Heat Treatment's Vital Role: Elevating Orthodontic Mini-Implants for Superior Performance and Longevity-Pilot Study.

Orthodontic mini-implants are devices used for anchorage in various orthodontic treatments. We conducted a pilot study which aimed to observe preliminary trends regarding the impact of heat treatment on the elastic modulus of Ti6Al4V alloy and stainless steel 316L mini-implants. The initial phase involved testing the impact of heat treatment on the mechanical properties of Ti6Al4V alloy and stainless steel 316L mini-implants. MATERIAL AND METHODS: Ten self-drilling mini-implants sourced from two distinct manufacturers (Jeil Medical Corporation® and Leone®) with dimensions of 2.0 mm diameter and 10 mm length were tested. They were separated into two material groups: Ti6Al4V and 316L. Using the CETRUMT-2 microtribometer equipment, indentation testing was conducted employing a diamond-tipped Rockwell penetrator at a constant force of 4.5 N. RESULTS: Slight differences were observed in the elastic modulus of the Ti6Al4V alloy (103.99 GPa) and stainless steel 316L (203.20 GPa) compared to natural bone. The higher elastic moduli of these materials indicate that they are stiffer, which could potentially lead to stress-shielding phenomena and bone resorption. Heat treatment resulted in significant changes in mechanical properties, including elastic modulus reductions of approximately 26.14% for Ti6Al4V and 24.82% for 316L, impacting their performance in orthodontic applications. CONCLUSION: Understanding the effects of heat treatment on these alloys is crucial for optimizing their biomechanical compatibility and longevity in orthodontic treatment. To fully evaluate the effects of heat treatment on mini-implants and to refine their design and efficacy in clinical practice, further research is needed.

The Influence of Orthodontic Treatment on Periodontal Health between Challenge and Synergy: A Narrative Review.

By correctly repositioning teeth, orthodontic therapy improves both the function and appearance of an occlusion. The relationship between teeth and the tissues that surround and support them significantly influences these alterations. With ever more adults seeking orthodontic care, orthodontists are increasingly seeing patients with periodontal issues. Concerns about the patient's appearance, such as uneven gingival margins or functional issues caused by inflammatory periodontal diseases, should be accounted for when designing orthodontic treatment plans. Furthermore, orthodontics may increase the chances of saving and recovering a degraded dentition in cases of severe periodontitis. Today, general dentists, dontists, and orthodontists play integrative roles that enable them to achieve the best possible results for their patients. This review will improve the results of interdisciplinary treatments and increase cooperation between dental specialists by drawing attention to the essential connection between orthodontics and periodontics in regular clinical practice.

An Update on Obstructive Sleep Apnea Syndrome-A Literature Review.

Obstructive sleep apnea syndrome (OSAS) is the most common breathing-related sleep disorder. It is characterized by recurrent episodes of partial or complete airway obstruction during sleep, resulting in a reduction in or the total cessation of airflow, despite ongoing respiratory efforts, leading to oxygen desaturation and arousal. The purpose of this literature review is to evaluate the most common characteristics of this pathology, as well as to investigate the most effective treatment options, providing an update on the management of OSA patients.

A Cross-Sectional, Questionnaire-Based Survey on Air Infection Control among Romanian People.

(1) Background: Infection control should be one of the main objectives in the comprehensive medical approach. (2) Methods: A cross-sectional study was conducted from June-July 2022. A questionnaire including 22 questions with multiple answers was applied online to 202 subjects selected at random. The questionnaire collected data on the subjects' knowledge about protective measures against airborne infections. For this study, a descriptive statistic was performed. Pearson's Chi-square test was used for data comparison. (3) Results: Only 61.39% (124) of the subjects consider that protective equipment is mandatory for the dental team, 40.10% (81) know to a very large extent and 44.06% (89) to a large extent that when talking, a respiratory infection can be transmitted. A rather large percentage of the subjects take into account the cost of the protective mask to a very large extent 39.60% (80). Only 30.20% (61) of the subjects would vaccinate to a very large extent and 24.75% (50) to a large extent against micro-organisms transmitted by air p > 0.05. (4) Conclusions: Most people know the aspects related to air decontamination, the priority being the promotion of control methods of airborne infections, and it is necessary to improve the level of knowledge on a large scale within the population.

Custom-Made Direct Metal Laser Sintering Titanium Subperiosteal Implants in Oral and Maxillofacial Surgery for Severe Bone-Deficient Patients-A Pilot Study.

