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MINISTRY OF EDUCATION & TRAINING MINISTRY OF HEALTH HANOI MEDICAL UNIVERSITY VU VAN XIEM STUDY ON MORPHOLOGICAL CHARACTERISTICS AND GROWTH OF DENTAL ARCH AND FACE OF A GROUP OF VIETNAMESE MUONG CHILDR[.]
MINISTRY OF EDUCATION & TRAINING MINISTRY OF HEALTH HANOI MEDICAL UNIVERSITY VU VAN XIEM STUDY ON MORPHOLOGICAL CHARACTERISTICS AND GROWTH OF DENTAL ARCH AND FACE OF A GROUP OF VIETNAMESE MUONG CHILDREN FROM 12 TO 14 YEARS OLD Specialty Student No : Odonto and Stomatology : 9720501 SUMMARY OF MEDICAL DOCTORAL THESIS HA NOI - 2022 WORK IS COMPLETED AT: HANOI MEDICAL UNIVERSITY Scientific supervisor: Prof Ph.D.Nguyen Van Ba Ph.D Dang Trieu Hung Opponent 1: Opponent 2: Opponent 3: The thesis will be defended before school level Jury at Hanoi Medical University You can learn about the thesis in: National Library Library of Hanoi Medical University INTRODUCTION The data on morphology and growth of dental arch and face are important because thanks to it, we can plan appropriate orthopedic treatment In the period of 12 to 14 years of age, the permanent teeth are newly formed, there are changes in the size of the dental arches as well as the face compared to other ages and many advantages for performing orthodontics Therefore, the doctor needs to know the basic indicators and changes in the dental arch and face of this age group In the world, many studies have shown the dental arch and face indexes at the age of 12 to 14 In Vietnam, there have been a few studies in Kinh people on this issue, but the sample size is small, and no research has been done in the Muong ethnic group, which is one of the four ethnic groups with the largest population among 54 ethnic groups in Vietnam From the above reasons, we conducted this study to learn about the dental arch and face of Vietnamese Muong children with the project titled: “Study on morphological characteristics and growth of dental arch and face of a group of Vietnamese Muong children from 12 to 14 years old” with the following objectives: Determining some indexes of dental arches and faces of a group of Muong children from 12 years old to 14 years old Describing the growth of dental arches and faces in the above research group THE URGENCY OF THE PROJECT The key to successful treatment in a growing patient is knowing the growth process and if we don't know the exact growth process, the treatment will be ineffective The specific indices and occlusal characteristics vary between races, so when making diagnosis and planning treatment should use the indicators of that race At present, there are no specific indicators of dental arch as well as the growth process of the Muong at the age of 12 to 14 Therefore, we should find out the specific indicators and determine the growth process to apply them in treatment, cosmetology… PRACTICAL SIGNIFICANCE & NEW CONTRIBUTIONS This is the first study to determine the indexes and growth of dental arches and faces of Muong children aged 12-14 years old This is also a study with a large enough sample to be representative of this age group of Muong people in Vietnam Research has found the indicators and growth of dental arch and face of the Muong from 12-14 years old, so that they not have to borrow indexes of other ethnic groups to apply in treatment THE THESIS STRUCTURE In addition to Introduction and Conclusion, the thesis consists of chapters: Chapter 1: Literature Overview, 33 pages; Chapter 2: Research subjects and methods, 30 pages; Chapter 3: Research results, 30 pages; Chapter 4: Discussion, 39 pages The thesis has 26 tables, diagram and 49 chart, 28 images, 122 references (65 references in Vietnamese, 57 references in English) B CONTENTS OF THE THESIS Chapter LITERATURE OVERVIEW 1.1 Morphological characteristics and growth of dental arch and face 1.1.1 Formation and development of the permanent dental arch At each stage, the dental arch has distinct characteristics in terms of morphology, function, growth rate and different correlations 1.1.1.1 The replacement of baby teeth with permanent teeth Calculated from the appearance of the first molars and the baby teeth are replaced by permanent teeth The size of the permanent teeth (except the upper second primary molar and the lower first and second primary molar) are larger than the size of the baby teeth they will replace - The alveolar arch mainly grows horizontally, the