Linear and volumetric analysis of condylar morphology in adults: a cone-beam computed tomography study

Department of prosthetic dentistry ‘Ilarion Postolachi’Introduction. The study of anthropometric data has always been of great scientific interest. In the clinic of orthopedic dentistry, anthropometric diagnostic methods are widely used, initially proposed by Garson (1910), Williams (1913), Gofung (1938), Martin (1957), Kurlyandsky (1958) and others. One of the most important parts of the dento-maxillary system is the temporomandibular joint (TMJ). Determination of linear and volumetric parameters of the TMJ constituent elements on a patient during a clinical examination is difficult due to objective reasons. The difficulty in studying the structural organization, function and diagnosis of TMJ diseases is explained by its small size, different density of constituent elements, localization near the base of the skull, late manifestation of clinical and diagnostic signs of dysfunction with a long latency period. At the same time, the development of X-ray examination methods, particularly CBCT, makes it possible to study these parameters with high accuracy. Data on the average parameters of the TMJ can be used to draw the line between norm and pathology in the course of complex patient treatment. The attention of the authors of the present study was drawn to the bone structures of the temporomandibular joint, namely to the linear and volumetric parameters of the mandibular condyle (CM), as the most stable element of the TMJ. The depth of the glenoid fossa, the inclination of the articular tubercle are strongly dependent on the strength and direction of the chewing pressure, they change significantly with the loss of teeth. The CM is also exposed to these changes, but at the same time its shape, volume, longitudinal and transverse dimensions are relatively constant. (Kulakov A., Robustova T., 2015). Aim of the study. The purpose of the study was to analyze the available literature and to determine linear and volumetric parameters of the CM in adults using cone-beam computed tomography (CBCT). Material and methods. Using the search engines Pubmed, Springer, Google Scholar were selected scientific articles dedicated to the study of TMJ using CBCT. The original study was carried out on the basis of 41 CBCT in patients aged 25 to 58 years, without TMJ pathology. The study consisted in measuring the linear and volumetric parameters of 82 mandibular condyles. All CBCTs were performed in specialized radiological centers in Chisinau in diagnostic purpose of dental treatment, so none of the patients was exposed to an additional dose of radiation. Patients with age less than 25 years, with presence of any craniofacial anomalies or syndromes, and as well TMJ dysfunction were excluded from the study group. Measurements and statistical processing were performed using Slicer 3D and Microsoft Excel software. The study of CBCT and the determination of the quantitative values of the parameters of interest were carried out in the Slicer 3D version 4.11 according to the conventional method [2]: 1) Automatic segmentation of a 3D model of the lower jaw with manual correction and smoothing - Fig. 1; 2) Manual determination of the cephalometric landmarks Porion and Orbitale, which determine the Frankfurt plane for the right and left side; 3) Manual determination of the cranial, medial and distal poles of the left and right condyle - the most distant points in the corresponding directions. 4) Manual determination of the caudal point of the sigmoid notch (InfSig) for the right and left side – Fig. 2; 5) Separation of the condyle volume by a plane parallel to the Frankfurt plane passing through the caudal point of the sigmoid notch - Fig. 3; 6) Automatic calculation of the height, width and volume of the CM with the built-in tools of the Slicer 3D program - Fig. 3, 4. Results and discussions. The research results are presented in tables №1 and №2. The mean CM volume in the study group - 1759 ± 88.7 mm3, the CM height - 18.65 ± 0.54 mm, and the CM width - 19.79 ± 0.45 mm (95% confidence interval). The obtained results are close to the values of the other authors studies. According to Santander, P. et al., 2020 [1], the width of CM is 19,5 mm on average, and the height is 17,3 mm. At the same time, the authors note the largest size of the condyle in skeletal class III. In the work of Mendoza, L.V., (2018) [2] the measured mean CM volume for the right and left sides was 1932.7 and 1881.6 mm3, respectively. The difference in volume between the right and left condyle in the same patients averaged 7.78±1.95%, ranging from 0 to 25%. Such differences can be explained on the basis of the asymmetry seen in all structures of the body. In the work of Tecco, S. (2010) [3] the difference in volume between the right and left sides averaged 3.9%, and the difference in the condyle surface was 5.45%. When using the obtained data in clinical practice, many factors must be taken into account. The results of the study depend on the measurement technique, the size of the CBCT voxel, the contrast possibilities of the CT scanner, the degree of calcification of the bone structures, the accuracy of the operator's manual segmentation, ethnic and racial differences in the study group. Conclusions. A complete 3D analysis of the morphology of the mandibular condyle emphasizes its versatility. In the assessment of symmetries between the condyles, they are asymmetrical and therefore each condyle must be evaluated separately. The volume, size and position of the condyle can be an important indicator of TMJ disease. To identify the relationship between linear and volumetric parameters of the condyle and TMJ dysfunction, further study of functionally healthy joints is necessary in order to obtain stable and repeatable data

Analiza liniară și volumetrică a morfologiei condilului mandibular la adulți cu utilizarea tomografiei computerizate