BACKGROUND: Nowadays, a combination of classical subperiosteal implant designs with 3D imaging and printing allows one to reduce treatment time and provides support for fixed prostheses in cases where other techniques do not provide satisfactory results. This study aims to present a digital technique for the manufacturing of custom-made subperiosteal implants and what complications might appear after this type of surgery. METHODS: Sixteen patients treated with a custom-made DMLS titanium subperiosteal implant during the period between October 2021 and February 2022 were enrolled in the study. Orthopantomography (OPT) and cone-beam computer tomography (CBCT) were recorded for all patients. The measurements taken into account in this study were the fit and stability of implants, duration of surgery, implant survival, and early and late complications. RESULTS: The fit of the implants was extremely satisfactory, with a mean rating of 4 out of 5. The mean duration of the intervention was 86.18 min. At the end of the study, one implant was lost due to insufficient fit and recurrent, untreatable infections. Eleven implants (69%) were placed on the maxillary and five (31%) implants were placed on the mandible. CONCLUSIONS: Taking this into consideration, custom-made DMLS titanium subperiosteal implants could present satisfactory implant survival and low complication rates.

The Link between Obstructive Sleep Apnea Syndrome and Cephalometric Assessment of Upper Airways and Hyoid Bone Position.

Background and Objectives: To determine whether there are changes in the cephalometric characteristics of the upper airways and hyoid bone, in patients diagnosed with obstructive sleep apnea syndrome (OSAS) compared to a healthy control group. Material and Methods: This retrospective case−control study included 24 patients diagnosed with OSAS (apnea−hypopnea index (AHI) > 5 obtained after polysomnography) and 24 healthy subjects as a control group that completed the STOP-Bang questionnaire to determine whether they had OSAS. Lateral cephalometric examinations were recommended for all these patients. The software used for the cephalogram interpretation was CS 3D Imaging and CS Airway imaging from Carestream Dental. Results: The subjects with OSAS had a smaller superior posterior airway space (SPAS), with an average of 10.32 mm compared to a 12.20 mm mean in the control group (p = 0.03). Patients with OSAS, had a lowered middle airway space (MAS) with a mean of 7.96 mm in the OSAS group and a 10.96 mm mean in the control group (p = 0.00). All the measurements made for the hyoid bone, such as­H-MnP, H-C3, and H-B­showed increased values (means of 26.31 mm, 39.08 mm, 60.05 mm, respectively), for the OSAS group (p = 0.00). Conclusions: Patients suffering from OSAS had reduced dimensions of the SPAS and MAS values. The hyoid bone had a more inferior position in the study group (with increased values for H-MnP, H-C3, and H-B) compared to the control group.

A Comparative Analysis of Dental Measurements in Physical and Digital Orthodontic Case Study Models.

Background and Objectives: Study models are essential tools used in the dental teaching process. The aim of the present study was to compare the values obtained by manual and digital orthodontic measurements on physical and digital case study models. Materials and Methods: The physical experimental models were obtained by traditional pouring (improved stone-type IV gypsum products) and by additive manufacturing (resins). The digital experimental models were created by scanning the physical ones, using a white light-emitting diode (LED) source and an L-shaped dental scanner­Swing DOF (DOF, Seoul, Korea). The physical study models were first measured using a digital caliper, and then, they were scanned and evaluated using the DentalCad 3.0 Galway software (exocad GmbH, Darmstadt, Germany). The Pont, Linder−Harth, and Bolton indices, which are used in orthodontics for training students, were derived using the available data. Results: When comparing the linear measurement mean ranks taken on physical study models to those of digital models, no statistically significant differences (p > 0.05) were found. A similar result was also shown when the dentoalveolar growth indicators were analyzed. Conclusions: It can be concluded that dental study models made by direct light processing (DLP) and pouring type IV class gypsum are both acceptable for orthodontic teaching purposes.

The Influence of Gingival Exposure on Smile Attractiveness as Perceived by Dentists and Laypersons.

