Dentoskeletal Effects of Multi P® Prefabricated Functional Appliance on Class II Div I Children in Late Mixed Dentition

Objectives: Prefabricated functional appliances have therapeutic effects similar to those of custom-made functional appliances. This study aimed to assess the dentoskeletal effects of Multi P® prefabricated functional appliance on Class II Div 1children in late mixed dentition.Methods: This open label trial was conducted on 18 children aged 9-12 years with Cl II Div 1 malocclusion due to mandibular deficiency during a 9-month period. Written informed consent was obtained from the parents. Multi P ® (RMO, Strasbourg, France) was used by the patients 4 hours/day and overnight (minimum of 8 hours) in conjunction with specific exercises (pressing the teeth in the recorded occlusion, pressing the tongue against the palate and uninostril breathing). Patients were visited monthly. Study casts and cephalometric radiographs were obtained before and after the treatment. Data were analyzed using paired samples t-test and McNemar’s test.Results: The Go-Gn (P=0.029) and Me-N (P=0.021) distances significantly increased following the use of appliance while overjet (P<0.0001), absolute overbite (P=0.002) and the Wits appraisal (P=0.019) significantly decreased. Other understudy angles did not change significantly.Conclusion: Multi P® appliance decreases the jaw base discrepancy and corrects the overjet and overbite

Evaluation of Oxygen Saturation by Pulse-Oximetry in Mouth Breathing Patients

Mouth breathing might not always result in hypoxia, but can contribute to it. The aim of the present study was to determine the effect of mouth breathing on hypoxia. Based on a pilot study, 323 patients with mouth breathing were selected. Assessment of mouth breathing was based on clinical examination and questionnaires filled out by patients and their companions. The patients were also examined for further oral findings that could be attributable to mouth breathing. Oxygen saturation of each case was measured by means of a pulse oximetry device. The level of 95% saturation was set as the limit, under which the patient was considered hypoxemic. Acquired data was analyzed for descriptive data and frequency and also by means of the Chi-square and Spearman’s correlation coefficient tests.  34.6% of the cases had normal O2 saturation. 65.4% of cases were hypoxemic (saturation level was below 95% in 42.8% and 95% in 22.6%). Most of the mouth breathing patients were male who were also more hypoxemic.  A weak inverse relationship existed between the age of the patients and Oxygen saturation. Deep palatal vaults (29.4%) and gingival hyperplasia (29.2%) were the most frequent intraoral findings. Concerning the effects of hypoxia on body systems, the use of pulse oximetry in suspected mouth breathing patients could be recommended in routine oral and dental examinations

Designing Orthodontic Craniofacial Templates for 8-14 year-old Iranian Girls Based on Cephalometric Norms

Objectives: Cephalometry and its related analyses have an important role in the evaluation of orthodontic patients. Access to an analysis that gives maximum information in the least possible time is an effective way to indicate craniofacial disharmony; therefore, craniofacial templates are very useful tools. The purpose of the present study was to provide orthodontic craniofacial templates for 8-14-year-old Iranian girls.Materials and Methods: One thousand two-hundred and nine girls (age range, 8-14 years) were examined. Eighty of these cases were finally chosen for the study and their lateral cephalograms were traced. Both Basion-Nasion (Ba-N) and Sella-Nasion (S-N) lines were selected for superimposition in this study. Based on these two mentioned lines, a template for each age was designed. Simple linear regression and multivariant regression analysis were used to evaluate the angles and to landmark the vectors, respectively.Results: Findings show that most points change significantly at different ages in the S-N method. In the Ba-N method, all points except for S and Ba have significant changes at different ages.Conclusion: Templates that resulted from both methods were the same and alteration in the reference line and points does not change the total form of the average tracings of each age

Evaluation of Shear Bond Strength of Orthodontic Brackets Bonded with Nano-filled Composites

