Residents’ journal review

Maturation indexes and morphology of the midpalatal suture

Jang HI, Kim SC, Chae JM, Kang KH, Cho JW, Chang NY, et al. Relationship between maturation indices and morphology of the midpalatal suture obtained using cone-beam computed tomography images. Korean J Orthod 2016;46:345-55

Deciding between orthopedic and surgical maxillary expansion is not guided by a hard and fast rule. Although dental tipping is expected in tooth-borne expansion, the extent of transverse correction achieved by buccal movement of the posterior segment beyond the limits of the alveolar housing and the cortical plate increases with skeletal age. Maturation indexes, most commonly the hand and wrist method and the cervical vertebrae method (CVM), are reasonable indicators of remaining skeletal growth but not of the degree of fusion of the midpalatal suture. Therefore, a method to classify the extent of maturation based on the morphology of the midpalatal suture assessed with cone-beam computed tomography (CBCT) has considerable clinical implications. The investigators sought to use such a method, developed by Angelieri et al (Angelieri F, Cevidanes LH, Franchi L, Goncalves JR, Benevides E, McNamara JA Jr. Midpalatal surture maturation: classification method for individual assessment before rapid maxillary expansion. Am J Orthod Dentofacial Orthop 2013:144:759-69) to predict the maturation of the midpalatal suture and to identify a relationship with conventional maturation indexes, if one exists. Midpalatal suture morphology was examined in 99 subjects (ages, 6-20 years) in all planes of space using CBCT images and classified into 5 stages (A-E) according to the classification of Angelieri et al. Hand and wrist method and CVM showed statistically significant correlations (0.904 and 0.874, respectively) with CBCT stage. Stage D or E (fusion of the suture) was not observed in either the male or female group before Suture Maturation Index stage 6. There was no fusion before stage 3 or 4 of the CVM in girls or boys, respectively. The authors concluded that orthopedic maxillary expansion may be recommended before stage 6 in the SMI and before stage 3 in the CVM, whereas a surgical approach may be considered after these stages are recognized. Direct assessment of the midpalatal suture using CBCT images may be clinically beneficial.

Reviewed by Ella Botchevar

Surface-treated orthodontic mini-implants

Kim HY, Kim SC. Bone cutting capacity and osseointegration of surface-treated orthodontic mini-implants. Korean J Orthod 2016;46:386-94

Orthodontic mini-implants (OMIs) have been an invaluable asset to clinicians in contemporary orthodontics. Obtaining absolute anchorage with skeletal implants has been paramount in facilitating tooth movement that might otherwise require extraction of teeth or prolonged use of extraoral anchorage. In uncooperative patients, OMIs have been used to increase predictable treatment outcomes largely because of the wide possibilities of placement. Although success rates are high, failures have been reported from instability, fracture of the OMI, root damage, and inflammation. Treatment success relies on obtaining an effective interface between the OMI and surrounding bone tissues. The authors of this study examined the effects of various surface treatments on the osseointegration and bone-cutting ability of OMIs. Three self-drilling OMIs were compared based on surface treatment: acid etched, resorbable blasting media, and partial resorbable blasting media (hybrid). To compare bone-cutting capacity, artificial bone blocks were made of polyurethane foam to simulate corticocancellous bone. For the comparison of removal torque values, 25 male rabbits had implants placed in tibias and evaluated at 1, 2, 4, and 8 weeks. Histologic analysis for osseointegration was completed with light microscopy and scanning electron microscopy. The results showed that the etched and hybrid groups had lower bone-cutting capacity when compared with the machined (control) group. The hybrid group removal torque significantly increased up to 2 weeks and by 8 weeks was the highest among all groups tested. After evaluation by scanning electron microscopy, only the hybrid group had detectable bone-like tissue. The ability to increase stability while maintaining fracture resistance relies on both macro and micro designs of OMIs. This study showed that hybrid treated OMIs would produce the most stability, offering increased predictability during treatment.

Reviewed by Joseph Facciolo

Surface-treated orthodontic mini-implants

Kim HY, Kim SC. Bone cutting capacity and osseointegration of surface-treated orthodontic mini-implants. Korean J Orthod 2016;46:386-94

Orthodontic mini-implants (OMIs) have been an invaluable asset to clinicians in contemporary orthodontics. Obtaining absolute anchorage with skeletal implants has been paramount in facilitating tooth movement that might otherwise require extraction of teeth or prolonged use of extraoral anchorage. In uncooperative patients, OMIs have been used to increase predictable treatment outcomes largely because of the wide possibilities of placement. Although success rates are high, failures have been reported from instability, fracture of the OMI, root damage, and inflammation. Treatment success relies on obtaining an effective interface between the OMI and surrounding bone tissues. The authors of this study examined the effects of various surface treatments on the osseointegration and bone-cutting ability of OMIs. Three self-drilling OMIs were compared based on surface treatment: acid etched, resorbable blasting media, and partial resorbable blasting media (hybrid). To compare bone-cutting capacity, artificial bone blocks were made of polyurethane foam to simulate corticocancellous bone. For the comparison of removal torque values, 25 male rabbits had implants placed in tibias and evaluated at 1, 2, 4, and 8 weeks. Histologic analysis for osseointegration was completed with light microscopy and scanning electron microscopy. The results showed that the etched and hybrid groups had lower bone-cutting capacity when compared with the machined (control) group. The hybrid group removal torque significantly increased up to 2 weeks and by 8 weeks was the highest among all groups tested. After evaluation by scanning electron microscopy, only the hybrid group had detectable bone-like tissue. The ability to increase stability while maintaining fracture resistance relies on both macro and micro designs of OMIs. This study showed that hybrid treated OMIs would produce the most stability, offering increased predictability during treatment.

Reviewed by Joseph Facciolo

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Apr 2, 2017 | Posted by in Orthodontics | Comments Off on Residents’ journal review
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