Evaluation of the effectiveness of maxillary protraction applied between the ages of 4-7

The Class III malocclusion can be observed with deficient and retrognatic maxilla, large and prognatic mandible, or the combination of these conditions. Orthopedic devices can be used in the early treatment of Class III malocclusion cases presenting maxillary retrognathia. In the late period, compensation with fixed orthodontic treatment mechanics or orthodontics combined with orthognathic surgery might be necessary. Different approaches for the orthopedic treatment of the Class III malocclusion have been reported in the literature. Since maxillary defficiency accounts for 60% of the cases presenting Class III malocclusion, the most commonly recommended treatment protocol for this anomaly involves rapid maxillary expansion and protraction of the maxilla using a face mask in growing individuals. Early treatment of maxillary retrognathia is important in terms of preventing the need for orthognathic surgery in the future, saving patients from an invasive and expensive procedure, and positively supporting psychosocial development. Furthermore, when surgical intervention is unavoidable, maxillary protraction plays a critical role in reducing the severity of the developing malocclusion and improving the profile. 10 years for girls and 11 years for boys are generally accepted as the limit age for devices that allow face mask or other orthopedic correction, since the maxilla completes its sagittal growth and these ages coincide with the period before the prepubertal growth spurt. In addition, the treatment of skeletal malocclusion that develops during the first growth spurt, which is accepted to occur between the ages of 4-7, may allow the surrounding tissues, especially the mandible, to develop within a more appropriate functional envelope. In this small age group (4-7 years old), clinically significant improvements are observed in individuals who wear the appliances for a shorter period of time with lower force compared to the conventional age group (8-11 years old). However, the number of studies reporting the results of the face mask applied in the early period is quite limited in the literature. In the literature, the use of face masks is recommended for 12 to 24 hours a day, and the amount of force is recommended with values ranging from 300 to 600 grams. Significant changes can also be observed in patients who state that they only use face masks during bed time. This finding has led us to question the duration of daily use, because in the literature, the recommended duration of appliance wear for the patient is included in the studies evaluating the face mask treatment, but the amount of studies inwhich an objective record of the duration of use is limited. The record of the duration of appliance usage is based on the patient's statement and the doctor's clinical observation. However, these methods might be compromised due to the optimistic statements of the patients and the subjective estimations of the clinicians. Various devices have been developed to objectively measure patient compliance and determine the treatment protocol accordingly. Nowadays the use of microelectronic sensors, which can be mounted on orthopedic appliances with their small size and enabling objective data recording with their high technological features, is becoming widespread. TheraMon® (MC Technology GmbH, Hargelsberg, Austria) is a microsensor system that facilitates the acquisition of objective cooperation data. The aim of our study is to compare the effectiveness of face mask used at the transition to mixed dentition period (4-7 years old) compared to the usage during the prepubertal period (between 8-11 years) with a recommended daily use of 9-11 hours and with 450 grams of protraction force. Our hypothesis is that there will be no difference in terms of skeletal and soft tissue parameters between younger (4-7 years old) and older (8-11 years old) groups whose cooperation is monitored with digital data and treated for the same duration and with the same amount of force. The two groups were formed with individuals having similar initial malocclusion parameters. Patients in both groups underwent rapid maxillary expansion with an acrylic cap splint appliance followed by face mask treatment. The face mask, which was recommended to be used for 10 hours a day, was applied with 450gr of force per side until Class II canine relationship was achieved. In order to monitor the patients' cooperation with concrete data, TheraMon® (MC Technology GmbH, Hargelsberg- Austria) microsensors were integrated into the forehead part of the face mask. Skeletal, dental and soft tissue parameters were determined and measured on lateral cephalometric x-rays taken before the treatment (T0) and after the end of the face mask application following rapid maxillary expansion (T1). Cephalometric analyzes were performed with the Nemoceph® (Copyright© NEMOTEC, Madrid-Spain) software. Data recorded with TheraMon® (MC Technology GmbH, Hargelsberg-Austria) were monitored with its sensor reader. The age when the treatment started was statistically significantly higher in the 8-11 age group, and gender and treatment duration did not show a significant difference between the 8-11 age and 4-7 age groups. Daily usage time was recorded as 8.9+1.8 hours in the 4-7 age group and 7.1+0.9 hours in the 8-11 age group. In light of these data, daily usage time is statistically significantly higher in the 4-7 age group compared to the 8-11 age group. The increase observed in the sagittal skeletal values SNA°, A-Nasionperp (mm), ANB°, Wits (mm) and Maxillary Depth (°) parameters between the beginning and the end of treatment in both groups was found to be statistically significant. SNB° value decreased statistically significantly from T0 to T1 only in the 4-7 age group. The Co-A (mm) parameter showed a statistically significant increase only in the 8-11 age group. The increase in the ANS-Me (mm) parameter, which is the vertical skeletal values, from T0 to T1 was found to be statistically significant in both groups. N-Me (mm) and SN-GoGn (°) values showed a statistically significant increase from T0 to T1 only in the 4-7 age group. Saddle Angle (°) and Articular angle parameters showed a statistically significant increase from T0 to T1 only in the 8-11 age group. A statistically significant increase was detected in Molar Relationship (mm) and Overjet (mm) parameters in both groups. L1-A/Pg dental parameter showed a statistically significant decrease in the 8-11 age group. Positive improvements were achieved in the parameters indicating the position of the maxilla in both groups, the maxilla developed in the sagittal direction and the relationship between the jaws improved. Changes in many skeletal and soft tissue parameters were found to be similar between the two younger and more older groups treated with the same amount of force and recommended use for the same duration. Since differences were observed in some parameters, the null hypothesis was partially confirmed. The fact that the amount of daily appliance use in the early age treatment group (between the ages of 4-7) is higher compared to the older age group (between the ages of 8-11) emphasizes the importance of choosing the age of starting treatment in treatments where cooperation is required.