Correlation of alveolar bone thickness and central incisor inclination in skeletal Class I and II malocclusions with different vertical skeletal patterns: A CBCT study

INTRODUCTION

This study aimed to assess the alveolar bone thickness (ABT) and labiolingual inclination of maxillary and mandibular central incisors in patients with Class I and II skeletal patterns with normal-angle, high-angle, and low-angle vertical patterns.

METHODS

The study sample consisted of 200 cone-beam computed tomography scans of patients with skeletal Class I and II malocclusions. Each group was further divided into low-angle, normal-angle, and high-angle subgroups. Labiolingual inclinations of maxillary and mandibular central incisors and ABT were measured at 4 levels from the cementoenamel junction in the labial and lingual surfaces. The Kolmogorov-Smirnov test, independent t test, 2-way analysis of variance, and Spearman's correlation test were applied for statistical analyses.

RESULTS

The only significant difference between Class I and II groups regarding the ABT was found at the labial side of the maxillary central incisor, 9 mm apical to the crest. At this level, the mean ABT was 0.87 mm in patients with a skeletal Class I malocclusion, which was significantly greater than that in patients with a skeletal Class II malocclusion with a mean ABT of 0.66 mm (P = 0.02). Comparisons among the vertical subgroups revealed that on the labial and lingual sides of the mandible, as well as the palatal side of the maxilla, significantly thinner alveolar bone was found in patients with high-angle growth patterns than those with normal-angle and low-angle patterns in both sagittal groups (P <0.05). Significant weak to moderate correlations were found between ABT and tooth inclination (P <0.05).

CONCLUSIONS

Significant differences in ABT covering central incisors between patients with skeletal Class I and II malocclusion are merely observed at the labial surface of the maxilla, 9 mm apical to the cementoenamel junction. Compared with patients with normal-angle and low-angle, those with a high-angle growth pattern and Class I and II sagittal relationships have thinner alveolar bone support around maxillary and mandibular incisors.

Estimating and comparing the duration of adolescent growth peak in skeletal class I and III subjects using cervical vertebral maturation method

Background

Estimating skeletal maturation and growth potential is essential for developing adolescents' best orthodontic treatment plan. The purpose of this study was to compare the duration of adolescent growth peak in subjects of skeletal classes I and III using the cervical vertebral maturation (CVM) method.

Methods

This retrospective cross-sectional study included 116 Iranian subjects (skeletal class I = 68, skeletal class III = 48) aged 8–16 years old and without previous orthodontic treatments. Using Steiner and Wits analyses, two independent examiners traced pre-treatment lateral cephalograms to determine the subjects' skeletal relationship. The skeletal maturation was then assessed using Baccetti's CVM method. The onset and duration of adolescent growth peak (interval of CS3–CS4) were compared between two skeletal classes and two genders using independent samples t test.

Results

In skeletal class I and III subjects, the adolescent peak had a mean duration of 1.62 (± 1.33) and 2.00 (± 1.27) years, respectively. The average difference of 0.38 years (4.6 months) between the two groups was statistically significant (p < 0.001). Furthermore, the onset age of adolescent growth peak was 11.91 (± 1.32) and 12.08 (± 1.31) years old in class I and III subjects, respectively. This age difference was not statistically significant (p = 0.630). Males’ adolescent growth peak occurred 1.44 years later (p < 0.001) and lasted 0.20 years less (p < 0.001).

Conclusions

The adolescent growth peak started at a similar age in class I and III subjects, but the latter experienced the peak for 4.6 months longer. Moreover, females had an earlier and more extended adolescent growth peak.

The correlation between external apical root resorption and electric pulp test responses: a prospective clinical trial

OBJECTIVE

The current study investigated the correlation between pulpal sensitivity to the electric pulp tester (EPT) and external apical root resorption (EARR) in four types of maxillary anterior teeth of fixed orthodontic treatment patients.

