TOMOGRAPHIC DIMENSIONS FOR THE INSTALLATION OF RAPID MAXILLARY EXPANSION MINI-IMPLANTS IN DIFFERENT AGE GROUPS

Objective: The purpose of the research was to compare the dimensions of the upper jaw between different age groups for the installation of mini-implants for rapid maxillary expansion. Materials and Methods: The study was descriptive, retroprospective and observational. Cone beam computed tomography was used for the evaluation of 30 patients between 7 and 56 years of age, divided into three groups, ten up to 14 years, ten from 15 to 30 years, and ten from 31 years and older. The premolar and molar regions were selected for the measurement of the maxilla in the coronal plane, both bone and soft tissue. To compare the measurements, the Kruskal Wallis and Mann-Whitney U tests were used. Results: No statistically significant differences were found between the groups. The thicknesses of the bone tissue decreased from the first premolar to the second molar from 9.48 +/-3.71 mm to 5.40 +/-2.80 mm respectively, while the soft tissue thicknesses were more homogeneous with measurements of 0.56 +/-0.74 mm to 2.76 +/- 2.42 mm. Conclusions: The dimensions of the bone and soft tissue of the upper jaw, evaluated vertically for the installation of mini-implants, were similar in all the age groups studied, with larger dimensions in men than in women at the premolar level. The dimensions of the maxilla for the palatal miniimplants were close to 9 mm in bone tissue and 3 mm of soft tissue at the level of premolars and 5 mm in hard tissue with 1 mm of soft tissue at the level of molars.


INTRODUCTION
Rapid maxillary expansion (RME) is considered a common treatment for transverse maxillary deficiencies, 1-4 present in all age groups, 5 which consists of increasing the transverse dimension of the maxilla using different types of devices that achieve considerable maxillary expansion. 6-8Knowledge of the linear values of the upper jaw is the basis for planning orthodontic treatments that require RME, 9-11 such as mini-implant-assisted rapid palatal expansion (MARPE), which generates an increase significant in the transverse maxillary skeletal dimension, showing a more parallel radiolucency of the palatal suture than traditional methods, causing fewer collateral effects on the posterior teeth, such as the greater angulation of the molars generated by dental support methods. 8late has become an important site for the placement of anchorage devices, due to its bone quantity and quality, 9 especially if RME is desired. 6 However, it is necessary to know if these dimensional changes also occur with age in the area where mini-implants for RME are usually placed.
Eslami et al., 11 observed a progressive increase in various measurements of the palate from birth to the period of permanent dentition.
Berwig et al., 14 indicated that the dimensions of the maxilla were different according to sex, being larger in men.Liu et al. 15 indicated that the thickness of the palate was influenced by sex, age, and their interaction.Mallick et al. 16 evaluated the thickness of the cortical bone of the lingual and palatal jaws to choose the optimal locations to place the mini-implants, but they did it just at the interradicular level.
To perform RME, the mini-implants need to be placed in the region paramedial to the palatine raphe. 17By comparing the dimensions of the upper jaw between different age groups using computed tomography in this region, it could provide more information to the orthodontist about the base dimensions in both hard and soft tissue to take into account when selecting mini-implants for RME.
The purpose of the study was to compare the dimensions of the jaw between different age groups for the installation of RME miniimplants.(M2), with a separation of 1 mm between each measurement, -10 to +10 mm, with the palatine raphe being measurement 0 (Figure 1).

Method error
The error of the method was evaluated with In order to evaluate the agreement, the Intraclass Correlation Coefficient was used, obtaining values greater than 0.90 (p<0.05) for both measurements.

Statistic analysis
The data were processed using the SPSS Sta-    Likewise, statistically significant differences were found in the thickness of the soft tissue (p=0.029) between the group up to 14 years old and the group from 15 to 30 years old, where the latter showed lower thickness with 1.76 +/-1.43 mm (Table 2).

