Electromyographic activity of the masseter muscle in individuals with group function and canine guidance

Background. There is no general consensus in restorative dentistry about which lateral guidance should be established. Some studies have shown that canine guidance decreases the tension of masticatory muscles. Others have reported that group function might achieve a better physiologic distribution of occlusal forces. Also, some reports have shown that both guidances are equally acceptable. Despite all discussions, clinical evidence of one guidance being superior to another is limited. Thus, this study aimed to analyze the electromyographic (EMG) activity of masseter muscles in individuals with group function and canine guidance. Methods. Twenty volunteers of both genders, aged 20-25, were divided into two groups: GF (group function guidance, n=10) and CA (canine guidance, n=10). EMG activity of masseters was captured using surface electrodes during habitual maximum intercuspation (HMI) and right and left lateral jaw movements and recorded using EMG amplitude values (RMS – root means square). Student’s t-test was used to compare mean RMS values between the groups and lateral movements in each group. Results. During HMI, there was no difference in masseter EMG activity between the groups. Both masseters showed higher activity in group GF only on the right side during lateral movements, while the left masseter exhibited higher activity on the nonworking side in both groups. The activity of both masseters distributed by tooth was higher in group CA. Conclusion. During tooth restorative procedures, any guidance is acceptable considering HMI. However, group function guidance is more favorable during lateral movements due to greater dissipation of occlusal pressures.

Pressure Algometry Evaluation of Two Occlusal Splint Designs in Bruxism Management-Randomized, Controlled Clinical Trial

The aim of this pilot study was to evaluate the short-term effectiveness of two different occlusal devices and their impact on the pressure pain threshold (PPT) values among patients who reported to the Dental Prosthetics Outpatient Clinic of Pomeranian Medical University (Szczecin, Poland) and who were diagnosed with probable bruxism. Two groups were formed (A and B) to which patients were assigned randomly. Each group used a different occlusal splint for bruxism management. The occlusal appliance by Okeson, or the bimaxillary splint, was used overnight by each patient for 30 days of the study. The PPT was measured twice, at the first visit and after 30 days of using each occlusal device, with Wagner Paintest FPX 25 algometer. Bruxism was diagnosed based on data from the patient’s medical history and from the physical examination. Nocturnal Bruxism Criteria according to the International Classification of Sleep Disorders (Third Edition) was used for the patient’s evaluation. Results: similar pain factor (PF) reduction was observed in both the examined groups, regardless of the device used; canine guidance and no guidance were similarly effective in terms of increasing pain resilience.

CLINICALEFFECTIVENESS OF OCCLUSALSPLINTS IN PATIENTS WITH FUNCTIONAL OCCLUSAL PROBLEMS

Occlusal disorders caused by missing teeth and without timely and proper treatment, lead to poorly diagnosed pathology of the masticatory muscles and the temporomandibular joint. Our study included 31 patients with dental defects, impaired canine guidance, and TMJ pathology. With a specifically developed computer program we accomplished the differentiation of various degrees of muscle and joint dysfunction in the temporomandibular joint. The results obtained by examining the patients prior to, and after the treatment, provide evidence to the effect that the modified occlusal splint has on the upper jaw.

Forensic studies with human analogues: evaluation of decomposition and the use of residual odor detection dogs

This book is the product of the research group “Sniffing Knowledge” which belongs to the School for Canine Guidance and Training of the National Police of Colombia, in collaboration with the Institute of Forensic Sciences of the Texas Technological University (TTU). Chapter 1 includes experiments with human analogues (Sus Scrofa) detectable by canine teams, evaluating the sensitivity and specificity of the findings at sites where a corpse was found by means of a double blind test. The test is carried out in order to determine the existence of residual odor. It also validates the response of the dog and itshandler using unmanned aerial devices and uses dogs who were certified with human bone remains. Chapter 2 analyzes the effects of the external envelope of pigs against the rate of decomposition in order to understand, in real practice when a body is discovered at a crime scene, if such information is crucial for criminal investigators to be able to establish the Post Mortem Interval (IPM). The academic and experimental approach analyzes tangent efforts to present possible solutions to corpse inspection procedures or the possible sites associated with the events in which a person might die. To conclude, it articulates different fields of knowledge within the forensic sciences applied with canines, allowing high reliability for the subsequent approach in real operational work of missing persons or in cases of homicide in order to have an impact on the crimes that affect coexistence and citizen security in Colombia.

EVALUATION OF CEPHALOMETRIC ANALYSIS IN PATIENTS WITH BILATERAL CONDYLAR RETROPOSITION IN TEMPOROMANDIBULAR DYSFUNCTION

Relevance. During the dentoalveolar growth and development, the direction and growth type of facial skull play a very important role. Development of esthetical symmetry, functional relationship, and clinical disharmony depends on skull parameters. Temporomandibular joint dysfunction is one of the most common diseases nowadays. That is why early identification of risk factors is among the priorities. This study aimed at evaluating occlusional and skeletal specific characteristics in patients with temporomandibular joint dysfunction, comparing different cephalometric findings and CT findings relating to condylar position. Materials and methods. The study included 45 individuals. The study group consisted of 26 patients with bilateral condylar retroposition. Control group was made up of 19 patients. The participants underwent clinical examination, functional testing, palpation of masticatory muscles, occlusion diagnosis by applying Baush articulating film 200,100,8 microns, cephalometric analysis: Tweed, Kim, Jarabak, Ricketts, computed tomography of temporomandibular joint. Statistical analysis was carried out by the program IBM SPSS Statistic Base v.22. Results. There were no pathological contacts during evaluation of static and dynamic occlusion, laterotrusion as «canine guidance». The patients of the test group had bilateral posterior joint fissure reduced right-median 1,96, left-median 1,81. In control group the position was right-average 2,75 and left-median 2,67 The patients in the control and test groups the indices Tweed <FMA average were 19,6°/ median 21,7°; <IMPA average 97,9°/ median 97,8°; Kim ODI median was 68,9°/73,74°; Ricketts Overbite median 2.1 mm /1,9 mm, Overjet median was 2,9 mm /2,85 mm, PM-Xi-ANS median was 44,1°/43,75°, <NPog-FH median was 91°/86,85°,<NBa-PtGn median was 91,1°/90,1°, <MeGo-FH median was 18,7°/22,4°; Jarabak <N-S-Ar average was 127,2°/125,6 °. Conclusions. In the patients with bilateral condylar retropositionm the joint fissure is reduced. Cephalometric analysis demonstrated the following: Tweed <FMA, <IMPA; Kim ODI; Ricketts Overbite, Overjet, PM-Xi-ANS, <MeGo-FH; Jarabak <N-S-Ar can not be used as diagnostic criteria of bilateral condylar retroposition. Ricketts <NPog-FH in the test group showed the mandibular retroposition, but with normal type of mandibular growth <NBa-PtGn. It can be used as one of the primary cephalometric diagnostic indicator of bilateral condylar retroposition.