Ethiopathogenic mechanism involved in bruxism

Rezumat. Sub denumirea de bruxism este cunoscută parafuncţia ce are drept consecinţă uzura pronunţată a arcadelor dentare, tulburări ale muşchilor masticatori şi ale articulaţiei temporo–mandibulare. La inceputul secolului trecut, Karolyi, apoi Marie şi Pietkiewicz scriau că “scrâşnitul dinţilor reuneşte de asemenea leziuni ale sistemului nervos central” şi propuneau termenul de bruxomanie. Termenul de bruxomanie a fost utilizat, în 1907, în Franţa de către Marie şi Pietkecwicz, iar termenul de bruxism, acceptat şi astăzi, a fost utilizat în literatura de specialitate pentru prima dată de Frohman în 1931, pentru a denumi scrâşnirea şi frecarea nefuncţională a dintilor. Etiologia bruxismului constituie subiectul unor inepuizabile dezbateri. Pe plan international, din datele recent publicate in literatura de specialitate se observa un consens in ceea ce priveste o implicare multifactoriala (Lobbezoo, 2001) in mecanismele patogenice ale bruxismului. Primele opinii privind etiologia bruxismul au avut in vedere contactele dento-dentare si patologia contractiilor muusculare. Ideile au evoluat pana la implicarea factorilor comportamentali si in special a aspetelor legate de somn(Brocard, 2007). Attanasio R.(1991) si Lobbezo si colab(2006) citati de Leonardo Lopez do Nascimento si colab. in 2008 arata ca etiologia bruxismului nocturn implica factori locali, sistemici, psihologici si ereditari. Prezenta lucrare realizează o trecere în revistă a principalelor mecanisme etiologice implicate în producerea şi întreâinerea beuxismului.Summary. Bruxism stands for the parafuncion resulted from the pronounced wear of dental arches, disorders of jaw muscles and of temporo–mandibular joint. At the beginning of XXth century, Karolyi, and then Marie and Pietkiewicz wrote that “teeth gnash also hold lesions of central nervous system” and proposed the term of „bruxomanie”. The term of „bruxomanie” was used, in 1907, in France by Marie and Pietkecwicz, whilst the term of „bruxism”, accepted today, was used in literature for the first time by Frohman in 1931, to name teeth gnashing and non-functional rubbing. Etiology of „bruxism” is an inexhaustible subject of debates. Internationally, the recent data published in literature offer a consensus regarding the multifactorial involvement (Lobbezoo, 2001) in the pathogenic mechanisms of bruxism. The first views on the etiology of “bruxism” were expressed on dento-dental contacts and on the pathology of muscle contractions. Ideas evolved up to the involvement of behavioral factors and especially of aspects related to sleep (Brocard, 2007). Attanasio R. (1991), Lobbezo and Colab (2006) quoted by Leonardo Lopez do Nascimento and Colab, in 2008, show that nocturnal bruxism etiology involve local, systemic, psychological and hereditary factors. This paper provides a review of the main etiological mechanisms involved in producing and maintaining bruxism

Etiopathogenic grounds responsible for the occurrence of stomatopathy paraprosthetic

Rezumat. Disciplina de Protetică Dentară, Facultatea de Medicină Dentară, U.M.F. Craiova Mucoasa gingivală umană paraprotetică reprezintă o structură cu o morfo-funcţionalitate complexă, integrată sistemului stomatognat. Reabilitarea morfologică şi funcţională a sistemului stomatognat, cu ajutorul protezelor dentare, perturbă echilibrul existent între elementele biotopului oral. Introducerea în cavitatea orală a unui aparat gnatoprotetic are efecte multiple asupra mucosei orale, deoarece piesa protetică reprezintă atât un corp fizico-mecanic, cât şi un amestec chimic. Cercetarile ultimilor ani arată că acţiunile protezelor dentare asupra mucoasei orale sunt influenţate de mediul oral şi sunt atribuite patologiei mediului. Sunt autori care susţin că, în mod practic, nu există mucoasă care să nu reacţioneaze la contactul cu o proteză dentară. Protezele dentare exercită asupra mucoasei orale multiple acţiuni agresive, determinând din partea acesteia o reacţie sau chiar un răspuns pato‑ logic. Mecanismele prin care o proteză dentară traumatizează mucoasa cu care vine în contact sunt diverse. Principalele tipuri de agresiuni ale pieselor protetice dentare asupra mucoasei câmpului protetic sunt: mecanică, termică. toxico-chimică, electrochimică, imunologică şi microbiană.Summary. Paraprosthetic gingival mucosa is a o complex morph-functional structure, integrated in the stomatognathic system. Morphological and functional rehabilitation of stomatognathic system, using dentures, disrupts the existing balance between the elements of oral biotope. Introducing a gnatoprosthetic device in oral cavity has multiple effects on oral mucosa, be cause the prosthetic piece represents both a physical-mecanic body and a chemical mixture. Researches made during last years showed that dentures’ actions on oral mucosa are influenced by oral environment and are attributed to environment’s pathology. Some authors argue that, in practice, each mucosa reacts to contact with a dental prosthesis. Dentures exert multiple aggressive actions on oral mucosa, leading to a reaction or sometimes even to a pathological response. A dental prosthesis traumatizes the mucosa, which comes in contact with, by different mechanisms. The main types of aggressions that prosthetic pieces exert on mucosa of prosthetic field are: mechanic, thermal, toxic-chemical, electrochemical, immunological and microbial