METHODS

In this prospective cohort study, 232 anterior teeth of 58 patients (mean age 18.96 ± 6.13 years) treated with fixed orthodontic treatment were examined. The EPT readings were recorded at twelve time points immediately before archwire insertion. Root resorption of four maxillary incisors were measured by means of parallel periapical radiographs at three time intervals (six months interval from the start) through design-to-purpose software to optimize data collection. A multiple linear regression model and Pearson correlation coefficient were used to assess the association of EPT values and observed EARR (p< 0.05).

RESULTS

The highest level of EPT measurement was recorded at initial visit, and then there was a decreasing trend in EPT level during treatment for the next six and twelve months. There was another increasing trend after six months till the finishing time of the treatment. There was a significant correlation between changes in root length and time of recording the root length (p< 0.001). There was significant positive correlation between changes in EPT level and amount of observed root resorption (p< 0.001).

CONCLUSION

The relative decrease in electric pulp test level could be a diagnostic sign of root resorption during orthodontic treatment. Further studies with longer follow up are needed to confirm the current results.

The impact of platelet-rich fibrin (PRF) on delayed tooth replantation: A preliminary animal study

The aim of this study was to evaluate the effect of platelet-rich fibrin (PRF) placed in delayed replantation of mature extracted teeth. Sixteen intentionally extracted teeth in two mature beagle dogs were selected. In one quadrant of each jaw, the extraction sockets were filled with PRF prior to replantation, and the other quadrant served as control without PRF. All extracted teeth underwent endodontic treatment and dried for 60 min. Thereafter, they were replanted with a flexible splint. After 8 weeks, the animals were euthanised, and the histological sections examined. Less inflammatory root resorption was noted in the PRF group compared to the control (P = 0.031). However, there was no significant difference between the two groups with regard to new bone formation, inflammatory status, connective tissue healing and replacement resorption (P > 0.05). Using PRF in the extracted socket before delayed replantation did not provide any significant benefit other than reduced inflammatory root resorption.

Relationship of the rs10850110 and rs11611277 polymorphisms of the MYO1H gene with non-syndromic mandibular prognathism in the Iranian population

BACKGROUND

The myosin 1H (MYO1H) gene, located on chromosome 12, encodes the unconventional MYO1H protein, which is involved in the intracellular movement and morphology of chondrocytes, and plays a vital role in the prognathism or retrognathism of the mandible.

OBJECTIVES

The objective of this study was to assess the relationship between the polymorphisms of the MYO1H gene and mandibular prognathism in the Iranian population.

MATERIAL AND METHODS

The current project evaluated 64 patients with mandibular prognathism requiring orthognathic surgery and 60 controls with skeletal class I occlusion. Genome amplification was performed using specific primer pairs to assess the rs10850110 and rs11611277 polymorphisms of the MYO1H gene through the polymerase chain reaction (PCR). The restriction fragment length polymorphism (RFLP) technique was used to detect single-nucleotide polymorphisms. The data was analyzed using the χ2 test.

RESULTS

The patient and control groups were not significantly different in terms of age or gender (p > 0.05). In all, 3.1% of patients and 6.7% of controls had the rs10850110 polymorphism (p = 0.680), and 1.6% of patients and 5% of controls had the rs11611277 polymorphism (p = 0.602).

CONCLUSIONS

No significant correlation was noted between the rs10850110 and rs11611277 polymorphisms of the MYO1H gene and mandibular prognathism in the Iranian population. However, the lower frequency of these polymorphisms in the patient group suggests a possible association with mandibular retrognathism, which needs to be investigated with a larger sample size.

Correlation assessment of cervical vertebrae maturation stage and mid-palatal suture maturation in an Iranian population

AIM

The aim of the current study was to evaluate the correlation of skeletal age based on cervical vertebrae maturation (CVM) stage and mid-palatal suture (MPS) maturation in an Iranian population.