Background and Objectives: Smile is an important mark of beauty, and smile attractiveness can be influenced by various factors, one of these being the amount of gingival exposure. The aim of this research was to evaluate the perception of an ideal gingival exposure in smile in a sample of Romanian dentists and laypersons, and to find out what is the most important aspect that influences the smile perception for the respondents included in the study sample. Materials and Methods: An online survey was conducted between 3 February 2020 and 31 October 2020. The authors developed a short questionnaire consisting of 7 items. The first four items investigated the respondents' age, gender, profession and whether or not they underwent an orthodontic treatment in the past. For items 5 and 6, participants had to choose the most and the least attractive amount of gingival exposure, and for the last item they had to choose the factor that mostly influences the smile attractiveness in their opinion. Results: 235 questionnaires remained in the study. The sample consisted of 194 women and 41 men, 162 laypersons and 73 dentists. The average value for the most attractive amount of gingival exposure was −0.57 ± 2.407 mm, with a median value of 0 mm while the average value for the least attractive amount of gingival exposure was 1.43 ± 3.785 mm, with a median value of 4 mm. The differences between the most or least attractive gingival exposure perceived by the participants were not significant according to gender or professional category (p > 0.05), but, when compared between having or not having an orthodontic treatment in the past the differences were statistically significant (p < 0.05). As such, participants who had an orthodontic treatment in the past perceived a significantly higher value for the most attractive gingival exposure, and a significantly higher value for the least attractive gingival exposure (p = 0.026) than the participants who didn't have an orthodontic treatment in the past. As for the factor that mainly influences smile attractiveness, laypersons chose significantly more frequent white teeth or aligned teeth (96%, 71.7%) while dentists chose significantly more frequent a gingival exposure between 0−3 mm (70.4%) as smile factors for an aesthetic smile (p < 0.001). Conclusions: In this study sample, the respondents considered that the most attractive smile involved a covering of 0.57 mm (in average) of the upper incisors by the upper lip. Although smile attractiveness did not appear to be influenced by gender or profession in this study population, it was influenced by previous orthodontic treatment. The participants' roles of dentist or layperson influenced the factors chosen for an aesthetic smile.

Extra-Oral Three-Dimensional (3D) Scanning Evaluation of Three Different Impression Materials-An In Vitro Study.

Impression materials are used to record and reproduce the exact morphology of the patient's oral cavity. The dimensional stability of a material is its ability to maintain the accuracy of recording the details of the oral cavity for a longer period of time, including the time during imprinting and immediately after. The aim of this study was to evaluate the accuracy of three different impression materials commonly used in the dental practice with the aid of an extra-oral three-dimensional (3D) scanner using an in vitro analysis. A typodont tooth model of the maxillary dental arch and mandibular dental arch, containing 16 permanent teeth, was used for evaluation. With the aid of three different impression materials, this model was imprinted fifteen times, resulting in fifteen different plaster models. A capsule extra-oral scanner device was used to digitalize the models and the same device was later used to align, compare, and measure scanned model surfaces. After performing the Kruskal-Wallis test for each measurement category (model), only two out of the fifteen measurements showed statistically significant differences between the material groups: vestibular-oral and mesial-distal width. Post hoc analysis showed that the alginate model (mean range = 29.13) had significantly higher bias scores than the addition silicone model (mean range = 16.75) (z = 2.501, p = 0.037). The difference between the average values of the model bias made from condensation-based silicone and addition-based silicone was initially significant, but after applying the Bonferroni correction for further comparisons, this relationship did not remain significant (z = 2.197, p = 0.084). Addition-based silicone models had the highest accuracy in terms of fidelity, followed by condensation-based silicones, and then by alginate models. Silicone-based impression materials improved over time, being highly used in all areas of dentistry. Alginate impressions had the lowest pattern of accuracy among those studied.

uNGAL Predictive Value for Serum Creatinine Decrease in Critically Ill Children.

Acute kidney injury (AKI) occurs frequently in critically ill children, having an incidence of up to 26.9% and is associated with high morbidity and mortality in pediatric intensive care units (PICU). Currently, the decrease in the glomerular filtration rate is calculated using the serum creatinine levels. Nevertheless, there may be a 48 h delay between the renal injury and measurable increase in creatinine. Urinary neutrophil gelatinase-associated lipocalin (uNGAL) has been validated in relation to cardiopulmonary bypass in children, being able to detect AKI before the functional change proven by the rise in serum creatinine. Our aim was to study the utility of using uNGAL in the management of critical pediatric patients admitted to our hospital in a six month period, more specifically, its capacity to predict AKI development, alone and in the association with the renal angina index (RAI). Twenty-eight critically ill children aged from 1 day to 15 years have been included. We found that an increase in uNGAL in day 1 of admission in the PICU was significantly correlated with a decrease in creatinine clearance but not anymore in day 3. However, in our sample uNGAL did not show a significant predictability for AKI development nor the supplementary incorporation of RAI into the prediction model. Therefore, apart from cardiac surgery, the efficacy and utility or uNGAL in the management of critically ill children is still questionable. For the best prediction, we will need to incorporate not only the RAI or other PICU scores, but other biomarkers such as KIM-1, urinary cystatin, and IL 18 in larger samples.

