Comparison of the soft and hard tissue effects of two different protraction mechanisms in class III patients: a randomized clinical trial.

OBJECTIVE: The objective of the present study is to test the null hypotheses that there were no significant differences for hard and soft tissue changes induced by mini maxillary protractor (MMP) and face mask and rapid maxillary expansion (FM/RME). MATERIALS AND METHODS: Thirty-two patients who met the criteria were randomly divided into two groups: 16 patients (males/females 7/9) in the MMP group and 16 patients (males/females 6/10) in the FM/RME group. The patients in both groups were instructed to wear the appliances for at least 20 h per day until a 2-mm positive overjet was achieved. Hard and soft tissue profile changes observed by MMP and FM/RME were compared using paired and Student's t tests. RESULTS: Class III malocclusion and negative overjet were improved by means of skeletal changes in conjunction with upper incisor proclination and lower incisor retroclination in both groups. Maxilla and surrounding soft tissues (SNA, Ls-E, and Ls-PMV) were significantly moved anteriorly with less rotation of the palatal plane in the MMP group. Mandibular incisors were found to be more retrusive in the FM/RME group (p = 0.024). CONCLUSION: Both groups showed similar effects except more anterior movement of the maxilla and surrounding soft tissues with less rotation of the palatal plane and retrusion of lower incisors in the MMP group. CLINICAL RELEVANCE: This is the first study to compare the soft and hard tissue changes induced by MMP appliance with a conventional FM /RME.

The effects of face mask therapy with and without rapid maxillary expansion in adolescent patients.

OBJECTIVE: To examine the effects of face mask therapy with and without associated rapid maxillary expansion (RME) in adolescent patients presenting with skeletal Class III malocclusion characterised by maxillary retrognathism. METHODS: Case records consisting of lateral cephalograms and hand-wrist films of 43 patients with hypoplastic maxillary Class III malocclusions treated using a face mask with and without an RME were analysed. The patients were divided into two groups; Group A (N = 27) were treated with a face mask coupled with rapid maxillary expansion and patients in Group B (N = 16) were treated with a face mask appliance only. Ten cephalometric linear and 9 angular variables were measured to assess the dentofacial changes. Within group and between groups comparisons were determined by a paired t-test and Student's t-test, respectively. RESULTS: Forward displacement of the maxilla and a clockwise rotation of the mandible occurred in both groups. The maxillary-mandibular relationship improved and soft-tissue changes resulted in a more convex profile. The maxillary incisors moved forward only in Group B subjects but the mandibular incisors moved backward in both groups. CONCLUSIONS: Face mask therapy with and without an associated RME improved skeletal Class III malocclusion by a combination of skeletal and dental changes. These results suggested that the use of an RME should be based on clinical criteria rather than assisting the Class III correction.

Changes in soft tissue profile and electromyographic activity after activator treatment.

BACKGROUND: To date, few studies have correlated the changes in muscle activity and specific soft tissue variables in adolescents with malocclusions. OBJECTIVE: To determine associations between the soft tissue profile and electromyographic activities in temporalis, masseter and orbicularis oris muscles in children with Class II division 1 malocclusions treated with activators. METHODS: For this prospective study, 25 subjects with Class II division 1 malocclusions were randomly assigned to either a Treatment group (N=15) or a Control group (N=10). The mean skeletal ages of the subjects in the Treatment and Control groups were 11.3 +/- 1.1 and 11.0 +/- 1.3 years, respectively. The subjects in the Treatment group were treated with activators and the subjects in the Control group were untreated. Lateral cephalometric radiographs and EMG recordings of the anterior temporalis and masseter muscles during clenching, chewing and swallowing and the orbicularis oris muscle during whistling were obtained at the start of the study and 12 months later. Changes in the soft tissue profile were correlated with changes in the EMG activities in anterior temporalis, superficial masseter and orbicularis oris muscles. RESULTS: The upper lip to E line distance (UL-E) decreased more in the Treatment group than the Control group (p < 0.05) and the H angle decreased in the Treatment group, but increased in the Control group (p < 0.01). The EMG activities of temporalis and masseter muscles increased significantly in both groups. All between-group EMG differences were statistically significant with the exception of the activities in the temporalis and masseter muscles during swallowing. In the Treatment group, a significant positive correlation (r = .57) was found between the changes in UL-E and anterior temporalis activity during swallowing, and significant negative correlations were observed between the EMG activity of masseter muscle during swallowing and changes in LL-E (r = -.54), OLp-UL (r = -.55) and OLp-LL (r = -.67). CONCLUSIONS: Activator therapy is accompanied by changes in the lips and temporalis and masseter activities during swallowing.