anterior growth is not significant Intercanine space increases during the replacement of incisors, averaging about mm, according to Moorrees The upper jaw grows wider than the lower jaw; Males grow more widely than females - Primate gaps between incisors are present during the formation of baby tooth arches - Prolongation of the dental arch due to the permanent teeth usually erupting towards the lips Length increased by about 2.2 mm in the upper jaw and 1.3 mm in the lower jaw When the posterior deciduous teeth are replaced by premolars and permanent canines, the mesial distal dimension of the permanent premolar is smaller than the mesial distal dimension of the primary molar it replaces (the leeway interval) In clinical practice, we can take advantage of the leeway space to prevent RHL1 from moving forward, and at the same time, shift the anterior teeth back to close this space in cases of protruding teeth 1.1.1.2 The change of bite from baby teeth to permanent teeth The development of occlusion from milk teeth to mixed dentition depends on two factors: whether the milk teeth are sparse or tight and the terminal plane of the second baby teeth The correlation of the first molars at the initial contact bite is represented by one of three types of joints: Type I, Type II and Type III: 1.1.2 Occlusion view and classification of occlusion according to Angle 1.1.2.1 Features of a normal occlusion ❖ Correlation between teeth in a jaw - Correlation in the anteroposterior direction: All teeth are in contact in both the mesial and distal surfaces, except wisdom teeth With time, the contact points will become contact planes due to physiological wear under the action of chewing force - External-internal tilt: The upper jaw of the posterior teeth is slightly tilted to the outside, the lower jaw of the posterior teeth is slightly inclined to the inside - Mesio-distal tilt: The upper jaws of the anterior teeth are inclined to mesial and the posterior teeth are inclined distal, the lower jaws of the anterior and posterior teeth are inclined to the mesial - Deep spee curve < 1.5mm ❖ Correlation between upper and lower teeth - Overjet: average is 1-2mm - Overbite: Average Overbite is 1/3 of the lower molar height - Occlusion: line connecting the outer surface of the posterior teeth and the biting margin of the lower anterior teeth 1.1.2.2 Classification of malocclusion according to Angle Angle classifies occlusions into the following four groups: Neutral bite (CLo): The mesial lingual crest of the maxillary first permanent molar engages with the mesial lateral groove of the mandibular (neutral) first permanent molar The teeth are arranged according to the bite line Incorrect bite type I (CLI): The relationship between the upper first permanent molars and the mandibular first permanent molars is neutral, but the bite is not correct because the anterior teeth are misplaced, the teeth rotate, or due to other reasons Class II malocclusion (CLII): The mesiofacial medial cusps of the maxillary first permanent molars articulate mesial relative to the mesial lateral sulcus of the mandibular first permanent molars Type II has two subtypes Class III malocclusion (CLIII): The maxillary first molar proximal lateral cusps articulate distal to the mesiofacial sulcus of the mandibular first molar The lower incisors may be on the outside of the upper incisors 1.1.2 The development of craniofacial The development of the craniofacial complex is associated with the growth of the arch size and the change of occlusion • Postnatal craniofacial development The growth process is represented by three main phenomena: displacement, rotation and development of the dentition The craniofacial complex is divided into regions, these regions have quite different growth: cranial vault, skull base, nasomaxillary and mandibular complex • Direction of teething The eruption direction of the upper molars is downward and slightly forward The eruption direction of the mandibular incisors is upward and slightly anterior The proximal displacement of the molars is greater than that of the incisors during growth, and this proximal migration often leads to a reduction in the arch size • Growth of the dental arch From 12 to 14 years old, most of the HT arch widths of men and women increased, the largest increase was in posterior arch width over men (R77T increased by 0.9mm), only the upper middle