Substantial Improvements in Facial Morphology through Surgical-Orthodontic Treatment: A Case Report and Literature Review.

Background and Objectives: The long face type is associated with excessive vertical facial growth and most often with anterior open bite. In many cases of anterior open bite of high severity associated with bimaxillary dento-alveolar protrusion, lips are unable to form an adequate seal at rest. This leads to many issues, including facial dysmorphism. The aim of this study was to describe the case of a 15 year old girl who addressed the orthodontist in November 2015, having complaints related to the skeletal and dental open bite. Case Description: A 15.7 year old patient required a consultation with the orthodontic service for impaired dento-facial aesthetics at rest, smile and speech due to an exaggerated superior protrusion of the upper frontal teeth, labial incompetence with excessive gingival exposure at rest and smile associated with upper and lower anterior teeth crowding. The orthodontic diagnostic consisted of skeletal open bite with a hyperleptoprosop morphological facial type, high degree of hyperdivergence, bimaxillary dento-alveolar protrusion, 7 mm skeletal open-bite, 3 mm vertical inocclusion of the anterior teeth, skeletal class II relationships, bilateral half cusp class II molar and canine relationships, labial incompetence, highly increased interlabial gap, facial asymmetry, excessive gingival exposure of 7 mm at smiling and bimaxillary anterior crowding. Because the patient initially refused orthognathic surgery, prior to starting the orthodontic treatment, the patient was recommended to receive a bilateral extraction of the first upper premolars. Key objectives of pre-surgical orthodontic treatment were to achieve a retroclined position of the upper incisors under their normal inclination for the planned upward maxillary rotation, to maintain slightly lower incisor proclination. The orthognathic surgery consisted of Le Fort I impaction osteotomy with 8 mm anterior impactation, bilateral sagittal split osteotomy, and mandibular repositioning using occlusal splint. Conclusions: At the end of the orthodontic-surgical treatment, the patient presented significant improvement in dento-facial aesthetics, and optimal skeletal, muscular and dental balance.

Acute Otitis Media in Children-Challenges of Antibiotic Resistance in the Post-Vaccination Era.

Acute otitis media (AOM) is a leading cause of antibiotic prescriptions in children worldwide, even in the era of pneumococcal conjugate vaccines. We aimed to assess the bacterial spectrum of AOM in children and to investigate the antimicrobial resistance profile in culture-positive cases. We performed a retrospective, tympanocentesis-based analysis of antimicrobial resistance patterns in children with AOM hospitalized in "St Mary" Emergency Hospital for Children Iasi, Romania, between January 2013 and December 2021. A total of 147 samples have been assessed, 97 (65.98%) of which had positive cultures, with Streptococcus pneumoniae and Haemophilus influenzae as the most common microorganisms. A worrying proportion, 82.85% (58/70), of the Streptococcus pneumoniae strains were multidrug-resistant. The World Health Organization included Streptococcus pneumoniae and Haemophilus influenzae on the medium priority group due to penicillin non-susceptibility and ampicillin-resistant strains, respectively. Consequently, strategies to address the threats of antimicrobial resistance are needed to reduce the potential negative effects on hospitalization costs.

Nicotine Exerts Cytotoxic Effects in a Panel of Healthy Cell Lines and Strong Irritating Potential on Blood Vessels.

The use of tobacco products is a major global public health issue, as it is the leading cause of preventable death worldwide. In addition, nicotine (NIC) is a key component of electronic and conventional cigarettes. Although nicotine's addictive potential is well known, its health effects are not entirely understood. Thus, the main objective of the present study was to evaluate its toxicological profile both in vitro, at the level of three healthy cell lines, and in ovo, at the level of the chorioallantoic membrane. Five different concentrations of nicotine were used in keratinocytes, cardiomyocytes, and hepatocytes for the purpose of evaluating cell viability, cell morphology, and its impact on nuclei. Additionally, the hen's egg test on the chorioallantoic membrane (HET-CAM) method was used to assess the biocompatibility and irritant potential of the chorioallantoic membrane. Across all cell lines studied, nicotine was proven to be significantly damaging to cell viability, with the highest concentration tested resulting in less than 2% viable cells. Moreover, the morphology of cells changed dramatically, with alterations in their shape and confluence. Nicotine-induced cell death appears to be apoptotic, based on its impact on the nucleus. In addition, nicotine was also found to have a very strong irritating effect on the chorioallantoic membrane. In conclusion, nicotine has an extremely strong toxicological profile, as demonstrated by the drastic reduction of cell viability and the induction of morphological changes and nuclear alterations associated with cellular apoptosis. Additionally, the HET-CAM method led to the observation of a strong irritating effect associated with nicotine.