Effects of early unilateral first molar extraction on skeletal asymmetry.

INTRODUCTION: The purpose of this study was to investigate dental and skeletal asymmetry in patients who had unilateral first molar extractions. METHODS: Two study groups were formed according to the location of the extracted first molars. Group I included 25 subjects who had a maxillary permanent first molar extracted (mean age, 18.25 years). Group II included 26 subjects who had a mandibular permanent first molar extracted (mean age, 17.75 years). The control group included 30 subjects with no missing teeth and normal occlusion (mean age, 18.50 years). Dental and skeletal asymmetry values were computed on posteroanterior radiographs for all subjects. Data were analyzed statistically with paired t tests to determine intragroup differences and with ANOVA and Scheffé tests to determine intergroup differences. RESULTS: Unilateral first molar extractions caused dental midline deviations in both arches, but this was more prominent in the mandibular arch. Unilateral first molar extraction during growth and development can result in remarkable skeletal asymmetry, especially in the lower third of face. CONCLUSIONS: Patients who had early unilateral first molar extraction can have skeletal and dental asymmetries.

Effects of semirapid maxillary expansion on conductive hearing loss.

INTRODUCTION: Conductive hearing loss is affected by physical changes imposed on the mechanical system of the outer or middle ear. Maxillary expansion can affect conductive hearing loss, and the changes have been investigated with pure-tone audiograms. Semirapid and slow methods of maxillary expansion have some advantages over rapid maxillary expansion, but the effects on conductive hearing loss have not been investigated. The purpose of this study was to investigate long-term effects of semirapid maxillary expansion (SRME) with an acrylic bonded appliance on conductive hearing loss by using audiometric and tympanometric records. METHODS: The effects of SRME with a bonded appliance were studied in 19 growing subjects who had narrow maxillary arches and conductive hearing loss. Hearing levels were determined with pure-tone audiometric and tympanometric records. Four records were taken from each subject. The first records were taken before SRME, the second after maxillary expansion (mean, 3.4 months later), the third after retention (mean, 6 months later), and the fourth after fixed-appliance treatment (approximately 2 years later). The data were analyzed with ANOVA. The least-significant difference test was also used to determine when the changes in the measurements were significant. RESULTS: Hearing improved and air-bone gaps decreased at a statistically significant level after active expansion, and these changes remained relatively stable during the last 2 periods. Middle-ear volume increased at a statistically significant level after maxillary expansion and continued to increase until the end of treatment. No significant change was observed in the static compliance value. CONCLUSIONS: SRME treatment has a positive and statistically significant effect on both hearing and normal functioning of the eustachian tubes in patients with transverse maxillary deficiency and conductive hearing loss.

Effects of rapid maxillary expansion on Holdaway soft tissue measurements.

The objective of the present study was to evaluate short-term soft tissue changes caused by rapid maxillary expansion (RME) in 18 subjects (15 females and 3 males) (mean age 13 years 6 months) with a bilateral posterior crossbite. Lateral cephalograms of the patients were obtained at three different time points: before RME (T1), after maxillary expansion (mean = 0.82 month) (T2), and after retention (mean = 5.95 months) (T3). Holdaway soft tissue measurements were used for the evaluation of soft tissue changes. Data were analysed statistically by means of paired t-tests. The facial soft tissue angle decreased (P < 0.05), and H angle and skeletal profile convexity increased significantly (P < 0.001) at T2. During T3, the increase in the facial soft tissue angle and the decrease in H angle were minimal and not significant, while skeletal profile convexity significantly decreased (P < 0.001). The results of this study indicate that RME may affect Holdaway soft tissue measurements.

Heritability of facial proportions and soft-tissue profile characteristics in Turkish Anatolian siblings.