Objectives: The purpose of this study was to evaluate the shear bond strength (SBS) of orthodontic brackets bonded with two types of nano-composites in comparison to a conventional orthodontic composite. Materials and Methods: Sixty extracted human first premolars were randomly divided into 3 groups each containing 20 teeth. In group I, a conventional orthodontic composite (Transbond XT) was used to bond the brackets, while two nano-composites (Filtek TM Supreme XT and AELITE Aesthetic Enamel) were used in groups II and III respectively. The teeth were stored in distilled water at 37°C for 24 hours, thermocycled in distilled water and debonded with a universal testing machine at a crosshead speed of 1 mm/min. The adhesive remnant index (ARI) was also evaluated using a stereomicroscope. Results: AELITE Aesthetic Enamel nano-composite revealed a SBS value of 8.44±2.09 MPa, which was higher than Transbond XT (6.91± 2.13) and Filtek TM Supreme XT (6.04± 2.01). Statistical analysis revealed a significant difference between groups II and III (P < 0.05). No significant difference was found between groups I and III, and between groups I and II (P > 0.05). Evaluation of ARI showed that Transbond XT left fewer adhesive remains on teeth after debonding. Conclusion: Results of this study indicate that the aforementioned nano-composites can be successfully used for bonding orthodontic brackets

Effect of Adhesive Type on the Shear Bond Strength of Metal Brackets to Two Ceramic Substrates

Increased number of adult patients requesting orthodontic treatment result in bonding bracket to ceramic restorations more than before. The aim of this study was to evaluate and compare the shear bond strength of orthodontic brackets bonded to two types of ceramic bases with conventional orthodontic bonding resin and a new nano-filled composite resin.Twenty four feldespathic porcelain and 24 lithium disilicate ceramic disks were fabricated. All of the samples were conditioned by sandblasting, hydrofluoric acid and silane. Maxillary incisor metal brackets were bonded to half of the disks in each group by conventional orthodontic bonding resin and the other half bonded with a nano-filled composite. The samples then were thermocycled for 2000 cycle between 5-55° C. Shear bond strength was measured and the mode of failure was examined. Randomly selected samples were also evaluated by SEM.The lowest bond strength value was found infeldespathic ceramic bonded by nano-filled composite (p<0.05). There was not any statistically significant difference between other groups regarding bond strength. The mode of failure in the all groups except group 1 was cohesive and porcelain damages were detected.Since less damages to feldspathic porcelain was observed when the nano-filled composite was used to bond brackets, the use of nano-filled composite resins can be suggested for bonding brackets to feldspathic porcelain restorations

Cephalometric evaluation of tongue position and oropharynx space in children treated with Twin-block appliance

Background and Aims: Functional therapy locates the mandible in a more anterior and inferior position. Tongue posture and oropharynx space have a considerable relationship with mandibular posture. The aim of the present study was to determine the changes of tongue posture and oropharynx space following treatment with Twin block appliance in adolescent patients with class II division 1 ma1occlusion. Materials and Methods: Twenty two patients (14 girls mean age:11.5, 8 boys mean age:12.5 years) who were treated with twin-block appliance were enrolled. Cephalograms were used to assess the linear measurements. Graber pattern and McNamara parameter were used to evaluate the tongue posture and oropharynx space, respectively. Data analysis was performed by paired t-test. Results: The findings of the present study showed a significant increase in anterior position of tongue (P=0.06). Oropharynx space was increased significantly (P<0.001). There was a significant correlation between the decrease of ANB and anteroposterior increase of oropharynx space. Conclusion: Twin-block appliance caused considerable forward movement of tongue and significant increase of oropharynx space in the sagittal plan

Face Vertical Dimension Change and Incisors Position Following Orthodontic Treatment with Extraction of Four First Premolars