Knowledge, Practice, and Awareness of Oral Cancer and HPV Infection among Dental Students and Residents: A Cross-Sectional Study.

Background and Objectives: Dentists play a very important part in the early identification of oral cancer lesions. This aspect of dental practice depends on the knowledge acquired during the faculty years. The aim of this study was to assess dental students' and residents' levels of awareness in terms of oral cancer. Materials and Methods: The cross-sectional study was conducted at the Faculty of Dental Medicine within the "Grigore T. Popa" University of Medicine and Pharmacy in Iasi, on a sample of 197 students in the fourth and the fifth years and first year residents in general dentistry. To assess their knowledge, a questionnaire was created containing 22 questions about the risk factors for oral cancer, with a focus on HPV infection. Results: Most participants correctly identified smoking, alcohol, and the HPV infection as risk factors and leukoplakia and erythroplasia as potentially malignant lesions. At the opposite site, aspects considered as unsatisfactory focused on the palpation of lymphatic nodules, a procedure largely carried out by 41.6% of the fourth year students, the counseling only of the patients at risk performed by 59.7% of residents, the lack of knowledge about the prevention of oral cancer through anti-HPV immunization found in 39.7% of the fifth year students. Other incorrect answers focused on other types of suspicious lesions, such as actinic cheilitis, as well as certain areas in the oral cavity subject to the frequent onset of oral cancer, such as buccal mucosa. Conclusions: Although the fifth year students and residents have better knowledge than the fourth year students, the gaps in terms of knowledge and practice encountered in all three categories of participants require a reevaluation of the academic curriculum and the focus on the building of the skills necessary for the correct screening of oral cancer.

Radiographic methods for locating impacted maxillary canines.

Maxillary canine impaction is a fairly common phenomenon in dental practice. Most studies indicate its palatal position. For a successful orthodontic and∕or surgical therapy, it is necessary to correctly identify the impacted canine in the depth of the maxillary bone, using conventional and digital radiological investigations, each with their advantages and disadvantages. Dental practitioners must indicate the most "targeted" radiological investigation. This paper aims to review the various radiographic techniques available for determining the location of the impacted maxillary canine.

Pointing on the early stages of maxillary bone and tooth development - histological findings.

Although the morphological stages of tooth development, in parallel with maxillary bone construction, are known for decades, the intimate mechanisms of early development of the oral cavity structures and tooth's proper and associated tissues are still incompletely elucidated. Nowadays, the research in embryology was shifted from the morphological to the molecular and genetic approach. This new approach is accomplished by using in vivo and in vitro experimental studies performed on animal models and cell lines. The interest in the knowledge of these events at gene and molecular level is still current, aiming to sustain the progress in the endorsement of novel regenerative and restorative therapies. However, the morphological standpoint maintains its interest, because the extrapolation of the results of experimental studies in humans requires a strong confirmation. Within this context, our work aims to analyze the histological characteristics of the maxillary bone and integrated tooth germs during the early stages of embryonic development. The study group consisted in mandible fragments obtained by dissection of the cephalic extremities collected from fetuses aged from 10 to 24 weeks, after medical or spontaneous abortions. The tissue specimens were processed for the histological exam. The histoarchitectonic traits of the initial stages of mandibular bone tissue and tooth development were assessed. The results revealed the dynamics of the ossification stages, from stages of early-dispersed intramembranous ossification to the organization of the dental alveoli, incorporated step-by-step in the maxillary body, and the simultaneous presence of tooth germs with different sizes and shapes, in accordance with the development stage. Our study complements the existing data regarding the embryonic period, bringing an important contribution for the enlargement of existing morphological, visual information for maxillary bone and tooth development.

AXIAL MODIFICATIONS OF PERMANENT LOWER MOLARS AFTER PREMATURE LOSSES OF TEMPORARY MOLARS.