DETERMINATION OF RESISTANCE FORCES FROM MANDIBULAR MOVEMENTS THROUGH DYNAMIC SIMULATION USING KINEMATIC ANALYSIS AND FINITE ELEMENTS METHOD

Aim of the study This study aimed to evaluate the resistance forces that develop in the dental structures of the two left upper premolars during mandibular movements, through dynamic simulation using the kinematic analysis and the finite elements method. Material and methods For this, using several softwares, we obtained a virtual model of the jaw that was attached to a virtual skull. For all the components of the skull and of the dento-maxilar apparatus mechanical properties were given. The movements as mandibule lifting, propulsion, retropulsion and laterality were simulated. Results The study highlighted the presence of resistance forces in the dental structures with values ​​between 31.781 N in the retropulsion movement and 174.104 N in the lateral movement. Conclusions These values ​​are close to the occlusive forces values in the conditions of a balanced occlusion

Etiology Study of Acquired Developmental Defects of Enamel and Their Association with Dental Caries in Children between 3 and 19 Years Old from Dolj County, Romania

Background: Developmental defects of enamel (DDE) are frequently encountered in primary and permanent teeth, yet their etiology is not completely known. Enamel hypoplasia is considered a predisposing factor for early caries. The objective of this study was the evaluation of several risk factors potentially causing DDE and the possible association between DDE and dental caries. Methods: This study was performed on a group of 213 rural children from Romania. It combined a thorough dental examination for all children, and a questionnaire filled in by their mothers, regarding the evolution of their pregnancy and the child’s health status in the first years of life. Results: There was no statistically significant association between DDE presence and data regarding the evolution of pregnancy, mothers’ health status or children’s conditions during early childhood. There was a significant association between the use of amoxicillin, ibuprofen, and cephalosporin during the period of formation of permanent teeth, and one environmental factor (water source), and the presence of DDE (Chi Square, p p = 0.001). Conclusions: Children who consumed water from private wells and children who received medication during early childhood developed more enamel defects, presenting a higher risk of caries development

EFFECTS OF OCCLUSAL LOADS IN THE GENESIS OF NON-CARIOUS CERVICAL LESIONS – A FINITE ELEMENT STUDY

Aim of the study This study investigated the magnitude and distribution of stress in a maxillary first premolar subjected to normal and heavy occlusal loads, that were directed vertically and horizontally, using Finite Element Analysis. Material and methods A virtual 3D model of a maxillary first premolar was created using the CT images of a 14 year-old patient and the physical and mechanical properties of the dental tissues used in other studies. We obtained 8 scenarios for the vertical loading and 8 scenarios for the horizontal loading. Results The magnitude and distribution of stress were the least favorable in the case of the heavy horizontal loading applied on the intact tooth. Conclusions Our study showed that the intact tooth was the most affected by stress regardless of the loading applied

Applications of Optical Coherence Tomography in the Diagnosis of Enamel Defects

Developmental defects of enamel (DDEs) are deviations from the normal appearance in terms of the quantity and quality of tooth enamel. They may be genetic or acquired. The most important DDEs are hypomineralization and hypoplasia. The aim of this study was to produce “in vivo” DDE in Wistar rats by administering amoxicillin to pregnant females and to highlight these lesions after sacrifice of the pups by macroscopic and microscopic examination and optical coherence tomography (OCT). Amoxicillin (100 mg/kg) was administered to two pregnant Wistar female rats for the production of DDEs. When the pups were 2 months old, they were sacrificed, and their jaws were harvested together with their teeth. The jaws were examined macroscopically, microscopically, and by OCT. Following the macroscopic and microscopic examination, it was established that four pups had a total of 42 DDE lesions. At the OCT examination, the hypomineralization was characterized by an intense, inhomogeneous OCT signal, and the hypoplasia was characterized by the absence of the signal. Administration of amoxicillin to pregnant females of Wistar rats resulted in DDEs in their offspring. The OCT examination confirmed the presence of these lesions in the teeth of rat pups

