Evaluation of the contribution of different groups of teeth to occlusion of patients with symptoms of temporomandibular disorders.

PURPOSE: The purpose of this study was to analyse the distribution of occlusal forces in the dental arches released during tooth clenching in patients with symptoms of temporomandibular disorders, and to analyse the age and gender structure of the patients in the study group and the control group. MATERIALS AND METHOD: The study was carried out on a group of 58 patients, of both genders, aged 18-40 years, with full dental arches, who presented for treatment at the Prosthodontics Clinic of the University Dental Clinic in Kraków due to symptoms of temporomandibular disorders. The patients were divided into two groups. The first group (study group) comprised 26 patients with painful temporomandibular disorders, while the second group (control group) comprised 32 patients without pain. The study only included patients over 18 years of age, with full dental arches with symptoms of temporomandibular disorders. All patients underwent a basic dental examination and a specialized functional examination of the masticatory organ. A T-Scan III-Novus instrument with electronic occlusal articulation paper was used to assess the distribution of occlusal contacts. RESULTS: In the study, women (43) were a larger group than men (15). Statistically significant values for the percentage distribution of occlusal contacts were obtained in group of women in the study group on the right and left side, in the area of molars and premolars. In the analysis of the percentage distribution of occlusal contacts in both the study and control groups, it can be seen that the first molars (teeth 16 and 26) showed a larger percentage range of values than the other teeth. The smallest values can be observed on the second incisal teeth and on the canines. CONCLUSIONS: The first molars are, in the majority of patients, the teeth on which the strongest occlusal contacts are generated. Excessive participation of incisal teeth in occlusion might influence the development of the pain form of TMD. In order to determine whether there is a correlation between an uneven distribution of occlusal contacts and TMD pain, studies on larger numbers of patients are needed. © 2024 Australian Dental Association.

Development of a novel in vivo corneal fibrosis model in the dog.

The aim of this study was to develop a novel in vivo corneal model of fibrosis in dogs utilizing alkali burn and determine the ability of suberanilohydroxamic acid (SAHA) to inhibit corneal fibrosis using this large animal model. To accomplish this, we used seven research Beagle dogs. An axial corneal alkali burn in dogs was created using 1 N NaOH topically. Six dogs were randomly and equally assigned into 2 groups: A) vehicle (DMSO, 2 µL/mL); B) anti-fibrotic treatment (50 µM SAHA). The degree of corneal opacity, ocular health, and anti-fibrotic effects of SAHA were determined utilizing the Fantes grading scale, modified McDonald-Shadduck (mMS) scoring system, optical coherence tomography (OCT), corneal histopathology, immunohistochemistry (IHC), and transmission electron microscopy (TEM). The used alkali burn dose to produce corneal fibrosis was well tolerated as no significant difference in mMS scores between control and treatment groups (p = 0.89) were detected. The corneas of alkali burned dogs showed significantly greater levels of α-smooth muscle actin, the fibrotic marker, than the controls (p = 0.018). Total corneal thickness of all dogs post-burn was significantly greater than baseline OCT images irrespective of treatment (p = 0.004); TEM showed that alkali burned corneas had significantly greater minimum and maximum interfibrillar distances than the controls (p = 0.026, p = 0.018). The tested topical corneal alkali burn dose generated significant opacity and fibrosis in dog corneas without damaging the limbus as evidenced by histopathology, IHC, TEM, and OCT findings, and represents a viable large animal corneal fibrosis in vivo model. Additional in vivo SAHA dosing studies with larger sample size are warranted.

Measurement of occlusal forces in the therapy of functional disorders with the use of botulinum toxin type A.

Functional disorders of the stomatognathic system include dysfunctions leading to pathological increase of the occlusal forces generated by mandibular adductors. High values of these forces are the cause of numerous disorders within the masticatory organ such as pathological abrasion of the teeth, tension headaches and pain in the region of the temporomandibular joints. The aim of this study was assessment of occlusal forces in the course of the therapy of painful types of functional disorders with the use of botulinum toxin type A - the drug causing muscle relaxation. The material for the study comprised adult patients aged 24-42 years who presented with a painful type of functional disorders in the University Hospital, Institute of Dentistry Jagiellonian University Medical College in Cracow. The patients were qualified to the study on the basis of the results of specialist functional examination of the masticatory organ in which additionally the VAS (Visual Analogue Scale) was used for pain assessment of the masseters and temporomandibular joints. The measurement of maximal occlusal forces in the examined patients was carried out in all patients in the region of the central incisors and first molars on the both side with the use of a special measuring instrument for dental examination, specially constructed (patent number P 334933). The examinations were performed before the beginning of the treatment, 10 days and 16 weeks after intramuscular administration of botulinum toxin type A at a dosage of 21 mouse units - U for one masseter. The results of the examination of maximal occlusal forces obtained in the first examination, that is, before the beginning of the treatment, markedly exceeded the physiological values. In the control examinations, significant, persistent decrease of the studied forces has been noted.

Experimental research on the possibilities of maintaining thermal conditions within the limits of the physiological conditions during intraoral preparation of dental implants.

The objective of the study was to evaluate the degree of temperature change in the bone, directly adjacent to the implant site during the abutment part of one-piece implants, during procedures involving different cutting techniques. Three different one-piece implants: Osteoplant, Nobel Direct, Q-implant were cut with air-turbine burs after insertion in fresh pig ribs. Tests were performed with a variety of cooling techniques including air and air-liquid coolant. Implants were cut on the occlusal and axial surfaces of the abutment part. The temperature changes were evaluated using thermocouple type K during and after cutting procedures. It was found that regardless of the cutting technique, the temperature of the bone always increased during the cutting procedure. The critical temperature threshold Delta T=10 degrees C (47 degrees C) was always exceeded, when only the air coolant was used, although when the air-water spray coolant was utilized during the cutting procedure, it prevented the temperature to exceed this critical level. The extent of thermal changes in the bone depends on the cutting technique. Constant air-water cooling during the cutting procedure is a recommended technique in order to avoid overheating the implant-bone interface. The dry cutting technique, using only an air coolant, should be avoided as it can induce sufficiently high thermal damage in the bone adjacent to the implant, which leads to compromise of the osteointegration process.