AIM: The aim of our study was to determine the impact of premature loss of temporary lower molars upon the longitudinal axis of the first and second permanent molars. MATERIAL AND METHODS: The study groups included 61 patients, 6-9 year olds with premature loss of primary molars and a control group of 24 patients with intact temporary teeth. We evaluated the angle between longitudinal axis of first and second lower permanent molars and occlusal plane. RESULTS: It was observed that premature loss of lower second deciduous molar modifies more the vertical axis of first and second permanent molars than the premature loss of first lower primary molar. Reducing space occurs mainly through mesial inclination of molars that separates the edentulous breach. Temporary loss of both lower first molars on the same quadrant causes an accelerated eruption of both premolars increasing the prevalence of eruption sequence: "4-5-3-7". CONCLUSIONS: The preservation of the occlusal morpho-functional complex using space maintainers mainly when the premature loss of the second primary molars occurs is the best interceptive treatment option.

Evaluation of the Influence of Local Administration of Vitamin D on the Rate of Orthodontic Tooth Movement.

Accelerated orthodontic tooth movement is currently the subject of numerous scientific studies that aimed to improve the duration of orthodontic treatment. Several approaches had been performed in order to reduce the period in which a patient is subjected to orthodontic treatment. This are biological, surgical and physical approaches. Aim: This study has two purposes: first to assess the influence of local administration of vitamin D3 on orthodontic tooth movement and second to evaluate if there is any secondary effect of locally administration of vitamin D3 on dental roots. Material and methods: Every dental arch has been divided in two: one control quadrant and one experimental quadrant. The control canine received only conventional orthodontic treatment in comparison with the experimental canine who benefited from the association between orthodontic therapy and intraligamentary administration of vitamin D3. Results: 6 dental arches were studied. The average rate of tooth movement was greater in experimental canines compared to control canines. We recorded an average of 70 % more tooth movement for the experimental teeth compared to control ones. The differences between the two quadrants (control and experimental) are statistically significant. Conclusions: Locally administration of vitamin D3 seemed to increase the rate of orthodontic tooth movement. No root resorption was found three months after the first administration of vitamin D3 evaluated on cone-beam CT exam (cone-beam computed tomography).

Assessment of orthodontic biomaterials' cytotoxicity: an in vitro study on cell culture.

OBJECTIVE: Orthodontists use various biomaterials such as molar bands, brackets, archwires, transpalatal archwires, facial masks and other auxiliary devices. One of the essential properties of these materials should be the biocompatibility. The aim of this study was to evaluate the biocompatibility of some orthodontic biomaterials like stainless steel archwires, brackets and NiTi (nickel-titanium alloy) coil springs. MATERIALS AND METHODS: The studies were performed in vitro using human fibroblasts cultures on which the orthodontic materials were applied. The positive control was the copper amalgam. Readings of the cell reactions were performed at three and six days. RESULTS: It was observed that the materials used in the study cause cell alterations of variable intensity. The metallic brackets represent an important cell stress factor causing shape changes. For the metallic brackets, a preferential tropism for different areas of the bracket was also obvious. We observed a preferential tropism for the areas between the NiTi coil spring spirals. For the stainless steel archwires, we observed at six days a decay of cell density and also a higher amount of cells near the archwire areas on which bends were performed. CONCLUSIONS: All biomaterials analyzed in our study cause cellular changes of varying intensity without necessarily showing a cytotoxic character.

The influence of premature loss of temporary upper molars on permanent molars.

AIM: Premature loss of primary molars due to dental caries and their complications has been associated with space loss and eruptive difficulties, especially when the loss occurs early. The aim of our study was to determine the impact of premature loss of temporary upper molars upon the longitudinal axis of the first and second upper permanent molar. MATERIAL AND METHODS: The study group included 64 patients 6-9 years old with premature loss of primary molars and a control group of 48 patients with intact temporary teeth. It was evaluated the angle between longitudinal axis of first and second upper permanent molars and occlusal plane. The sofware used is Easy Dent 4 Viewer®.The data were analyzed by using the Statistical Package for the Social Sciences (version 20.0; SPSS, Chicago, III). RESULTS: It was observed that premature loss of upper second deciduous molars modifies greater the vertical axis of the permanent molars than the premature loss of first upper primary molar. First upper primary molar loss cause an acceleration eruption of first premolar, which will produce a distal inclintion of the both permanent molars. CONCLUSIONS: The use of space maintainers after premature loss of the second upper temporary molar is a last solution in preventing tridimensional lesions in the dental arch and occlusion.