Efficacy of Intra-Articular Injection of Botulinum Toxin Type A (IncobotulinumtoxinA) in Temporomandibular Joint Osteoarthritis: A Three-Arm Controlled Trial in Rats.

Temporomandibular disorders (TMD) are complex pathologies responsible for chronic orofacial pain. Intramuscular injection of botulinum toxin A (BoNT/A) has shown effectiveness in knee and shoulder osteoarthritis, as well as in some TMDs such as masticatory myofascial pain, but its use remains controversial. This study aimed to evaluate the effect of intra-articular BoNT/A injection in an animal model of temporomandibular joint osteoarthritis. A rat model of temporomandibular osteoarthritis was used to compare the effects of intra-articular injection of BoNT/A, placebo (saline), and hyaluronic acid (HA). Efficacy was compared by pain assessment (head withdrawal test), histological analysis, and imaging performed in each group at different time points until day 30. Compared with the rats receiving placebo, those receiving intra-articular BoNT/A and HA had a significant decrease in pain at day 14. The analgesic effect of BoNT/A was evident as early as day 7, and lasted until day 21. Histological and radiographic analyses showed decrease in joint inflammation in the BoNT/A and HA groups. The osteoarthritis histological score at day 30 was significantly lower in the BoNT/A group than in the other two groups (p = 0.016). Intra-articular injection of BoNT/A appeared to reduce pain and inflammation in experimentally induced temporomandibular osteoarthritis in rats.

Quality of Life After Total Temporomandibular Joint Prothesis Surgery.

INTRODUCTION: Total temporomandibular joint (TMJ) prostheses are increasingly used in patients with joint destruction presenting significant pain and mouth opening limitation. This surgery can be considered as the last resort solution whose goal is to restore the mandible function. The aim of this study was to evaluate the patient quality of life (QoL) before and after TMJ replacement surgery with a total TMJ prosthesis, using a modified QoL scale. MATERIALS AND METHODS: All patients with a total uni or bilateral TMJ prosthesis who could be contacted were included. All patients completed 2 retrospective questionnaires: once relative to the preoperative QoL and another for the post-operative QoL, including the assessment of mouth opening limitation, daily eating difficulties and also a QoL score, adapted from the TMJ-QoL questionnaire. RESULTS: A total of 17 patients were included: 13 temporomandibular ankylosis, 3 condylar resorptions and 1 congenital malformation. Mouth opening limitation and daily eating difficulties were significantly reduced after surgery ( P < 0.001). Nine of the 11 QoL questions showed a significant decrease in score and thus an improvement of the QoL after surgery: having a conversation ( P = 0.006), eating ( P < 0.001), yawning ( P < 0.001), sleeping ( P = 0.043), recreational activities ( P = 0.005), relaxing ( P = 0.021), feeling depressed because of TMJ problems ( P = 0.032), daily activities ( P = 0.008) and patient self-assessment of QoL ( P = 0.003). Two showed no significant difference: taking analgesics, and social life. Total score of QoL showed a significant improvement ( P = 0.003). CONCLUSIONS: Quality of life, mouth opening, and daily eating were significantly improved after total TMJ prosthesis, in agreement with the litterature. The TMJ prosthesis could be considered ealier in the management of end-stage temporomandibular disease.

Impacted lower third molar relationship with mandibular angle fracture complications.

INTRODUCTION: Mandibular angle fractures are very common and are associated with the highest risk of complications. The aim of this study is to evaluate the correlation between impacted lower third molar and mandibular angle fracture complications. MATERIAL AND METHODS: All patients presenting with a mandibular angle fracture and at least 2 months follow up were retrospectively included. The following complications were recorded: post-traumatic malocclusion, mouth opening limitation, inferior alveolar nerve hypoesthesia, infection, delayed union, hardware loosening. The patients were divided in two groups: impacted lower third molar or erupted/absent lower third molar. RESULTS: A total of 68 patients were included, lower third molar was impacted in 36 cases and erupted/absent in 32 cases. 40 complications were recorded in 27 patients at 2 months. No statistically significant difference could be found about malocclusion, mouth opening limitation and inferior alveolar nerve hypoesthesia. A lower rate of persistent inferior alveolar nerve hypoesthesia (p = 0.0557) in patients with impacted lower third molar (19.4%) was observed compared to patients without impacted lower third molar (40.6%). There was no occurrence of delayed union and hardware loosening in impacted lower third molar group, whereas 5 delayed unions and 4 hardware loosening were recorded in erupted/absent lower third molar group. Finally, the rate of patients with at least one of the 6 complications is significantly higher in the erupted/absent lower third molar group (17/32, 53.1%) than in the impacted lower third molar group (10/36, 27.8%), p = 0.033. DISCUSSION: The risk of overall complication is decreased when lower third molar is impacted in mandibular angle fracture. This supports the idea of a role of the impacted lower third molar in fracture reduction and stability.