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Biomedical subjects

O Uner

Publications and source records attributed to O Uner.

12 recordsLinked to original sources
PubMed1997

The drum spring (DS) retractor: constant and continuous force for canine retraction.

Although much research has been undertaken on the rate of tooth movement, with different hypotheses having been put forward, the concepts of the threshold, light, heavy and optimal forces are not still clear. It has been stressed that an ideal orthodontic spring should have the ability to release a constant force throughout the entire range of its activation, but using traditional techniques applied initial force will decrease, depending on its deactivation due to the tooth movement and the physical properties of the force delivery system. The purpose of this study was to test the clinical use of a new and original spring, the drum spring (DS) retractor (developed in 1992), which applies a constant and continuous force without the need for reactivation, and to compare the effect of a constant and continuous force versus a continuous but diminishing force produced by a traditional pull coil (PC) retractor system on the rate of upper canine retraction. The clinical sample consisted of 15 patients with upper first premolar extractions. For each patient, the upper right canine was retracted by using a DS retractor applying a constant and continuous force of 50 g; the upper left canine was fitted with a conventional PC applying an initial force of 50 g, diminishing proportionally with the distal movement of the canine. In addition, each group was divided according to the age of each patient: eight patients (three males, five females) between 11.8 and 14.4 years of age (mean 13 +/- 1.2 years) represented the adolescent group, and seven patients (three males, four females) between 18.8 and 21.6 years of age (mean 18.2 +/- 1.9 years) representing the adult group. The experimental period started 1 week after the extraction of the first premolars. During this period no archwire was used, to avoid friction and force level changes, and the both springs were attached to a 6 mm hook fixed on the canine bracket to reduce tipping. The PC retractor was reactivated every 3 weeks whereas the DS retractor was left untouched over the entire experimental period. The study was continued until one of the two canines was completely retracted. The DS retractor was successful for space closure without any reactivation, and the continuous and constant force provided a more rapid canine movement than the continuous but diminishing force. Canine retraction occurred faster in adolescents than in adults. An entire field of clinical and research applications may be influenced by this new type of spring.

Adolescent↗
PubMed1996

Enamel fluoride levels after orthodontic band cementation with glass ionomer cement.

The aim of this investigation was to examine the fluoride uptake by enamel after application of glass ionomer cement for orthodontic band cementation compared with zinc phosphate cement. The study was conducted on 21 children whose mean age was 14 years. All the children were reared in the Middle Anatolian cities where the water fluoride concentration was below the level of 0.50 ppm. The subjects were randomly divided into three groups. The first experimental group, had seven subjects whose teeth were topically fluoridated with 2 per cent NaF solution, before orthodontic band cementation with zinc phosphate cement. The second experimental group also had seven subjects whose orthodontic bands were cemented with glass ionomer cement. The third group, consisted of seven control subjects and no dental procedures were performed in this group. All the participants were followed for 3 months and at the end of this period maxillary first premolars, which were in the ninth developmental stage according to Nolla (1960), were extracted for orthodontic purposes. The enamel fluoride concentrations were determined on the left maxillary first premolars at three successive etch depths by means of a fluor ion electrode, whereas the calcium concentrations were determined with an atomic absorption spectrophotometer. The results of this investigation showed that in both cementation groups enamel fluoride concentrations at three successive etch depths were highly increased compared with the control group. However, the difference between the cementation groups was not statistically significant.

Adolescent↗
PubMed1996

Effects of a modified maxillary orthopaedic splint: a cephalometric evaluation.

Taking the presence of an interplay between the vertical and sagittal components of craniofacial development into consideration, the beneficial therapeutic potential impacts of controlling vertical development on the correction of Class II discrepancies has been previously investigated. In the present study, a modified maxillary orthopaedic splint combined with an anterior high-pull headgear was used for early correction of the vertical and consequently sagittal dentoskeletal discrepancy as the initial stage of treatment. The aim was to evaluate its effects on the maxillary and mandibular dentoskeletal development, as well as rotational growth pattern. In order to compare with and distinguish from the uninterrupted growth changes, a control group was formed by matching each one of the control subjects to a subject in the treatment group according to certain criteria. The initial and second standardized lateral cephalograms of each subject was evaluated by means of an adopted and biologically more substantial cephalometric analysis. Evaluation of the changes induced by the splint in comparison with the uninterrupted growth changes revealed that the splint had both orthopaedic and orthodontic effects on the growth pattern of the dentoskeletal structures. There seemed to exist a relationship between the direction of total mandibular and maxillary rotations. In addition, it was believed that in order to cause a forward mandibular rotation, i.e. to change the rotational mandibular growth pattern from a backward into a forward direction, the posterior vertical maxillary development should be restrained, but anterior vertical maxillary development should be relatively more restrained or reversed and, thereby, the rotational growth pattern of the maxilla should be changed from a backward into a forward direction. Moreover, the bite block effect of the splint seemed to cause a favourable change in the condylar growth direction from a backward to an upward direction.

Case-Control Studies↗
PubMed1995

Long-term evaluation after chincap treatment.

The purpose of this study was to investigate the skeletal changes occurring during and after chincap therapy. The subjects of this study, with a mean age of 9 years 3 months, consisted of 27 patients; all of whom possessed an anterior crossbite. Of these patients, 15 had skeletal Class III and the remaining 12 had skeletal Class I malocclusions with anterior crossbites. The applied total force with the chincap was 600 grams and the mean treatment period was 12 months. The changes during and after treatment were analysed by using linear and angular cephalometric measurements. The result obtained in this investigation was that in skeletal Class I and Class III cases, successfully treated by a chincap appliance, where the necessary overjet and overbite relationship was obtained, the abnormality tended to return to the original position during the period following chincap removal.