MATERIAL AND METHODS

This was a cross-sectional analytic study. A total number of 93 samples were included. Samples were taken from patients who were in CS3 to CS6 stages of CVM who had cone-beam computed tomography and lateral cephalometry based on inclusion criteria. The maturation of MPS was assessed based on the cone-beam computed tomography images. In the classification of maturation of MPS, there are five stages (A-E) and the suture fusion occurs in stage D. In stage E, the suture is fused completely. The CVM stage (CS1-6) was also assessed based on the lateral cephalograms. Data were analyzed using Spearman correlation with a significance level of 0.05.

RESULTS

A total of 51 female individuals with a mean age of 14.98 ± 4.806 and 42 male individuals with a mean age of 15.79 ± 5.135 participated in this study. The correlation coefficient between the CVM stage and MPS maturation was 0.691 in female and 0.754 in male individuals (P < 0.001). Stage D was correlated with CS4.

CONCLUSION

The results demonstrated that CVM stages had a significant but moderate positive correlation with the maturation of MPS. Until CS3, the MPS has not been fused and in CS6 the MPS is fused definitely.

Effect of different debonding techniques on shear bond strength and enamel cracks in simulated clinical set-ups

OBJECTIVE

The aim of this study was to evaluate the relationship between debonding forces and enamel cracks length change between different debonding techniques.

METHODS

80 extracted premolar teeth with intact buccal enamel were divided into five groups. In each group, enamel cracks were evaluated by stereomicroscope before and after debonding. All teeth were bonded with metal brackets by self-cure adhesive (3M, USA) and then debonded by bracket debonding plier, fixed on the UTM machine, through five methods based on location of plier on brackets: OGwing (occlusogingival), MDwing (mesiodistal), Oblique, OGbase (occlusogingival) and Cusp-base.

RESULTS

Based on non-parametric distribution of data, there was no significant difference between groups in ARI and enamel cracks length change. The highest shear bond strength for debonding presented in OG base method (25.25 ± 8.4) and the difference was statistically significant (P-value = 0.029). There was no linear relationship between shear bond strength and cracks length change and also between ARI and cracks length change.

CONCLUSION

Despite the lower cracks length change in Cusp-base method than other groups, there wasn't significant difference between debonding methods. Also the amount of debonding forces and ARI do not affect the changes of cracks length.

Lingual Orthodontic Treatment: Efficacy and Complications

Aims and Objectives:

The high esthetic demands led to the promotion of various esthetic appliances like lingual orthodontics. This study aimed to review clinical outcome and potential complications of lingual orthodontics to achieve an evidence-based decision for orthodontic therapies.

Materials and Methods:

A comprehensive electronic search was conducted from January 1975 to March 2019 which was limited to English language and administrations of lingual orthodontics treatment which evaluated its efficacy and potential complications. Data extraction was performed according to the PRISMA statement.

Results:

49 studies were selected and analyzed in this systematic review. The pain of lingual appliances starts a little earlier and lasts longer, and patients with lingual appliances experience more tongue discomfort and less cheek and lip pain and greater eating difficulties especially after placement and take a longer time to adapt to appliances. Lingual appliances generally cause more plaque accumulation and gingivitis especially in lingual anterior teeth; however, labial appliances are associated with high frequency in posterior maxillary teeth.

Conclusion:

This systematic review shows that despite the drawbacks of these appliances such as pain and eating difficulties, they can accomplish treatment goals with the same outcomes in comparison with conventional approaches, within the same duration and even lesser anchorage loss.

Impact of malocclusion severity on oral health-related quality of life in an Iranian young adult population

Objective:

This study aimed to assess the relationship between malocclusion severity and oral health-related quality of life (QoL) of 18 to 25-year-old Iranians who sought orthodontic treatment.

Materials and Methods:

A total of 126 patients between 18 and 25 years attending some private orthodontic clinics answered the oral health impact profile-14 (OHIP-14) and a demographic questionnaire. Two calibrated orthodontists recorded the Index of Orthodontic Treatment Need-Dental Health Component (IOTN-DHC) determining the severity of malocclusion (Kappa = 0.8). The IOTN-Aesthetic Component (IOTN-AC) was reported by patients for assessing the perception of their esthetic severity of malocclusion. Logistic regression analysis was used. Level of significance was set at α = 0.05.

