Introduction:The influence of mouth breathing on the development of the dentition and dento-facial deformities is a problem causes concerns among the medical specialists. Mouth breathing has a major impact on the development of the maxillo-facial region, occlusion and muscle tonus.Aim: The aim of this study is to assess the relationship between etiological factors, pathogenesis and disturbances in mastication in mouth breathing patients.Material and methods: For this article, data is obtained from 43 medical, literary sources.Results: Literature review demonstrated that mouth breathing habit affects mostly children aged 7 -12 years. In the vast majority of studies, the authors established a relation between mouth breathing and the development of maxillo-facial region and occlusion. The malocclusions described include a distal occlusion, anterior open bite, increase overjet, posterior crossbite, crowding and average incisors inclination disturbances. These clinical conditions become more complicated in the late-mixed and permanent dentition if mouth breathing continues to persist. Conclusion:The habitual mouth breathing is a great medical problem nowadays. An increasing numbers of patients with this condition although the development of technology for early diagnostic is embarrassing. This condition is strongly related with different malocclusions such as anterior open bite, overjet, distal occlusion, underdeveloped and narrow upper jaw, increased anterior facial height.

Development of the dental arches and occlusion in permanent dentition can be divided into several stages and has to be observed regularly. The first permanent molar eruption is related to the onset of significant changes in the developing occlusion. Although this tooth is seen as the "key to occlusion" its value as an anchorage is debatable. The aim of the article is to study the correct position of the upper first molars in the two planes of spacethe sagittal and transverse planes. In this article the position of the first upper molar is examined with the aid of diagnostic records, such as study cast, orthopantomogram (OPG), and lateral cephalometrics. A literature review includes Bulgarian and foreigner authors. Angle, who in 1899 referred to the maxillary first permanent molars as the "key to occlusion", was the first to mention their importance within the dentition. According to Angle, the line passing through the middle of the mesiobuccal cusp of the upper first molar coincides with the line passing through the buccal groove of the lower first molar. After Angle, other authors have discussed the position of upper molars from different point of view, such as their relation or position in the maxilla, anteroposterior axial inclination and rotation. As indicated by Lamons and Holmes molar rotations commonly exist in Class II malocclusions. The molars are usually rotated around an axis lingual to their central fossae. In an ideal occlusion the buccal surfaces of the upper first molars are usually parallel to each other On the OPG Kurol and Bjerklin measured the axial mesial inclination of upper first molar. The tipping of the molars is measured by the angle formed between the tangent line to the mesial surfaces of the root and crown and the line through the lower margins of the left and right orbits. According to Sassouni, the mesial contour of upper first molar should to lie on the 4th arc-the temporal arc. If the molar is anterior to this arc, a treatment with distalization could be initiated. The temporal arcnasion distance measured on the radius is equal to the distance from point ANS to the upper first molar. The position of the upper first molar varies with the position of the upper central incisors. The basic hypothesis is that if the upper first molar has a fixed position in the face, any increase in the total upper dental arch length will be transferred to the incisor area. Any change in the anteroposterior position of the upper first molar could influence the position of the mandibular-leading to Class II malocclusion. Ricketts pointed out that the average distance from the pterygoid vertical (PTV) to the distal surface of upper first molar is the sum of the age of the patient The Importance of Upper First Permanent Molars Position for the Orthognatic Occlusion

Introduction: Difficult nasal breathing is a common problem, which may be a result of multiple factors, leading to physiological disturbance and/or anatomical disorders of the nose and paranasal sinuses. One of the most frequent reasons in childhood age is adenoid hypertrophy. Aim: The aim of the current article is to determine the influence of adenotomy and adenoidectomy on the respiration and occlusion of children with difficult nasal breathing Materials and Methods: A total of 412 children, diagnosed with difficult nasal breathing, took part in the study. Of them, 139 underwent a second clinical examination in the period of 1 to 3 months to determine the way of breathing after adenotomy/adenoidectomy.Results: In primary dentition, after removing the etiological factor for difficult nasal breathing, 68.00% of the children began to breathe spontaneously through the nose. In mixed dentition, there was a higher percentage of children, who maintained mouth breathing as a bad habit. In comparison to the dental class after adenotomy/adenectomy, there was a higher percentage of Angle class II. In the saggital plane there was an

Introduction: A literature review established that the number of mouth-breathing children varies between 5-75%. Girls are more often diagnosed with this condition compared to the boys. In the 19 th century Linder-Aronson established the relationship between mouthbreathing and malocclusions. The recognition of the mouth-breathing pattern and the habitual mouth breathing as factors in developing malocclusions requires prophylaxis and timely treatment. Aim: The purpose of this study is to establish the incidence and type of malocclusions among mouthbreathing children with primary and mixed dentition. Materials and Methods: A total of 412 children diagnosed with mouth breathing and 317 children diagnosed with habitual mouth breathing aged 3-12 years were examined. The dental occlusion of every child was assessed in the three planes of space-sagittal, transverse and horizontal in both segments-frontal and buccal. Results: In both groups a statistically significant difference in dental malocclusions was demonstrated (p<0.001) depending on type of dentition. In both groups the vast majority of children were diagnosed with class II Angle malocclusion in both primary and mixed dentition. The children with primary dentition were more often diagnosed with class I Angle malocclusion. Conclusion: In both groups the most frequent malocclusions present were class II Angle, overjet, bilateral posterior crossbite, open bite within 3 mm in the fron

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