Cephalometry↗
PubMed1994

Delayed calcification and congenitally missing teeth. Case report.

A case of delayed differentiation and/or calcification, that is, development, followed by accelerated growth of the maxillary second premolars is presented. This condition was accompanied by the congenital absence of mandibular second premolars even though maxillary and mandibular third molar germs were present. The case was followed over a five-year period. It seems that agenesis of any tooth might be found in conjunction with delay in development of any other tooth. Moreover, full development of a tooth germ (followed by an accelerated growth) as well as pathological changes may occur, despite an initial marked delay in tooth development.

Anodontia↗
PubMed1994

The effects of cervical headgear on dentofacial structures.

A study was made on the effects of cervical headgear on dentofacial structures, especially non-erupted teeth, in the early and late mixed dentition periods. Pretreatment and post-treatment cephalometric evaluation was done on 8 patients in the early mixed dentition period and 10 patients in the late mixed dentition period. The results showed that any reference line passing through Ptm point should not be used to evaluate the efficiency of cervical headgear, and that such headgear is more effective on non-erupted teeth in early mixed dentition.

Bicuspid↗
PubMed1990

[The effect of growth and development on soft tissue profile in boys and girls with normal occlusion].

In this study the effect of the growth and development on soft tissue profile of preadolescent subjects with normal occlusion, skeletal class 1 and mesiodivergent structure was investigated. 10 girls, the mean skeletal age being 9.28 +/- 1.58 years and 10 boys, the mean skeletal age being 9.88 +/- 1.80 years were selected. Two standardized lateral cephalometric roentgenographs were taken from all subjects at one year interval. The angular and linear measurements were performed on tracing films. The mean values of these measurements were calculated and statistically evaluated. According to statistical evaluation, the growth and development of the lips and soft tissue chin in both girls and boys were normal and they were in harmony with each other. However in girls the increase of lower lip thickness and in boys the changes of hard and soft tissue pogonion positions were found to be statistically insignificant. In girls, the correlations between the upper lip position and maxillary growth.

Cephalometry↗
PubMed1989

[The vertical changes of orthodontic area with treatment and retention in extraction cases].

The purpose of this study is to determine the vertical changes of orthodontic area during active orthodontic treatment and retention. 10 subjects with Angle class I malocclusion having mean skeletal age of 14 years 3 months were examined. After extraction of first premolars, orthodontic treatments were performed at a mean period of 17.6 months by using "Modified Edgewise Technique"; the Hawley Retainers were used during the retention period for 16.8 months after the active orthodontic treatment. 10 subjects with normal occlusion having mean age 13 years 11 months and 10 subjects with normal occlusion having mean age 15 years 6 months were separated as control groups.

Adolescent↗
PubMed1989

[Effect of topical fluoride treatment on the tensile bond strength of an orthodontic bonding resin].

A study was undertaken to determine the effect of an acidic phosphate fluoride solution (% 2 NaF in 0.1 M H3 PO4, PH3) and a basic phosphate fluoride solution (10(-2) M Na3 PO4 + 10(3) ppm F-, PH 8) on the tensile bond strength of an orthodontic bonding resin (3 M Consise System) soon after application of the pre-bonding etch. 24 premolars were evenly divided into three groups and % 37 orthophosphoric acid was applied to all enamel surfaces for 3 minute to simulate the pre-bonding etch; on the first group of teeth which served as control, brackets were bonded directly to etched surfaces with a Bis-GMA direct bonding adhesive; second group of teeth were received a 1.5 minute application of acidic phosphate fluoride solution and the brackets were bonded directly; third group of teeth were also received a 2.5 minute application of basic phosphate fluoride solution and brackets were bonded directly too.

Acid Etching, Dental↗
PubMed1989

[The changes in orthodontic area after retention period in skeletal Class 2 cases treated with activator].

The aim of this study is to investigate the stability of the results obtained through functional orthodontic treatments after the retention period in skeletal class 2 cases. 14 subjects having skeletal class 2 structures with a skeletal age of approximately 11 years were examined. 7 out of 14 were separated as treatment group, where the other 7 were separated as the control group. Contantion treatment was performed to the treatment group, for a period of 2 years in average, which have been treated with activators for approximately 1 year. The cephalometric radiographs of all subjects were taken at the beginning and the end of treatment and retention. The measurements relating to cephalometric tracing were statistically evaluated.

Activator Appliances↗
PubMed1989

[Effects of activator and activator + anterior high-pull headgear on the growth direction of Class 2 cases].

In this study which the effects of activator and activator + anterior high-pull headgear on the growth direction of skeletal class 2 cases for a period of approximately 9 months; 33 cases having a mean age of 10.59 years; ANB angles 4.5 degrees and over were studied. Activator treatment has been applied to the 11 of the 22 treatment cases, the others have had the activator + anterior high-pull headgear treatment. The control group, 11 patients, has only been observed in terms of the growth and development without having any treatment. At the end of the study; it was found that the decrease in ANB angle and the increase in SL dimension in the treatment groups; the increase in anterior lower face height in the activator group and the increase in the ratio of posterior to anterior face height were statistically significant.

Activator Appliances↗