Results:

The mean score of OHIP-14 was 20.87 ± 8.6. The frequency of patients with no/slight, borderline, and definite need for orthodontic treatment was determined as 13.4%, 23.8%, and 62.7%, respectively, by IOTN-DHC. There were significant correlations between borderline or definite need treatment and OHIP-14 overall score (P < 0.05). Patients with borderline and definite need for orthodontic treatment had 5 and 21 times lower QoL, respectively, than those with a slight need for orthodontic treatment. Based on IOTN-AC, 50.8% of the patients mentioned slight or no need based on IOTN-AC. No significant association was noted between IOTN-AC and OHIP-14 overall scores.

Conclusions:

The results showed negative impact of malocclusion severity on the QoL. This study highlighted the importance of individual assessment of orthodontic patients.

Common conditions associated with displacement of the inferior alveolar nerve canal: A radiographic diagnostic aid

Purpose

This study reviewed the common conditions associated with displacement of inferior alveolar nerve canal.

Materials and Methods

General search engines and specialized databases including Google Scholar, Pub Med, Pub Med Central, Science Direct, and Scopus were used to find relevant studies by using keywords such as “mandibular canal”, “alveolar canal”, “inferior alveolar nerve canal”, “inferior dental canal”, “inferior mandibular canal” and “displacement”.

Results

About 120 articles were found, of which approximately 70 were broadly relevant to the topic. We ultimately included 37 articles that were closely related to the topic of interest. When the data were compiled, the following 8 lesions were found to have a relationship with displacement of mandibular canal: radicular/residual cysts, dentigerous cyst, odontogenic keratocyst, aneurysmal bone cyst, ameloblastoma, central giant cell granuloma, fibrous dysplasis, and cementossifying fibroma.

Conclusion

When clinicians encounter a lesion associated with displaced mandibular canal, they should first consider these entities in the differential diagnosis. This review would help dentists make more accurate diagnoses and develop better treatment plans according to patients' radiographs.

Common conditions associated with mandibular canal widening: A literature review

Purpose

The aim of this study was to review the common conditions associated with mandibular canal widening.

Materials and Methods

General search engines and specialized databases including Google Scholar, PubMed, PubMed Central, Science Direct, and Scopus were used to find relevant studies by using the following keywords: “mandibular canal,” “alveolar canal,” “inferior alveolar nerve canal,” “inferior dental canal,” “inferior mandibular canal,” “widening,” “enlargement,” “distension,” “expansion,” and “dilation.”

Results

In total, 130 articles were found, of which 80 were broadly relevant to the topic. We ultimately included 38 articles that were closely related to the topic of interest. When the data were compiled, the following 7 lesions were found to have a relationship with mandibular canal widening: non-Hodgkin lymphoma, osteosarcoma, schwannoma, neurofibroma, vascular malformation/hemangioma, multiple endocrine neoplasia syndromes, and perineural spreading or invasion.

Conclusion

When clinicians encounter a lesion associated with mandibular canal widening, they should immediately consider these entities in the differential diagnosis. Doing so will help dentists make more accurate diagnoses and develop better treatment plans based on patients' radiographs.

Agreement of the clinician's choice of archwire selection on conventional and virtual models

OBJECTIVES

To compare archwire selection on dental casts with archwire selection using a three-dimensional (3D) software program (OrthoAid) and assess agreement between clinicians.

MATERIALS AND METHODS

The best-fitting archwires were selected for dental casts of 100 patients with malocclusion using two approaches by three orthodontists. The first method was to visually determine the fitness of five preformed nickel titanium archwires to the arch form on a dental cast (subjective method). The second method was archwire selection on a virtual image of the same cast by means of 3D software (objective method). Agreement between selections performed by the orthodontists was calculated using Kappa statistics. The accuracy of fit of the archwires to the curves fitted to the arch form was also calculated or reversely assessed by means of the root mean square (RMS) for both methods using the Dahlberg formula.