Introduction: The aim of this study was to evaluate vertical dimension of face and position of incisors following extraction of four first premolars in patients with class I malocclusion and bimaxillary dentoalveolar protrusion and/or crowding. Materials and Methods: This study evaluated 22 patients with class I molar relationship, bimaxillary dentoalveolar protrusion and/or crowding with the treatment plan of extraction of all four first premolars. The change in U1-PP, L1-MP, IMPA, U1-SN, saddle angle, articular angle, gonial angle, and the sum of Bjork was determined by assessing the before and after-treatment cephalograms. The changes in cephalometric parameters were analyzed by ANOVA and paired t-test. Results: The U1-SN, IMPA, U1-PP and sum of Bjork significantly changed following extraction of the four first premolars (P&lt;0.05). However, the changes in saddle, articular and gonial angles and L1-MP were not significant (P&gt;0.05). Conclusion: We observed retraction and extrusion of incisors and increase of vertical dimension following extraction. Retraction of incisors will relatively retract lips. Also, it is not advisable to extract premolars to improve vertical dimension, although extrusion of incisors will facilitate the bite closure

Two-Dimensional Analysis of the Size of Nasopharynx and Adenoids in Non-Syndromic Unilateral Cleft Lip and Palate Patients Using Lateral Cephalograms

Objectives: Cleft lip and palate (CLP) is the most common congenital anomaly of the head and neck region. The upper airway in CLP patients is affected by retarded maxillary growth. Small size of the nasopharynx can also lead to mouth breathing. This study aimed to compare the size of nasopharynx and adenoids in non-syndromic unilateral CLP (NSUCLP) patients and healthy controls two-dimensionally on lateral cephalograms. Materials and Methods: This retrospective study was performed on 30 children with NSUCLP (mean age of 11.3 years) and 30 sex- and age-matched healthy controls with class I skeletal relationship. The bony boundaries of the nasopharynx, nasopharyngeal airway and adenoids were outlined on lateral cephalograms and their surface area was calculated and compared between the two groups. The percentage of nasopharynx occupied by the adenoids was calculated for each individual and compared between the two groups using independent t-test. Results: Size of nasopharynx in NSUCLP children was significantly smaller than that in healthy controls (P=0.0001). Size of adenoids was significantly larger in NSUCLP children (P=0.0001). Size of nasopharyngeal airway was smaller in NSUCLP patients than controls (P=0.0001). Percentage of nasopharynx occupied by the adenoids was significantly greater in NSUCLP patients (P=0.0001). Conclusions: The size of nasopharynx is smaller while the size of adenoids is larger in NSUCLP children compared to healthy controls; this can lead to mouth breathing and velopharyngeal incompetence

Comparison of Bond Strength of Metal and Ceramic Brackets Bonded with Conventional and High-Power LED Light Curing Units

Objectives: The aim of this study was to evaluate the effect of conventional and high-power light emitting diode (LED) light curing units on shear bond strength (SBS) of metal and ceramic brackets to tooth surface. Materials and Methods: Forty sound bovine maxillary central incisors were used for the study. The teeth were divided into four groups (n=10). Teeth surfaces were etched with 37% phosphoric acid for 20 seconds. After applying a uniform layer of adhesive primer on the etched enamel, composite was placed on the base of brackets. The samples were light cured according to the manufacturer’s instructions and thermocycled. The SBS was measured. The failure mode was scored using the adhesive remnant index (ARI). Results: The mean SBS of samples in groups A (high-power LED, metal bracket), B (high-power LED, ceramic bracket), C (conventional LED, metal bracket) and D (conventional LED, ceramic bracket) was 23.1±3.69, 10.7±2.06, 24.92±6.37 and 10.74±3.18MPa, respectively. The interaction effect of type of LED unit (high-power/conventional) and bracket type on SBS was not statistically significant (P=0.483). In general, type of LED unit did not affect SBS. Type of bracket significantly affected SBS (P<0.001). The ARI score was not significantly influenced by the interaction between the type of LED unit and bracket. Conclusions: The obtained SBS is the same for both bracket types by use of high-power and conventional LED light curing units. Regardless of the type of LED unit, SBS of ceramic brackets was significantly lower than that of metal brackets.