Catedra de stomatologie ortopedică „Ilarion Postolachi”, USMF „Nicolae Testemiţanu”Background. Determination of linear and volumetric parameters of the mandibular condyle (CM) in normal and pathological conditions is one of the relevant issues of modern dentistry, considering the importance of the condyle in TMJ and the entire dentoalveolar system functioning. Objective of the study. The purpose of the study was to analyze the available literature and to determine linear and volumetric parameters of the CM in adults using computed tomography (CT). Material and Methods. The analysis of the literature was performed, in number of 14 scientific papers (2007 – 2021). In present study, the volumetric and linear parameters of 82 CM were studied using CBCT in 41 people aged 25- 58 years without TMJ pathologies and signs of CM atrophy. Measurements and statistical processing were performed using Slicer 3D and Microsoft Excel software. Results. The mean CM volume in the study group - 1759 ± 88.7 mm3, the CM height - 18.65 ± 0.54 mm, and the CM width - 19.79 ± 0.45 mm (95% confidence interval), which corresponds to the data of Mendoza et al, 2018; Santander et al, 2020. The difference in volume between the right and left condyle for the same pacients averaged 7.78 ± 1.95%, ranging from 0 to 25%. Conclusion. The results partially confirm the literature data. Discrepancies are explained by the use of different measurement methods, as well as the incongruity of the study groups. The comparison of the right and left CM volume was not found in the literature, being an original information.Introducere. Determinarea parametrilor liniari și volumetrici ai condilului mandibular (CM), în condiții normale și patologice, este una dintre problemele actuale ale stomatologiei moderne, având în vedere importanța lor în funcționarea ATM și a întregului sistem stomatognat. Scopul lucrării. Analiza datelor literaturii și studierea parametrilor liniari și volumetrici ai CM la adulți, utilizând tomografia computerizată (CT). Material și Metode. A fost efectuată analiza literaturii pe tema cercetării, în număr de 14 lucrări științifice (2007 – 2021). În studiul prezent au fost analizaţi parametrii volumetrici și liniari ai 82 de CM pe CT la 41 de persoane, cu vârste între 25 și 58 de ani, fără patologii de ATM. Măsurările și prelucrarea statistică au fost efectuate cu utilizarea Slicer 3D și Microsoft Excel. Rezultate. Volumul mediu al CM în lotul de studiu - 1759 ± 88,7 mm3, înălțimea CM - 18,65 ± 0,54 mm și lățimea CM - 19,79 ± 0,45 mm (interval de încredere 95%), ceea ce corespunde datelor lui Mendoza et alia, 2018; Santander et alia, 2020. Diferența de volum între CM drept și stâng, la aceeași pacienți, a fost în medie de 7,78 ± 1,95%, variind de la 0 la 25%. Concluzii. Rezultatele studiului propriu parțial corespund datelor literaturii. Diferențele în volumul mediu al CM se datorează metodelor de măsurare diferite și incongruenței loturilor de studiu. Comparația volumului CM drept și stâng nu a fost idetificată în literatura, fiind o informație originală

State of glutathione reductase – glucose-6-phosphate dehydro-genase system in saliva of students from different countries

Nicolae Testemitanu State University of Medicine and Pharmacy, Chisinau, Republic of Moldova, The 6th International Medical Congress for Students and Young Doctors, May 12-14, 2016Introduction. Reduced glutathione performs a protective antitoxic and antioxidant role. The only enzyme, whose basic biological significance to maintain a high level of reduced glutathi-one is glutathione reductase. Normal functioning of glutathione requires coenzyme NADPH, which generates aerobic glucose oxidation pathway (pentose phosphate pathway) through the action of glucose-6- phosphate dehydrogenase. The amount of glutathione varies, so a patholog-ical insufficiency of it was observed at a third of the population. Genetic and biochemical stud-ies have demonstrated the important role of glutathione and glutathione-dependent enzymes, which control the intracellular redox-state, inactivate oxygen radicals, protect from oxidative stress. Purpose. Comparative analysis of the glutathione reductase – glucose-6-phosphate dehydrogenase state in saliva of students from different countries. Material and methods. The study involved 46 healthy students (20-23 years): Moldova (group 1), Israel (group 2), Palestine (group 3), Congo (group 4). The study complied with all ethical and legal norms. The activity of glutathione reductase (GR), glucose-6-phosphate dehydrogen-ase (G6PD), content of reduced glutathione (RG) and protein were determined by spectropho-tometry (DiaSys). Statistics: t-Student and Spearman. Results. The content of RG in the saliva of 2nd group was 33,49 mcmol/g protein (185,6%; p<0.01), in the 3rd – 10,1 mcmol/g (56%) and in the 4th – 40,30 mcmol/g (223,4%; p<0,001) compared with the 1st group (18,04 mcmol/g, 100%). Activity of GR in the saliva of 1st group was 12,0 IU (100%), in the 2nd group - 20,6 IU (171,7%), in the 3rd – 38,3 IU (319,2%), in the 4th group - 29,1 IU (242,5%). Activity of G6PD in the 1st group was 6,6 IU/l (100%), in the 2nd – 18,7 IU/l (283,3%), in the 3rd – 8,9 IU/l (134,8%), in the 4th group - 13,1 IU/l (198,5%). The results of Spearman's rank correlation analysis showed a close relationship between GR and G6PD in 1st, 2nd and 4th groups. However, the functional relationship between the GR and RG was only found in the third group (Pt <0,0025). Conclusion: The differences between the content of GR and level of G6PD activity in the saliva of the students from different countries likely reflect the genetically determined metabolic features. Correlation analysis using the nonparametric Spearman test showed functional rela-tively close relationship between all the parameters considered, which may indicate modifica-tions of metabolic processes in the growing organism