RESULTS

The mean RMS of the distances between the patient arch forms and the archwires for the subjective method was 1.163-1.366 mm. The agreement of selections between orthodontists was 42%-58% (Kappa ranged from .074 to .382). Using the 3D software (objective method), the mean RMS decreased to 0.966-1.171 mm, and agreement increased to 47% to 84% (Kappa ranged from .444 to .747).

CONCLUSIONS

The use of 3D computer software for archwire selection in patients with malocclusion provided better adaptation and interexaminer reliability.

Shear bond strength and adhesive remnant index of orthodontic brackets bonded to enamel using adhesive systems mixed with TiO2 nanoparticles

INTRODUCTION

It is recently suggested that titanium dioxide (TiO2) nanoparticles can be added to bracket luting agents in order to reduce bacterial activity and protect the enamel. However, it is not known if this addition can affect the shear bond strength (SBS) below clinically acceptable levels. Therefore, this study examined this matter within a comprehensive setup.

METHODS

This in vitro experimental study was conducted on 120 extracted human premolars randomly divided into four groups (n=30): in groups 1 and 2, Transbond XT light-cured composite with or without TiO2 was applied on bracket base; in groups 3 and 4, Resilience light-cured composite with or without TiO2 was used. Brackets were bonded to teeth. Specimens in each group (n=30) were divided into three subgroups of 10 each; then incubated at 37°C for one day, one month, or three months. The SBS and adhesive remnant index (ARI) were calculated and compared statistically within groups.

RESULTS

The SBS was not significantly different at one day, one month or three months (p>0.05) but composites without TiO2 had a significantly higher mean SBS than composites containing TiO2 (p<0.001). The SBS of Transbond XT was significantly higher than that of Resilience (p<0.001). No significant differences were noted in ARI scores based on the type of composite or addition of TiO2 (p>0.05).

CONCLUSIONS

Addition of TiO2 nanoparticles to Transbond XT decreased its SBS to the level of SBS of Resilience without TiO2; thus, TiO2 nanoparticles may be added to Transbond XT composite for use in the clinical setting.

Cephalometric changes in nasopharyngeal area after anterior maxillary segmental distraction versus Le Fort I osteotomy in patients with cleft lip and palate

OBJECTIVE

The present study was designed to compare the effects of two surgical methods, anterior maxillary segmental distraction (AMSD) versus conventional Le Fort I osteotomy, on cephalometric changes of velopharyngeal area of patients with cleft lip and palate.

MATERIALS AND METHODS

This study was conducted on 20 CLP in two groups. The first group had classic Le Fort I maxillary advancement and the second group had AMSD with a modified hyrax as an intraoral tooth-borne distractor. In the second group, 1 week after the surgery, activation of hyrax screw was started with the rate of 2 times a day for about 10 days. Initial and final lateral cephalograms were traced and analyzed by OrthoSurgerX software.

RESULTS

The changes in variables evaluating velopharyngeal status showed a significant difference between the two groups. In Group A (conventional), the mean of nasopharyngeal area and Nasopharynx floor length showed a significant increase (P < 0.05) after the surgery, while in Group B (DO), the trend of changes was vice-versa. The changes in SNA, overjet, and soft-tissue convexity were similar in both groups.

CONCLUSION

AMSD can improve facial profile, almost similar to the conventional Le Fort I advancement, while there is a significant decrease in nasopharyngeal; hereby there is no increase in the velopharyngeal sphincter.

Tooth-borne distraction osteogenesis versus conventional Le Fort I in maxillary advancement of cleft lip and palate patients

BACKGROUND

Distraction osteogenesis (DO) is rapidly becoming a mainstream surgical technique for correction of maxillary deficiency. The aim of this study was to compare the effectiveness of a newly designed tooth-borne osteogenic distraction device with conventional Le Fort 1 osteotomy in maxillary advancement of cleft lip and palate patients.