DISCUSSION
Mini-implant-assisted for RME, or MARPE, is a means of expanding basal bone without surgical intervention in adolescent patients 18 and young adults, 8 which has been shown to be a treatment modality that is associated with a high success rate in maxillary expansion, skeletal and dental, 19 which is why it is important to know how the dimensions of the maxilla are manifested, in the palatal region, where the mini-implants intended to be used with MARPE are placed.
The findings of the present study showed no evidence of differences in the dimensions of the upper jaw for the insertion of rapidly expanding mini-implants between the age groups studied; however, the dimensions decreased from the first premolar to the second  15 where the hard tissue was thickest in P1, followed by the planes of P2, M1 and M2, while the thickness of the soft tissue was similar in the four planes. 15fferences were recorded in P1 for soft tissue in the group up to 14 years old between males and females, and in P2 for hard tissue in the group from 15 years to 30 years between males and females.In both cases, larger dimensions were observed in men than in women, similar to what was reported by Berwing et al., 14 who found larger dimensions in men than in women in both the first and second premolars.
On the other hand, Eslami et al., 11 stated that there are no differences in the height of the palate and in the molar area between men and women, coinciding with this study in the area of M1 and M2.
Yu et al., 22 and Ning et al., 24 stated that the palatine bone was thicker in men than in women and that there were no sexrelated differences in the posterior palate.There was a trend for thickness to decrease in the poszterior direction, but less pronounced in women.These results differ from the present study since in the measurements carried out no differences were found according to sex at execution of this research work was approved by the research committee of the Santo Toribio de Mogrovejo Catholic University, with resolution number 199-2022-USAT-FMED.An observational, descriptive, retroprospective study was carried out.The study population was made up of patients who attended a local radiological center in the city of Trujillo, Peru, between 2021 and 2022, from which a sample of 30 tomography scans was extracted, in which 1260 tomographic sectors were evaluated.The sample was calculated using the formula for comparison of means, with data obtained from a pilot study, carried out with 168 tomographic sectors from first premolars to second molars 42 tomographic sectors (corresponding to two patients, 168 tomographic sectors at each observation moment) through inter-examiner cali-bration between the researcher and a specialist radiologist, after the researcher's training; and intra-examiner calibration between the same researcher at two different times, with two weeks of separation between measurements.

tistics 22 .
0 statistical program (IBM, Armonk, NY, USA).The means, standard deviations, medians, minimum and maximum values were calculated.To determine the comparison of the dimensions of the upper jaw between the different age groups, the Kruskal Wallis test was used for multiple comparisons and the Mann-Whitney U test for post-hoc comparisons and for comparisons between men and

Figure 1 .
Figure 1.Representative tomographic image of the measurement of the height of the maxillary bone, carried out at the level of the upper first premolars, in the axial plane, in A. In B, the coronal plane is shown at the level of the first premolars themselves with the 11 measurements made for both soft tissue (in blue) and bone tissue (in red), with a separation of 1 mm for each measurement, as seen in the area with the yellow arrow.
Selection of the appropriate length of the mini-zimplant for the use of MARPE is an important factor in obtaining good anchorage.The results of the present study show that the lengths of the mini-implants for all groups could be around 9 mm at the premolar level and around 5 mm at the molar level, with transmucosal zones, for soft tissue, close to 3 mm in pre-molars and 1 mm in molars.These reference data are important and could be considered as a basis to more accurately iden-tify more personalized values in each patient with their own planning tomography.Likewise, it is important to consider the greater thickness of some dimensions in men, especially at the level of premolars.It is relevant to also take into account the presence of other factors for the success of maxillary disjunction, such as stationary quality, insertion sites, placement procedure, immediate or early loa-ding assignment, minimum compliance with indications by of the patient, the characteristics of the oral mucosa, the state of health of the organism and the quality of oral hygiene.CONCLUSIONThe dimensions of the bone and soft tissue of the upper jaw, evaluated vertically for the installation of mini-implants, were similar in all the age groups studied, with larger dimensions in men than in women at the premolar level.The dimensions of the maxilla for the palatal miniimplants were close to 9 mm in bone tissue and 3 mm of soft tissue at the level of premolars and 5 mm in hard tissue with 1 mm of soft tissue at the level of molars.Cardozo-Muñoz AK & Carruitero MJ.Tomographic dimensions for the installation of rapid maxillary expansion mini-implants in different age groups.J Oral Res.2023; 12(1): 288-298.https://doi.org/10.17126/joralres.2023.025and that the original publication in this journal is cited, in accordance with accepted academic practice.No use, distribution or reproduction is permitted which does not comply with these terms.© 2023.PEER REVIEW This manuscript was evaluated by the editors of the journal and reviewed by at least two peers in a double-blind process.PLAGIARISM SOFTWARE This manuscript was analyzed by Turnitin's Original plagiarism detector software.Analysis report of document (ID.3d45e5b5b96a781076485 a7efb73e9bcd6d5a57c) ISSN Print 0719-2460 -ISSN Online 0719-2479.https://www.joralres.com/index.php/JOralRes/issue/archive

Cardozo-Muñoz AK & Carruitero MJ.
Tomographic dimensions for the installation of rapid maxillary expansion mini-implants in different age groups.

Oral Res.2023; 12(1): 288-298. https://doi.org/10.17126/joralres.2023.025Table 1 .
Tomographic dimensions for the installation of rapid maxillary expansion mini-implants in different age groups.J Comparison of the dimensions of the upper jaw between the different groups of age in study.

Oral Res.2023; 12(1): 288-298. https://doi.org/10.17126/joralres.2023.025 the
Tomographic dimensions for the installation of rapid maxillary expansion mini-implants in different age groups.J level of the entire bone tissue, but only in the group of 15 to 30 years at the level of the