Timing of early correction of mandibular hypoplasia in skeletal class II malocclusion: a review

Skeletal Class II malocclusion is a common malocclusion seen in clinics. It is characterized by maxillary protrusion and mandibular retrognathia and has a high incidence in adolescent mixed dentition and early permanent dentition. The early functional correction has achieved some clinical results in treating skeletal Class II malocclusion with mandibular hypoplasia. During treatment, the timing of correction is the key factor in determining the therapeutic effect, although it is difficult to understand. This review focuses on the timing of early correction of mandibular hypoplasia in combination with relevant assessment indicators and historical literature from four perspectives-the law of mandibular growth and development, the necessity of early treatment, the timing of early treatment, and the determination of the peak period of mandibular growth and development-to provide a theoretical reference for the timing of the treatment of clinical skeletal Class II malocclusion. This review shows that skeletal Class II mandibular growth has different characteristics in males and females. Bone growth assessment before treatment helps diagnose mandibular developmental morphology and the timing of early correction in adolescents with skeletal Class II malocclusion and hypoplasia of the mandible.

Comparative treatment outcomes after bilateral extractions of maxillary second molars or first premolars in patients with class II malocclusion: a retrospective study

BACKGROUND

This retrospective cohort study aimed to compare treatment results between bilateral extraction of upper second molars (M2) and first premolars (P1) in terms of treatment timing, cephalometry, upper third molar alignment and relapse in the long-term.

METHODS

Fifty-three consecutively treated Caucasian patients with a brachyfacial pattern, skeletal class I and dental class II requiring extraction in the maxilla due to crowding were retrospectively divided into group I (M2 extracted; N = 31) and II (P1 extracted; N = 22). Fixed appliances were inserted after extraction and after distalisation of the first molars in group I. Post-treatment lateral cephalograms were digitally analysed and compared between groups. Six to seven years later relapse and success of upper third molar alignment were clinically evaluated as well as orthodontic treatment duration, pre-treatment age and gender recorded.

RESULTS

After debonding patients with second molar extraction showed significantly smaller values for the Wits-appraisal, but higher values for index and facial axis. Extracting first premolars caused significantly more retroinclination/-position of anterior teeth and an increased profile concavity, more relapse and less successful alignment of upper third molars. Orthodontic treatment duration, pre-treatment age and gender were not significantly different between groups.

CONCLUSIONS

Bilateral extraction of upper first premolars or second molars may solve dental crowding in skeletal class I dental class II patients with a brachyfacial growth pattern. Upper second molar extraction seems to affect maxillary third molar alignment, long-term stability and dental and soft-tissue cephalometric parameters positively, but no intervention proved to be clearly superior.

Third Molar Angulation Changes in Class II Div I Malocclusion Subjects Treated with Extraction of Four Premolars: A Retrospective Study

Aim:

The aim of this study was to assess the changes in maxillary and mandibular third molar inclinations in individuals with class II div 1 malocclusion, before and after orthodontic treatment with extraction of all four first premolars.

Materials and Methods:

This retrospective study consisted of the pretreatment and posttreatment records of 30 patients that were obtained from the archives of the department of orthodontics and dentofacial orthopedics in A B Shetty Memorial Institute of Dental Sciences. The maxillary third molar’s relation to the palatal plane and the mandibular third molar’s relation to the mandibular plane were measured. The paired t test was used to calculate pre- and posttreatment changes. A value of P < 0.05 was considered to be statistically significant.

Results:

The maxillary third molars showed a mean correction of 6.15° (P < 0.001) and the mandibular third molars showed a mean correction of 5.10° (P < 0.001).

Conclusion:

Maxillary third molars showed more uprighting when compared to the mandibular third molars and that both maxillary and mandibular third molars showed an improvement in their angulations to their respective planes after extraction of the first premolars. However, the results of the study cannot be analyzed to state if the third molars do become fully functional.

Effect of class II extractions and functional appliance treatment on smile esthetics

BACKGROUND

Class II malocclusion is routinely observed in orthodontics. Its treatment usually revolves around the growth modification or the extractions of the teeth. Identifying treatment that leads to the greatest improvement can aid clinicians in providing the desired smile esthetics.

OBJECTIVES

The aim of the study was to compare smile esthetics between treatment groups by measuring various smile variables and the esthetic perceptions of 3 panels of raters.

MATERIAL AND METHODS

A cross-sectional study was performed on 66 patients equally divided into the functional appliance (FA) and upper first premolar extraction (UPE) groups. Eight smile variables were measured on post-treatment photographs using the Adobe Photoshop® software. Ten orthodontic residents, general dentists and laypersons performed the subjective evaluations of smiles using the visual analog scale (VAS). The Mann-Whitney U-test was applied to compare smile variables between the groups. The Kruskal-Wallis test was used to compare esthetic scores (ES) among the raters. The simple linear regression analysis, followed by the multiple linear regression analysis was applied to determine the smile variables associated with the ES values.

RESULTS

Statistically significant differences were found between the FA and UPE groups for the buccal corridor ratio (BCR) (p = 0.046), the visible dentition width ratio (VDWR) (p = 0.019) and the arch form index (AFI) (p < 0.001). The Kruskal-Wallis test showed significant differences in ES among the raters for the FA (p < 0.001) and UPE (p = 0.004) groups. The simple linear regression analysis showed significant associations between ES and the patient's age (p = 0.002), BCR (p = 0.020) and VDWR (p = 0.006). The multiple linear regression analysis showed that age (p = 0.008) and VDWR (p = 0.021) were significantly associated with the ES values.

CONCLUSIONS

The FA group had narrower buccal corridor spaces, a greater visible dentition width and a wider arch form in their smiles. The UPE group showed an increase in the buccal corridor width. Each panel rated the FA appliance group as superior.