METHODS

The DO group consisted of 10 subjects (7 males, 3 females) with a mean age of 21.2 (SD 4.2) years. In these patients, the newly designed distraction device which exerted force anteroposteriorly was cemented after mobilization of the maxilla. After a latency period of 7 days, the distractor was activated twice daily by a total amount of 0.5 mm per day. The activation was continued for 3 weeks. After an 8-week consolidation period, the distraction appliance was removed. Cephalograms of DO patients were obtained at the start of distraction and at the end of consolidation. The Le Fort 1 group consisted of 11 subjects (6 males, 5 females) with a mean age of 22.3 (SD 3.7) years. Pre and postsurgery lateral cephalograms were obtained. t-test and paired t-test were used to evaluate the data.

RESULTS

At the end of treatment, the SNA angle of Le Fort 1 patients increased by 5.5° (SD 2.3) (P<0.001) and the SNA angle of DO patients increased by 3.4° (SD 2) (P<0.001).

CONCLUSIONS

Current evidence suggests that both conventional Le Fort 1 and tooth-borne osteogenic distraction device can effectively advance the maxilla forward in patients with cleft lip.

Effect of Bleaching Mouthwash on Force Decay of Orthodontic Elastomeric Chains

INTRODUCTION

Force decay elastomeric chains are significant, and it is a clinical problem.

AIM

The aim of this study was to evaluate the effects of bleaching agent in the mouthwash on the force decay of orthodontic chains.

MATERIALS AND METHODS

In this experimental study, 160 gray closed elastomeric chains were randomly divided into three groups (one control and two test groups). Four loops of chains were stretched for 25 mm on custom-made jig. Control group specimens were immersed in artificial saliva during the test period. Test group specimens were immersed twice a day for 30 seconds in the whitening (LISTERINE® HEALTHY WHITE™) and daily sodium fluoride (LISTERINE® TOTAL CARE ZERO) mouthwashes. All specimens were immersed in artificial saliva at 37°C. Force was measured at different time points (initial, 1, 7, 14, 21, 28 days). Statistical analysis was performed by two-way analysis of variance (ANOVA) and Bonferroni methods (a = 0.05).

RESULTS

Force of elastomeric chains was decreased dramatically in all groups during the experiment. After 24 hours, force was decreased by 42.18, 48.34, and 53.38% in control group, daily, and bleaching mouthwash groups respectively. The corresponding numbers after 4 weeks were 66.30, 76.73, and 86.48. The difference between three groups at days 1 and 28 was statistically significant (p < 0.05).

CONCLUSION

Within the limitations of the current in vitro study, bleaching and sodium fluoride mouthwashes could cause force decay of orthodontic elastomeric chains. Whitening mouthwash is more weakening for elastomeric chains.

CLINICAL SIGNIFICANCE

Use of whitening mouthwash by orthodontic patients could decrease the force of elastomeric chains, so it could be recommended to use them for a short time.

The effect of toothpastes with bleaching agents on the force decay of elastomeric orthodontic chains

Objective:

The aim of this study was to evaluate the effect of agents available in whitening toothpastes (Crest^® and Sensodyne^®) in vitro on the force decay of elastomeric chains used in orthodontics.

Materials and Methods:

A total of 300 specimens of elastomeric chains were divided into five groups (n = 60) and were evaluated. These groups included (1) the regular Crest® toothpaste and distilled water solution, (2) whitening Crest^® toothpaste and distilled water solution, (3) regular Sensodyne^® toothpaste and distilled water solution, (4) whitening Sensodyne^® toothpaste and distilled water solution, and (5) distilled water as a control group. The samples' force was measured using Instron at intervals of 0, 1, 7, 14, 21, and 28 days. Data were analyzed by SPSS software.

Results:

At the initial time point, the difference in the force values of elastomeric chain between any of the groups was not significant (P > 0.05). On the 1^st day, there was a significant difference (P < 0.05) between all groups except the groups of whitening Crest^®, regular, and whitening Sensodyne^® (P > 0.05). On days 7, 14, and 28, the rate of decline for all groups was statistically significant (P < 0.05).

