography (CT) measurement. STUDY DESIGN: Patients with unilateral TMJ ankylosis and jaw deformity treated by CCG from 2010 to 2014 were evaluated. Their CT data within 1 week after operation and after at least 2 years of follow-up were analyzed using ProPlan CMF 1.4 software. Maximal incisal opening (MIO), condyle-ramus heights, chin deviation, and growth of CCG were measured and compared before and after the operation and at the last follow-up. SPSS 17.0 software was used for statistical analysis. RESULTS: Seven patients were included in the study. The mean follow-up period was 46.4 months. Five of 7 patients treated with this protocol experienced good mouth opening and symmetric mandibular growth. One patient achieved good mouth opening but not symmetric growth, and 1 patient experienced ankylosis again. CONCLUSIONS: CCG can be a reliable method to treat temporomandibular joint ankylosis with jaw deformity in growing children. Continued growth occurs in the children, but long-term outcomes require further investigation.