width (R55T) ) remained unchanged or decreased slightly The growth change in HD arch width of men and women is similar to that of HT, that is, from 12-14 years of age, these dimensions increase, the largest increase is in posterior arch width less than (R77D) in both men and women From 12-14 years old, in men most of the HT arch length decreases, except for the anterior length of men (D33T), but the change is not much In women, the upper anterior arch length (D33T) and the upper posterior arch length (D77T) increased insignificantly, the upper middle length remained unchanged but the upper rear length (D66T) decreased Similar to the HT arch length, most of the HD arch lengths of males and females from 12 to 14 years of age decreased insignificantly, but the lower posterior arch length of males (D77D) increased slightly • Soft tissue growth after birth Lip growth: The upper and lower lips have the same growth, but the intensity of the upper lip is twice that of the lower lip The upper lip is increasingly receding from the cosmetic line because the growth of the nose is stronger than the growth of the chin 1.2 Methods to study the mophology of dental arches and faces 1.2.1 Methods of measuring and analyzing dental arches and occlusions • Measured on the digitized function sample This is a three-dimensional image, but it is still only two-dimensional on the screen, so it is difficult to identify points, axes and measuring planes • Measured by computer tomography machine Studies have shown that the use of computed tomography is not really necessary when comparing costs and benefits • Measure with a slide ruler on the gypsum jaw specimen 1/100mm precision, easy to use Although there are many ways to evaluate dental arches and occlusion, the method of using electronic slide rulers on gypsum jaw samples is still an effective method suitable for carrying out studies evaluating the changes of teeth, arches and teeth teeth with high precision 1.2.2 Methods of analyzing craniofacial structures 1.2.1 Direct clinical measurement This method is time consuming and requires a lot of experience to determine precise soft tissue benchmarks 1.2.2 Measured on photo This method is commonly used in many different fields such as anthropometrics and criminal justice 1.2.3 Measured on X-ray film Tilted skull X-ray film taken by remote technique helps to evaluate the structure of bone and soft tissue 1.3 Research situation in Vietnam and in the world 1.3.1 Research situation in the world 1.6.2.1 Studies on dental arch size Zsigmundy (1890) was the first person to measure the size of the dental arch, then many authors were interested in this issue such as Moorrees, Meredith, Carter (1997) longitudinal study on the change in arch length and width in adults He concluded that the width, length and circumference of the teeth all decreased by less than mm from 14 to 47 years of age 1.6.2.2 Studies on occlusal changes In 2009, Borzabadi-Farahani and Eslamipou studied the distribution of occlusions in 502 Iranian children aged 11 to 14 years old, and found that the rate of occlusions according to the Angle classification class III was higher than that of Caucasians Sudhanshu Sandhya studied 947 children 12-15 years old, he found that 33.4% of children needed occlusal treatment 1.3.2 Research situation in Vietnam By direct measurement on the jaw sample Le Duc Lanh (2002) shows that: The length of the dental arch in women mostly reaches the adult size at 12 years old for the upper jaw and 15 years old for the lower jaw In Vietnam, there has been no longitudinal study on the morphological characteristics of the dental arch and the change in the size of the dental arch for the Muong, so it is necessary to carry out such a study Chapter RESEARCH SUBJECTS AND METHODS 2.1 Research subjects Children 12 years old, Muong people These children were examined and taken times, each time 12 months apart 2.1.1 Selection criteria at the beginning of the study 12-year-old Muong ethnic children No birth defects, malformations No disease affecting the development of facial arches Children who had not received orthodontic treatment, plastic surgery, facial contouring, maxillofacial trauma until the time of the study The teeth are not damaged, the hard organization loses the length of the dental arch No tooth decay or abnormality in the landmark position There are 28 permanent teeth, no abnormal