Conclusions:

According to the results obtained in the present study, it seems that toothpastes without whitening agents have less effect on force decay of elastomeric chain over time.

The short-term effects of face mask and fixed tongue appliance on maxillary deficiency in growing patients--a randomized clinical trial

BACKGROUND

The purpose of this single blind, prospective, parallel randomized trial study was to compare the effects of face mask and fixed tongue appliance in treatment of Class III malocclusion with maxillary deficiency in growing patients.

METHODS

88 patients with maxillary deficiency were selected. 60 fulfilled the study requirements. The patients were randomly assigned to 2 groups by computer generated tables. One group was treated with removable face mask and the other group was treated by fixed tongue appliance. 4 of the patients dropped out of study leaving a final number of 56 patients. Thus, the face mask group included 30 patients (13 males, 17 females) with the mean age of 8.5 (SD 1.4) years and the fixed tongue appliance group included 26 patients (13 males, 13 females) with the mean age of 8.9 (SD 1.7) years. The patients Lateral cephalograms obtained at the beginning and end of the study were analyzed.

RESULTS

Paired t-tests showed that SNA increased by 1.3° (SD 1.1°) in face mask group (P<0.001) and it increased by 1.8° (SD 0.9°) in fixed tongue appliance group (P<0.001). T-test showed that there were no statistically significant differences between the two groups except for SNB. IMPA decreased significantly in both groups.

CONCLUSIONS

Both treatment modalities were successful in moving the maxilla forward and improving the profile of the patients; however, the bulky size of face masks might reduce patients' compliance and make them less favorite choice of treatment.

Treatment of maxillary deficiency by miniplates: a case report

Introduction. Numerous devices have been introduced for correction of Class III malocclusion and maxillary deficiency. Aim. To assess the dentoskeletal effects of miniplates combined with Class III traction in treating Cl III malocclusion and maxillary deficiency in growing patients. Methods. This case describes the treatment of a maxillary-deficient 11-year-old boy by using miniplates. The patient's parents rejected the use of extraoral appliances and major surgical correction; therefore the treatment was done by using Class III elastics connected from two mandibular miniplates to an upper removable appliance. Two miniplates were inserted in the anterior part of the mandible in the canine areas under local anaesthesia. The treatment lasted for 10 months after which favourable correction of the malocclusion was observed. Results. The SNA and ANB angles increased by 5.1° and 4.4°, respectively. Lower 1 to mandibular plane decreased by 3.4°. Conclusions. This case demonstrates that miniplates can be a suitable method to extraoral appliances and major surgery in maxillary deficiency cases.

Strength of attachment between band and glass ionomer cement

AIM

To determine the strength of attachment between plain stainless steel band material and glass ionomer cement.

METHODS

Seventy-five extracted upper premolars, free of visible structural defects, were used. The teeth were divided randomly into three groups and embedded in acrylic resin blocks. A short length of plain, stainless steel band material with a welded stainless steel standard edgewise 0.022 inch bracket was adapted to the buccal surface of each tooth. The bracket-stainless steel pads were then cemented to the teeth with either Bandtite (Group 1), Granitec (Group 2) or Ariadent (Group 3) glass ionomer cement and stored in an incubator at 37 degrees C for 30 days. The shear bond strengths of the specimens were measured and compared.

RESULTS

The mean shear bond strengths (SBS) were significantly different: Bandtite 0.7331 +/- 0.056 Mpa; Granitec 0.3869 +/- 0.047 Mpa; Ariadent 0.2931 +/- 0.033 Mpa (ANOVA, p < 0.001). Tukey HSD post-hoc tests also showed significant differences between Bandtite and Granitec, Bandtite and Ariadent, and Granitec and Ariadent (p < 0.001). All specimens failed at the band-cement interface.

CONCLUSION

The highest and lowest SBS were related to Bandtite and Ariadent cements, respectively. All cements had bond strengths less than the range of bond strengths considered to be clinically acceptable for bonded orthodontic attachments. Mechanical factors are important for band retention.