Hakan N. İşcan

Comparison of the effects of passive posterior bite-blocks with different construction bites on the craniofacial and dentoalveolar structures

Posterior bite-blocks that are used in the early treatment of skeletal open bite, produce a forward and upward mandibular rotation by transmitting the masticatory muscle forces to the buccal dentoalveolar regions and preventing their vertical growth. Increasing the vertical dimension of the face artificially causes skeletal adaptations to occur not only in the dentoalveolar region but also in the other regions of the craniofacial complex. The affects of passive posterior bite-blocks, constructed in two different heights, were investigated for two treatment groups, in comparison to an untreated control group. Two treatment groups comprised of 25 growing patients, who had skeletal open bite and skeletal/dental Class I or Class II malocclusions, and one control group consisting of 14 growing patients were used. These groups were matched concerning their age, sex, and vertical and sagittal skeletal cephalometric and dental characteristics. Passive posterior bite-blocks of 5 and 10 mm heights were applied to the subjects of the treatment groups respectively for 18 hours per day. Untreated control subjects were observed for 7 to 9 months. The findings of this study revealed that the downward and backward mandibular rotation continued in the control group, increasing the lower facial height significantly, whereas in the treatment groups, the skeletal open bite was treated and the mandible rotated upward and forward. The increase of the height of the posterior bite-blocks had a significant effect on the anterior mandibular rotation and in the increase of the gonial angle.

Functional and fixed orthodontic treatment in a child with cerebral palsy

Cerebral palsy is a permanent neuromuscular motor disorder that results from injury in the developing brain during the prenatal or postnatal period. Common functional and craniofacial problems related to cerebral palsy include impaired swallowing, chewing, and speech; maxillary transverse deficiency; excessive anterior facial height; and Class II malocclusion. This article reports the treatment of a 12-year-old girl with ataxic cerebral palsy; she had a dental and skeletal Class II malocclusion, maxillary transverse deficiency, and severe crowding in both arches. Treatment included rapid maxillary expansion with simultaneous functional therapy and fixed orthodontic extraction therapy in a period of 2 years 3 months. Vertical control was maintained by a vertical chincap. An acceptable occlusion and improvements in facial esthetics, speech, and oral function were achieved.

The effects of cervical headgear with an expanded inner bow in the permanent dentition

In this study, the effects of cervical headgear (CHG) use on the transverse dimension of the maxillary dental arch were evaluated in patients in the permanent dentition. Thirteen girls and 12 boys (mean age: 13.41 +/- 0.52 years) with a bilateral full cusp Class II molar relationship comprised the study group. Fifteen girls and 10 boys with a Class I normal occlusion comprised the controls. In the treatment group, CHG with an expanded inner bow was used for a mean period of 11.2 +/- 5.6 months. The headgear was used for molar distalization and the force magnitude was 196.1 cN. After CHG treatment, the patients underwent non-extraction fixed orthodontic treatment for 14.1 +/- 2.5 months. During this period, the control group received regular dental check-ups. Dental casts obtained at the beginning (T1) and end (T2) of headgear use and at the end of orthodontic treatment (T3) and posteroanterior cephalograms taken at T1 and T2 were evaluated. A Students t-test was used for intergroup comparison at T1, T2, and T3 and a Mann-Whitney U-test with a Bonferroni correction for comparison of treatment/observation changes. At T2, intercanine (0.96 +/- 0.56 mm), interpremolar (1.6 +/- 0.55 mm for the first premolar, 1.74 +/- 0.65 mm for the second premolar), and intermolar (2.31 +/- 0.75 mm) widths increased, while the distance between the intersection of the zygomatic process and the maxillary alveolar process on the right (JR) and left (JL) did not change. Fixed orthodontic treatment did not have any effect on any of the measurements. With the intentional expansion of the inner bow of CHG, the amount of maxillary dental arch expansion achieved in the permanent dentition was statistically significant (P < 0.017).

Evaluation of extraction and non-extraction treatment effects by two different superimposition methods

The aim of this study was to determine whether different evaluation methods may be the cause of the varied outcomes of research that have evaluated the effects of extraction and non-extraction therapy on jaw rotation. This retrospective study consisted of the pre- (T1) and post- (T2) treatment lateral cephalograms of 70 skeletal Class I subjects with an optimal vertical mandibular plane angle, who had undergone fixed orthodontic treatment. Thirty-five of the subjects (20 females and 15 males, mean age: 14.7 years) were treated with four first premolar extractions and 35 (22 females and 13 males, mean age: 15 years) without extractions. T1 and T2 radiographs were superimposed using Björks structural method and Steiners method of sella-nasion line registered at sella. A Wilcoxon test was used to evaluate the changes between T1 and T2 and the Mann-Whitney U-test to determine differences between the extraction and non-extraction and Björk and Steiner groups. No significant difference was found between the methods of Steiner and Björk according to the spatial changes of the cephalometric points in the extraction and non-extraction groups. The maxilla showed forward rotation in the extraction group and backward rotation in the non-extraction group with both superimposition methods, but the differences were not significant in either inter- or intraclass comparisons. The mandible showed forward rotation in the extraction group with both superimposition methods but, in the non-extraction group, forward rotation was recorded with Björks method and backward rotation with Steiners method. These findings were not significant in either inter- or intraclass evaluations. No significant difference was found between the groups or methods.