Modifications of the Dental Hard Tissues in the Cervical Area of Occlusally Overloaded Teeth Identified Using Optical Coherence Tomography

Background and objectives: Occlusal overloads produce a series of manifestations in teeth, especially attrition and non-carious cervical lesions (NCCL). Optical Coherence Tomography (OCT) can highlight and evaluate tooth lesions. The aim of this study was to examine the changes of dental hard tissues in the cervical area because of occlusal overload by macroscopic examination and using in vitro Swept Source OCT examination. Materials and Methods: The study was performed on 21 extracted teeth with occlusal trauma. After macroscopic and OCT examination, the 2D OCT images were transformed into 3D images using ImageJ software. Statistical analysis of macroscopic and OCT images was performed with Statistical Package for Social Sciences. Results: On 21 teeth, 88 cervical lesions (cracks) were identified. Upper premolars with an occlusal Smith and Knight tooth wear score of 2 had the most NCCL. Statistical analysis revealed significant differences in the median widths of cervical lesions between teeth with score 1 and score 3. Additionally, we obtained statistically significant differences in median widths between the buccal and oral surfaces. Conclusions: These cracks can be considered precursors of NCCL. NCCL can be located on dental surfaces in the cervical area other than the buccal one. A 3D reconstruction of OCT images emphasized that cracks are located especially at enamel level, evolving towards the enamel–dentin junction, with multiple ramifications

Correlations between Immune Response and Etiopathogenic Factors of Medication-Related Osteonecrosis of the Jaw in Cancer Patients Treated with Zoledronic Acid

Impairment of the immune response in MRONJ (medication-related osteonecrosis of the jaws) is one of the still unclear etiopathogenic mechanisms of this condition encountered in cancer patients treated with bisphosphonates, with negative effects on the patient’s quality of life. The aim of the present study was to correlate the immune response with etiopathogenic factors via immunohistochemical evaluation of the maxillary tissues in zoledronic acid osteonecrosis. The retrospective study included a group of 51 patients with various types of cancers, diagnosed with stage 2 or 3 MRONJ at zoledronic acid and treated surgically. Immunohistochemical expressions of αSMA, CD3, CD4, CD8, CD20, CD79α, CD68, CD204, and tryptase were evaluated. Immunohistochemical markers expressions were statistically analyzed according to the duration of the treatment, the trigger factor, the location of the MRONJ, and the healing status. Analysis of the immune response included T lymphocytes, B lymphocytes, plasma cells, macrophages, and mast cells. The duration of treatment significantly influenced the immunohistochemical expression of most markers (p < 0.05). For an increasing trend in treatment duration, a decreasing trend in marker score was observed, suggesting an inverse correlation. The expression of the markers was different depending on the trigger factor, on MRONJ localization (maxilla/mandible), and the healing status, being more intense in patients cured per primam compared to those who had relapses. The patient’s immune response was negatively influenced by the duration of the treatment, the trigger factor, the location of the lesion in the mandible, and the recurrence of MRONJ

THE NUMBER OF LOST TEETH – A POTENTIAL PREDICTIVE MARKER FOR THE CARDIOVASCULAR DISEASES IN A SAMPLE OF HOSPITALIZED ADULTS

Aim of the study: to evaluate the degree of statistical association between the oral parameter represented by the total number of permanent lost teeth (NLT) on both arches, and a certain type of cardiovascular disease. Materials and methods: 84 hospitalized participants in the Cardiology Department from DrobetaTurnu-Severin County Emergency Clinical Hospital were evaluated in the Emergency Dentistry Department of the same hospital. The demographic and clinical data were collected and statistically analyzed using Chi-square and Kendall’s tau-b, followed by two binomial regression models. Results: A strong, positive association between the NLT and the presence of heart valve diseases, respectively cardiomyopathy was highlighted by Chi-square tests (χ2(2) = 8.774, p = 0.023, respectively χ2(2) = 19.137, p < 0.0005) Also, NLT between 9 and 14 may be considered a statistically significant predictor of developing cardiomyopathy (unadjusted OR = 6.548, 95%CI = 1.764 – 24.304, p < 0.0005), and NLT between 15-27 for developing heart valve diseases (unadjusted OR = 7.886, 95% CI = 1.698 – 36.616, p = 0.008). Conclusions: For the group of participants included in the study, NLT had a statistically significant predictive value especially for heart valve diseases and cardiomyopathy