INTRODUCTION: The purpose of this study was to determine the possible effects of genetic factors on facial proportions and soft-tissue profile characteristics in Turkish Anatolian siblings. METHODS: The material consisted of lateral and posteroanterior cephalometric head radiographs of 138 siblings (70 women, 68 men) living 15 years or more in the province of Erzurum in eastern Turkey. The subjects were required to have completed their pubertal growth spurts and to have received no previous orthodontic or prosthodontic treatment. The heritability assessments of craniofacial and soft-tissue measurements were undertaken according to narrow-sense heritability. For the calculation and evaluation of heritability estimate values, the mixed-model least-squared and maximum likelihood computer program model type II was used for statistical analysis. RESULTS: According to the narrow-sense heritability estimate values, the measurements of total depth index, soft-tissue chin thickness, soft-tissue facial angle, Merrifield angle, and Holdaway angle showed the highest heritability coefficients (P <.001). Total height index, anterior height index, facial width index, upper to lower facial height index, and lower lip-E line measurements demonstrated moderate heritability values (P<.01). The upper depth index had a low but statistically significant heritability value (P <.05). However, no statistically significant heritability coefficient in upper lip-E line measurement was found. CONCLUSIONS: Turkish Anatolian siblings have similar facial features regarding facial proportions and soft-tissue measurements.

Effects of face mask treatment with and without rapid maxillary expansion in young adult subjects.

OBJECTIVES: To investigate the skeletal, dental, and soft tissue effects of the face mask (FM) treatment with and without rapid maxillary expansion (RME) in young adult subjects with maxillary retrognathia. MATERIALS AND METHODS: Pretreatment and posttreatment cephalometric radiographs from 32 subjects who had a skeletal Class III malocclusion were analyzed. The subjects were divided into two groups: FM group (N  =  17; 3 male and 14 female subjects; mean [SD] age 14.47 [0.89] years) was treated with FM only, while the RME+FM group (N  =  15; 3 male and 12 female subjects; mean [SD] age 14.67 [1.28] years) was treated with both FM and RME. Ten cephalometric linear and nine angular variables were measured to assess dentofacial changes. Within-group and between-group comparisons were determined by a paired t-test and Student's t-test, respectively. RESULTS: Forward displacement of the maxilla and a clockwise rotation of the mandible occurred in both groups. The maxillary-mandibular relationship improved and soft tissue changes resulted in a more convex profile. The maxillary incisors were more proclined in the FM group than in the RME+FM group, the only difference between the two groups. Notably, the mandibular incisors moved backward in both groups. CONCLUSIONS: Forward movement of the maxilla can be obtained in young adults after face mask treatment. However, there was no difference in this phenomenon between the FM and RME+FM groups.

Histopathologic investigation of the effects of prostaglandin E2 administered by different methods on tooth movement and bone metabolism.

OBJECTIVE: The aim of this study was to investigate and compare the in vivo effects of prostaglandin E2 (PGE2) administered by different methods on orthodontic tooth movement and bone metabolism macroscopically, histopatologically, and biochemically. METHODS: Forty-five young adult New Zealand rabbits were randomly divided into 3 experimental groups (n = 10/group), 1 positive control group (n = 10), and 1 negative control group (n = 5). The experimental rabbits were fitted with springs exerting 20-g reciprocal force on the maxillary incisors and PGE2 (10 µg/mL) was administered by the intravenous, submucosal, or intraligamentous route after appliance insertion and on days 1, 3, 7, and 14 thereafter. All rabbits were sacrificed on day 21 and their premaxillae were resected for histologic evaluation. RESULTS: Tooth movement was observed in the experimental and positive control groups, but the intraligamentous PGE2 group had the highest values of all analyzed parameters, including serum calcium and phosphorus levels and osteoclastic and osteoblastic populations (p < 0.001). CONCLUSIONS: Submucosal and intraligamentous PGE2 administration significantly increases orthodontic tooth movement and bone metabolism, but the intraligamentous route seems to be more effective.

Bone age assessment: the applicability of the Greulich-Pyle method in eastern Turkish children.

The aim of this study was to investigate whether or not the Greulich-Pyle (GP) method is adequate for Turkish children. A group of 767 individuals (425 girls and 342 boys) between 7 and 17 years were studied. Bone age (BA) from plain radiographs of left hands and wrists by GP standards was estimated. The total mean differences between BA and chronological age (CA) for girls and boys were found to be 0.20 and -0.13 years, respectively. There were significant differences between BA and CA in age groups 7-, 8-, 10-, 11-, 12-, 13-, 15-, and 16-year-olds for girls and 7-, 10-, and 12-year-olds for boys. The results of this study suggest that the mean differences between BA and CA are low enough to be of no practical significance, and thus, for the time being unless any other methods will be proved more useful, this method could be used in all age groups.