Changes of the naso-maxillary complex after rapid maxillary expansion
Bouserhal J, Bassil-Nassif N, Tauk A, Will L, Limme M. Three-dimensional changes of the naso-maxillary complex after rapid maxillary expansion. Angle Orthod 2014;84:88-95
Transverse maxillary deficiency generally presents with other concomitant characteristics such as posterior crossbite, arch-form deformation, dental crowding, or narrowing of the nasal cavity. Rapid maxillary expansion (RME) is commonly used to correct transverse deficiencies. Previous studies have found that RME not only widens the maxilla transversely, but also can have expansion effects on surrounding structures and sutures, including the nasal cavity. These studies have been done to measure the effects on RME with dental casts, cephalograms, and finite element analysis. However, there are limitations to such studies. Therefore, the objectives of this study were to (1) assess the volumetric changes of the naso-maxillary complex after RME, (2) quantify the maxillary and nasal contributions to these changes, and (3) identify the response of the maxilla. Thirty subjects (ages, 7-13 years) with unilateral or bilateral posterior crossbite and requiring RME as part of their orthodontic treatment were selected. Preexpansion and postexpansion computed tomography images were taken. Three-dimensional reconstructions were done using 14 different landmarks. The authors found that all volumetric variables representing the naso-maxillary complex had statistically significant increases after RME. They concluded that the total volume of the naso-maxillary complex increased by 12%. The nasal volume increase represented 30.25% of the total volumetric increase. They also found that the suture response to RME had a triangular opening pattern in the vertical direction, which decreased from the dental arch to the basal bone, as well as in the sagittal direction, with the widest part positioned anteriorly. The results of this study agree with other published results showing a volumetric increase of the naso-maxillary complex after RME. Further prospective studies are indicated to validate these results and further evaluate the relationship between increases in nasal volume and mode of breathing.
Reviewed by Daniel Johnson
White spot lesion treatment modalities
Yuan H, Li J, Chen L, Cheng L, Cannon RD, Mei L. Esthetic comparison of white-spot lesion treatment modalities. Angle Orthod 2014;84:343-9
White spot lesions (WSLs) are a prevalent side effect of fixed orthodontic treatment, affecting about 50% of patients. The aim of this in-vitro study was to compare the esthetic improvements of WSLs treated by 3 common methods—sodium fluoride, casein phosphopeptide amorphous calcium phosphate, and resin infiltration—using spectrophotometer measurements and quantitative light-induced fluorescence. After in-vitro creation of WSLs, measurements of color change (ΔE) and fluorescence loss (ΔQ) by quantitative light-induced fluorescence were performed for each of the 3 treatment groups and the control group (distilled deionized water). The ΔE and ΔQ measurements were repeated at 2-week intervals over a 6-week period, to see whether, with time after the orthodontic treatment, there was improvement or worsening of the WSLs under conditions mimicking the natural oral environment. The results showed that the color of the WSLs in the resin infiltration group was improved significantly by that treatment and had the lowest mean ΔE (2.9 ± 1.2) compared with the other treatment groups (mean ΔE, 12.0 ± 3.6) regardless of time after treatment ( P <0.01). The fluorescence loss in the resin infiltration group was also significantly improved ( P <0.01) after treatment. Because a ΔE value of less than 3.6 is considered a clinically acceptable color difference, an average ΔE of 2.9 ± 1.2 after resin infiltration in the study indicated a better and clinically acceptable color recovery compared with the sodium fluoride and the casein phosphopeptide amorphous calcium phosphate treatments.
Reviewed by Kevin Hallgren
White spot lesion treatment modalities
Yuan H, Li J, Chen L, Cheng L, Cannon RD, Mei L. Esthetic comparison of white-spot lesion treatment modalities. Angle Orthod 2014;84:343-9
White spot lesions (WSLs) are a prevalent side effect of fixed orthodontic treatment, affecting about 50% of patients. The aim of this in-vitro study was to compare the esthetic improvements of WSLs treated by 3 common methods—sodium fluoride, casein phosphopeptide amorphous calcium phosphate, and resin infiltration—using spectrophotometer measurements and quantitative light-induced fluorescence. After in-vitro creation of WSLs, measurements of color change (ΔE) and fluorescence loss (ΔQ) by quantitative light-induced fluorescence were performed for each of the 3 treatment groups and the control group (distilled deionized water). The ΔE and ΔQ measurements were repeated at 2-week intervals over a 6-week period, to see whether, with time after the orthodontic treatment, there was improvement or worsening of the WSLs under conditions mimicking the natural oral environment. The results showed that the color of the WSLs in the resin infiltration group was improved significantly by that treatment and had the lowest mean ΔE (2.9 ± 1.2) compared with the other treatment groups (mean ΔE, 12.0 ± 3.6) regardless of time after treatment ( P <0.01). The fluorescence loss in the resin infiltration group was also significantly improved ( P <0.01) after treatment. Because a ΔE value of less than 3.6 is considered a clinically acceptable color difference, an average ΔE of 2.9 ± 1.2 after resin infiltration in the study indicated a better and clinically acceptable color recovery compared with the sodium fluoride and the casein phosphopeptide amorphous calcium phosphate treatments.
Reviewed by Kevin Hallgren
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