shape of the teeth Teeth are not crowded or present but to a small extent 2.1.2 Exclusion criteria Children undergoing orthodontic treatment, plastic surgery, facial contouring, maxillofacial trauma during the study period 2.2 Research Methods 2.2.1 Research place and time - Research location: Kim Boi - Hoa Binh - Research period: From November 2016 to November 2021 2.2.2 Research means Electronic ruler, Nikon D700 digital camera, dental examination set, impression spoon, impression material, mixer, computer with VNCEPH measuring software … 2.2.3 Research design According to the vertical tracking descriptive method 2.2.3.1 Sample size and sample selection Sample size for objective 1: Determined according to the formula for calculating sample size of descriptive research Based on the above formula, we calculated the theoretical minimum sample size for both sexes of 196 children In fact, we have studied 226 NC subjects with three sets of function samples and three sets of straight and inclined images Sample size for objective 2: Determined by the formula for calculating sample size comparing the mean of two paired samples (children at 12 years old and 14 years old) The total sample size of the study was 188 children In fact, we have researched 226 research subjects who met all the selection criteria 2.2.3.2 Steps to proceed Data were collected times, once a year Step 1: Choose a locale Step 2: Contact the locality and notify parents to come and take samples Step 3: Preliminary examination, screening, making a list, selecting research subjects Step 4: Take photos, take marks, pour samples - Administrative information: Age (specify date of birth), gender, occupation, address, contact phone number - Habits that are not good for oral health: thumb sucking, lip sucking, mouth breathing - The state of the tooth decay - Determine the occlusal correlation of the following types of occlusion - Class I bite: On both sides of the dental arch, the relationship of the first molars of the upper and lower jaws belongs to the Angle type I relationship - Class II bite: On both sides of the dental arch, the relationship of the first molars of the upper and lower jaws belongs to the type II relationship according to Angle - Class III bite: On both sides of the dental arch, the relationship of the first molars of the upper and lower jaws belongs to the type IIII relationship according to Angle - Mixed bite: The Angle occlusion relationship in the first molars of the upper and lower jaws on both sides of the arch is different (it can be type: Type I-Type II or Type I-Type III) or class II-class III) ➢ Taking impressions, pouring samples ➢ Taking photos: Nikon D700 digital camera Step 5: Measure on sample, on photo Step 6: Enter the data and process the data ❖ Data collection ▪ Collect data about dental arches on jaw samples • Measurement milestones Including 18 milestones: The distal cusps apex of the maxillary second permanent molar, right The apex of the mesial cusps of the The distal cusps of the mandibular second permanent molar, left The apex of the mesial cusps of the maxillary first permanent molar, right The apex of the mesial cusps of the maxillary second permanent premolar, right Top of maxillary permanent canine, right The point between the two upper central incisors The apex of the maxillary permanent canine, left The apex of the mesial cusps of the left maxillary second premolar The apex of the mesial cusps of the maxillary first molar, left side The apex of the distal cusps of the maxillary second molar, left • Dimensions of dental arch width sizes Sizes Width of upper anterior dental arch Upper middle arch width Posterior arch width over Posterior arch width over • mandibular first permanent molar, left The mesial apex of the mandibular second permanent premolar, left Top of mandibular permanent canine, left The point between the two lower central incisors Top of mandibular permanent canines, right The apex of the mesial cusps of the mandibular second premolar, right The apex of the mesial cusps of the mandibular first molar, right Distal cusps apex of mandibular second molar, right Symbol RTT or R33T RGT or R55T RST1 or R66T RST2 or R77T Sizes Front and bottom width Width middle bottom Lower rear rear width Lower rear rear width Symbol RTD or R33D RGD or R55D RSD1 or R66D RSD2 or R77D Dimensions of dental arch length sizes Sizes Length of upper anterior