Comparison Between Two Rates of Activation of Miniscrew-Supported Upper Jaw Expander in Adolescents

Comparison Between Two Activation Protocols of Miniscrew-Supported Maxillary Expander in Adolescents: A Randomized Controlled Clinical Trial

Miniscrew-supported maxillary expanders provide advantages over conventional tooth-supported expanders. However, there is no consensus in the literature regarding their activation protocol. The purpose of the clinical trial is to evaluate and compare the effects of slow and rapid activation rates of miniscrew-supported expanders on the skeletal changes, dento-alveolar changes and the pain experience.

Transverse maxillary deficiency is one of the problems that are commonly encountered in the orthodontic practice. Miniscrew-supported maxillary expansion represents a promising modality for the treatment of transverse maxillary deficiency. However, controversies still exist regarding the activation protocol. One of these controversies is whether using a slow activation protocol would be more beneficial to the patients compared to a rapid activation protocol. Another question that consequently ensues is whether such activation protocol would result in less pain compared to the rapid activation protocol. The null hypothesis of the current study is that there is no difference between slow and rapid activation protocols of miniscrew-supported expander.

The miniscrew-supported maxillary expander is activated by turning the expansion screw once every other day.

A maxillary expander is supported on 4 palatal miniscrews. The appliance is activated slowly by turning the expansion screw once every other day to correct the transverse maxillary deficiency.

A maxillary expander is supported on 4 palatal miniscrews. The appliance is activated rapidly by turning the expansion screw twice per day to correct the transverse maxillary deficiency.

Transverse skeletal changes from baseline to an average of 5 months after the initial activation, measured using cone beam computed tomography (CBCT)

The data from CBCT scans at the different time points will be exported in Digital Imaging and Communications in Medicine (DICOM) format and processed using suitable software. The relevant landmarks will be defined and located by the investigator to measure the transverse skeletal changes in mm from baseline to the end of passive retention of the expansion.

Dento-alveolar inclination changes from baseline to an average of 5 months after the initial activation, measured using CBCT

The data from CBCT scans at the different time points will be exported in DICOM format and processed using suitable software. The relevant landmarks will be defined and located by the investigator to measure the changes in dento-alveolar inclination from baseline to the end of passive retention of the expansion.

Measures pain and how it affects the daily activities on a NRS where each respondent selects a whole number, between 0 and 10, with 0 being the lowest extreme and 10 being the highest extreme.

Measures pain and how it affects the daily activities on a NRS where each respondent selects a whole number, between 0 and 10, with 0 being the lowest extreme and 10 being the highest extreme.

Measures pain and how it affects the daily activities on a NRS where each respondent selects a whole number, between 0 and 10, with 0 being the lowest extreme and 10 being the highest extreme.

Measures pain and how it affects the daily activities on a NRS where each respondent selects a whole number, between 0 and 10, with 0 being the lowest extreme and 10 being the highest extreme.

At the end of active expansion (an estimated average of 2 to 3 weeks in the rapid expansion group, and 7 to 12 weeks in the slow expansion group)

Inclusion Criteria: Permanent dentition. Participants indicated for skeletal maxillary expansion due to unilateral or bilateral posterior cross bite or maxillary transverse deficiency Good oral hygiene Exclusion Criteria: History of previous orthodontic or orthopedic treatment History of maxillary trauma Patients with congenital craniofacial malformations Patients receiving pharmacological agents or having systemic diseases that might affect the bone metabolism or the pain response

Lin L, Ahn HW, Kim SJ, Moon SC, Kim SH, Nelson G. Tooth-borne vs bone-borne rapid maxillary expanders in late adolescence. Angle Orthod. 2015 Mar;85(2):253-62. doi: 10.2319/030514-156.1. Epub 2014 Dec 9.

Yilmaz A, Arman-Ozcirpici A, Erken S, Polat-Ozsoy O. Comparison of short-term effects of mini-implant-supported maxillary expansion appliance with two conventional expansion protocols. Eur J Orthod. 2015 Oct;37(5):556-64. doi: 10.1093/ejo/cju094. Epub 2015 Jan 6.

Lagravere MO, Carey J, Heo G, Toogood RW, Major PW. Transverse, vertical, and anteroposterior changes from bone-anchored maxillary expansion vs traditional rapid maxillary expansion: a randomized clinical trial. Am J Orthod Dentofacial Orthop. 2010 Mar;137(3):304.e1-12; discussion 304-5. doi: 10.1016/j.ajodo.2009.09.016.

Algharbi M, Bazargani F, Dimberg L. Do different maxillary expansion appliances influence the outcomes of the treatment? Eur J Orthod. 2018 Jan 23;40(1):97-106. doi: 10.1093/ejo/cjx035.

Carvalho Trojan L, Andres Gonzalez-Torres L, Claudia Moreira Melo A, Barbosa de Las Casas E. Stresses and Strains Analysis Using Different Palatal Expander Appliances in Upper Jaw and Midpalatal Suture. Artif Organs. 2017 Jun;41(6):E41-E51. doi: 10.1111/aor.12817. Epub 2016 Dec 7.