Biomechanics of conventional and miniscrew-assisted rapid palatal expansion.

• This review article focuses on the biomechanics of conventional rapid palatal expansion (RPE) and miniscrew-assisted rapid palatal expansion appliances (MARPE). • Three main things play an important role in the type of movements that follow rapid maxillary expansion: 1) Center of resistance and anatomy of maxilla, 2) Appliance system, and 3) Forces, Stress, and Strain. • The nature of forces after expansion is cyclical with force activation and decay occurring after each turn/activation of the expansion appliance. • The stress levels expressed by RPE and MARPE are different which is responsible for the difference in the effects because of RPE and MARPE • Even within MARPE, bone-anchored MARPE design and hybrid MARPE design result in different force systems or stress on the oral structures. Posterior Crossbite is a common condition resulting because of transverse maxillary deficiency. The growth of the craniofacial complex finishes first in the transverse dimension, followed by sagittal and vertical dimensions. Conventional rapid palatal expansion (RPE) appliances are commonly used to correct transverse maxillary deficiency. Although RPE is efficient in correcting posterior crossbite, it results in dental side effects such as buccal tipping of maxillary molars, root resorption, bone dehiscence, and relapse. Mini-implant-assisted RPE has been introduced to increase the skeletal effects of expansion especially in patients with increased maturation and greater interdigitation of midpalatal suture. This article will review the biomechanics of RPE and mini-implant-assisted RPE. Additionally, the different designs of MARPE and the long-term clinical effects of expansion appliances will also be discussed in detail. [ABSTRACT FROM AUTHOR]