dental arch Upper middle arch length Posterior arch length over Posterior arch length over Symbol DTT (D13T) DGT (D15T) DST1 (D16T) DST2 (D17T) Sizes Length of lower anterior dental arch Length of lower middle arch Back arch length less than Back arch length less than Symbol DTD (D13D) DGD (D15D) DSD1 (D16D) DSD2 (D17D) ➢ Measurement technique - Before measuring, the landmarks on the jaw sample are marked with a 0.5 mm marker - Measuring the arch dimensions, the two vertices of the ruler are placed in the marked position 11 - Measuring instrument: Digital electronic ruler with an accuracy of 0.01 mm, the clamp tip contacts the landmarks accurately - Check the consistency of the measurer: Measure to get the data when the correlation coefficient Pearson ≥ 0.8 - Data processing: Enter data by software with the checking system in the minimum - maximum range 2.7 Research ethics Approved by the Ethics Committee of the state-level project No: 1722/QĐ-ĐHYHN SUMMARY OF THE RESEARCH PROCESS Research sample Examining and gathering information n = 226 DATA COLLECTION Take dental impressions, pour samples n = 226 Taking a photo n = 226 Mistakes and Correction of Mistakes Face data: first time, after 12 months, after 24 months Data of dental arch, first bite, after 12 months, after 24 months DATA PROCESSING Determination of some dental arch and face indexes on jaw samples and on images, Dental arch classificatiscale The growth of dental arch and face sizes over the years from 12 to 14 years old Determine the change of occlusion over the Chapter RESEARCH RESULTS years of the study subjects General characteristics of the study sample In fact, we have studied 226 male subjects, accounting for 47.35% (107 subjects) and female subjects accounted for 52.65% (119 subjects) 12 3.1 The indexes of dental arch and face morphology were measured on dental arch plaster samples and on standardized images of research subjects from 12 to 14 years of age 3.1.1 The morphological indices of dental arch Table 3.1 Dental arch size indicators Male (n=107) Image Age X SD Level of significa nce Female (n=119) X SD P (t-test) Front-Top Width (RTT) (mm) 12 36,21 1,81 *** 35,08 1,89 0,0000 13 36,50 1,76 *** 35,35 1,78 0,0000 14 36,62 1,81 *** 35,52 1,81 0.0000 Upper middle width (RGT)(mm) 12 49,90 2,22 *** 48,17 2,45 0,0000 13 49,97 260 *** 48,25 2,37 0,0000 14 50,24 2,65 *** 48,40 2,40 0.0000 Upper rear width 1(RST1) (mm) 12 54,73 2,21 *** 53,00 2,23 0,0000 13 55,03 2,62 *** 53,23 2,35 0,0000 14 55,40 2,62 *** 53,42 2,45 0.0000 Upper rear width 2(RST2) (mm) 12 59,06 2,65 ** 57,87 2,71 0,0010 13 59,67 2,77 *** 57,90 2,73 0,0000 14 60,40 2,81 *** 58,29 2,92 0.0000 12 27,82 1,69 *** 26,76 1,71 0,0000 13 27,57 2,14 *** 26,71 1,90 0,0000 14 27,85 2,01 0.0000 12 13 14 41,78 41,59 41,79 2,35 2,57 2,66 0,0000 0,0000 0.0000 12 47,08 2,25 *** 45,53 2,21 0,0000 13 47,35 2,58 *** 45,65 2,29 0,0000 14 47,74 2,52 *** 45,84 2,39 0.0000 Lower front width (RTD)(mm) 1,98 *** 26,87 Lower middle width (RGD)(mm) 2,32 *** 39,98 2,55 *** 39,89 2,52 *** 40,06 Lower rear width (RSD1) (mm) 13 12 13 14 54,56 54,77 55,32 12 13 14 8,45 8,55 8,44 12 13 14 22,95 23,13 22,91 12 13 14 29,05 28,92 28,60 12 13 14 44,52 44,71 44,65 12 13 14 5,310 5,35 5,33 12 13 14 18,02 18,37 18,26 12 13 14 24,63 24,55 24,55 12 13 14 39,99 40,59 40,64 Lower rear width (RSD2) (mm) 2,81 *** 52,53 2,60 2,80 *** 52,55 2,46 2,82 *** 53,00 2,53 Upper front length (DTT)(mm) 1,39 * 7,99 1,36 1,44 *** 8,09 1,21 1,37 *** 7,89 1,28 Upper middle length (DGT)(mm) 1,90 *** 22,08 1,77 1,89 *** 22,06 2,05 1,91 *** 22,04 1,65 Upper rear length (DST1) (mm) 2,06 *** 28,08 1,93 2,26 *** 28,05 1,87 2,21 *** 27,82 1,89 Upper rear length (DST2) (mm) 2,46 *** 43,16 2,34 2,72 *** 43,41 2,23 2,59 *** 43,37 2,41 Lower front length (DTD)(mm) 1,07 ** 4,86 1,02 1,06 *** 4,95 1,00 1,08 *** 4,88 0,94 Lower middle length (DGD) (mm) 1,53 *** 17,20 1,54 1,42 *** 17,54 1,44 1,45 *** 17,35 1,36 Lower rear length (DSD1) (mm) 1,82 *** 23,48 1,69 1,74 *** 23,55 1,58 1,73 *** 23,52 1,76 Lower rear length (DSD2) (mm) 2,12 *** 38,68 2,08 2,22 *** 39,12 1,89 2,13 *** 39,21 2,14 0,0000 0,0000 0.0000 0.0135 0,0000 0.0000 0,0005 0,0000 0.0000 0,0003 0,0000 0.0000 0,0000 0,0000 0.0000 0.0016 0,0000 0,0000 0.0001 0,0000 0.0000 0,0000 0,0000 0.0000 0,0000 0,0000 0.0000 Comments: The dental arch sizes in men are larger than in women, the difference is statistically significant (P