CAD/CAM in modern orthopedic dentistry

Department of Orthopedic Dentistry, Nicolae Testemitanu State University of Medicine and Pharmacy of the Republic of MoldovaIntroduction. CAD/CAM (Computer - aided Design, Computer - aided manufacturing) is a perspective branch of digital dentistry. The whole СAD/CAM technological process from taking impressions until fixation is performed by chairside and can take only one visit. According to polls (2016), 89% of dentists consider that CAD/CAM technology has to replace conventional process of modelling and manufacturing of prosthetic constructions in the nearest future. Aim of the study. to analyze technological possibilities of СAD/CAM in orthopedic dentistry, to reveal advantages and disadvantages of CAD/CAM technology on the example of a clinical case. Materials and methods. Was carried out a review of the publications of the last 10 years on the selected theme using PubMed system. According to a key phrase "CAD/CAM" 1862 publications were found, 80 publications were selected and analyzed. Research includes data from 20 publications. Examination of a patient at the age of 32 years with partial defect of solid tissues of lateral teeth of the maxilla was performed. Defect was treated with the help of zirconium crowns manufactured by means of CAD/CAM technology. Results.The analysis of literature allowed to define the main advantages of CAD/CAM technology: 1) accuracy of marginal fit and occlusal contacts; 2) high esthetics; 3) concept of one-visit dentistry; 4) decrease of human factor; 5) stability and predictability of treatment. Presented clinical case confirms mentioned advantages of CAD/CAM technology. According to five sources, marginal discrepancy of the CAD/CAM crowns varies from 30 to 60 microns. At the same time traditional full ceramic crowns have an average discrepancy 90 microns. Researches demonstrate maintaining of 95-98% of CAD/CAM crowns for the 6-year period of clinical observation (R. Van Noort, 2012, M. Fages, 2017, Alqahtani, 2017). The analysis of literature revealed fact that rather small significance is attached to applying of CAD/CAM digital workflow in treatment of handicapped people and other categories. Possibility to minimize the number of visits for this group of patients is the greatest advantage. Were defined the following shortcomings of CAD/CAM technology: 1) high cost; 2) increased material consumption; 3) limitations in several types of prosthetic constructions. Conclusions. 1. The analysis of literature showed that CAD/CAM the technology has large prospects in modern dentistry due to constant perfecting. 2. The quality of CAD/CAM crowns and bridges surpasses the quality of conventional constructions of the same type. However, partial and complete CAD/CAM dentures, as well as some other constructions, still have lack of precision

Anatomy of the Mandible: Developmental Variations and Clinical Significance

Introduction: Anatomical structures serve as landmarks for dental procedures. Therefore, in our present study, we determined the most common anatomical variations of mandibles. Material and Methods: The study included 50 dry mandibles from the department of human anatomy obtained from patients of Moldavian origin. The obtained data was analysed using descriptive statistics and Pearsons correlation. A p level of less than 0.05 was considered to be statistically significant. Results: The mandibular foramen was situated in the inferior 1/3 of mandibular ramus in 30 cases (60%). In 20 cases (40%) the mandibular foramen was situated in the middle of the ramus. Both premolar foramen and accessory mandibular foramen was encountered in two cases respectively (4%). Mylohyoid bridging was also encountered in two cases (4%). The condylar morphology differed according to its surface and was classified into four types: type A - superior surface flattened, type B - superior surface convex, type C - superior surface angled and type D - superior surface rounded. The morphology of the left condylar process according to the types: A – 20 cases (40%), B – 16 cases (32%), C – 2 (4%), D – 12 (24%). The morphology of the right condylar process according to the types: A – 16 cases (32%), B – 20 (40%), C – 6 (12%), D – 8 (16%). There were four common forms of the lingula: triangular lingula (type 1), truncated lingula (type 2), lingula seen as a less prominent nodule (type 3), lingula assimilated in the mandibular ramus (type 4). The lingual type from the right side: type 1 – 8 (16%), type 2 – 18 (36%), type 3 – 18 (36%) and type 4 – 6 (12%). The lingual type from the left side: type 1 – 10 (20%), type 2 – 18 (36%), type 3 – 18 (36%) and type 4 – 6 (12%). Conclusions: The anatomy of the mandible has several clinically significant anatomical variations, which should be taken into consideration in daily dentist practice. The data provided in the article discusses some of the variations of the development and morphological parameters of mandibles from the Moldavian population