Pharyngeal dimensional changes in class II malocclusion treatment when using Forsus® or intermaxillary elastics - An exploratory study

OBJECTIVE

Pharyngeal airway obstruction can facilitate some forms of sleep disorder breathing (SDB) in susceptible children, especially in those having class II malocclusion. Changes in the anatomic areas surrounding the pharyngeal region during orthodontic treatment could hypothetically impact the pharyngeal airway dimensions. Management of a class II malocclusion on a growing individual with either intermaxillary elastics or different removable or fixed class II appliance designs have been proposed over the last century. The objective of this retrospective exploratory cohort study is to investigate to what extent the class II malocclusion treatment with either intermaxillary elastics (IME) or Forsus® fatigue resistance device (FFRD) leads to changes in oropharyngeal airway dimensions.

MATERIALS AND METHODS

Twenty-nine patients diagnosed as class II with an average age of 12.7years were included in this study, (11 males, 18 females). The sample was divided into group 1: IME and group 2: FFRD. CBCT's scans before (T1) and after treatment (T2) were obtained and analysed using Dolphin software. Reliability was obtained using Intraclass Correlation Coefficient (ICC). Descriptive statistics, ANOVA and paired t-test were used for analysis.

RESULTS

Intra-rater reliability test was excellent in all measurements for both groups. There were no statistically significant differences in pharyngeal airway dimensions between both groups (P=0.919). A statistically significant correlation was found for sex, where male patients had the highest increase in oro-space area (ORS), and in oropharyngeal volume. Children under 14-year-old in IME group showed statistically negative correlation for sub-mandibular (SM) and for ORS, meaning the younger the greatest increase. Additionally, individuals younger than 14years had a statistically significant increase in the vertical dimension.

CONCLUSIONS

Both orthodontic treatment approaches appear to be associated with a similar increase in oropharyngeal airway dimensions. Male patients under 14-year-old had a greater significant increase compared to female patients and older children. Normal pharyngeal dimensions changes were not accounted for.

A Review on Comparison of Tooth Size Discrepancies among Angle's Class I, II, and III Malocclusion: Is There a Significance?

AIM

The contemporary article aims to review and compare various literatures concerning different conclusions regarding the correlation between tooth size discrepancy (TSD) and Angle's malocclusion groups.

BACKGROUND

Acquiring the ideal occlusion plays one of the major roles while designing the treatment plan for an orthodontic patient, any alterations in the individual tooth sizes are called TSD and will hinder this prime requirement. By determining the correct tooth size ratio, it further helps in acquiring the accurate interdigitation, balanced occlusion, and also predicting the orthodontic treatment results. Various investigations were carried out to know the correlation between tooth size discrepancies and different malocclusion groups, of which, a few reported a statistically significant difference whereas others reported no significant difference.

REVIEW RESULTS

A computerized database quest was operated utilizing the Medline database (Pubmed/Medline) for original research and review articles. Publications between 1946 and 2018 were included. Four hundred twenty-one articles were recovered from database search and, among them, 66 articles were selected to review the full-article.

CONCLUSION

Although a comparison was done between the tooth-size ratios and malocclusion groups (classes I, II, and III), many investigators noted no significant difference but there is an inadequacy in the data particularly related to subgroups of Angle's classification of malocclusion among these investigations; therefore, further studies are required to interpret this correlation.

CLINICAL SIGNIFICANCE

As there is high incidence of tooth size discrepancies noted in the previous literature orthodontist, Bolton's analysis regardless of malocclusion group, sex, and ethnicity is highly recommended.

Effect of removable functional appliances on mandibular length in patients with class II with retrognathism: systematic review and meta-analysis

BACKGROUND

Orthopedic functional devices, are used to improve mandibular length in skeletal class II patients. However, the orthopedic functional device with the best effect to increasing the mandibular length, has not been identified before. Thus, the aim of the present investigation was to evaluate Randomized Controlled Trials (RCT), to determine the best functional appliance improving mandibular length in subjects with retrognathism.

METHODS

A systematic review and meta-analysis was performed, including studies published and indexed in databases between 1966 and 2016. RCTs evaluating functional appliances' effects on mandibular length (Condilion-Gnation (Co-Gn) and Condilion-Pogonion (Co-Po)), were included. Reports' structure was evaluated according to 2010 CONSORT guide. The outcome measure was distance between Co-Gn and/or Co-Po after treatment. Data were analyzed with Cochran Q Test and random effects model.

RESULTS

Five studies were included in the meta-analysis. The overall difference in mandibular length was 1.53 mm (Confidence Interval (CI) 95% 1.15-1.92) in comparison to non-treated group. The Sander Bite Jumping reported the greatest increase in mandibular length (3.40 mm; CI 95% 1.69-5.11), followed by Twin Block, Bionator, Harvold Activator and Frankel devices.

CONCLUSIONS

All removable functional appliances, aiming to increase mandibular length, are useful. Sander Bite Jumping was observed to be the most effective device to improve the mandibular length.

Semi-longitudinal Study of the Mcnamara Cephalometric Triangle in Class II and Class III Subjects Grouped by Cervical Vertebrae Maturation Stage

The aim was to compare the McNamara cephalometric triangle values in untreated normodivergent Class II and Class III malocclusion subjects of Latin American origin grouped by cervical vertebrae maturation stage to an untreated Class I malocclusion normodivergent control group. The study was conducted on a sample of 610 pretreatment lateral cephalograms (250 male, 360 female), examined and grouped according to their anteroposterior skeletal relationship (Class I, II or III), cervical vertebrae maturation stage (Pre Pubertal Peak P1 = CS1 and CS2, Pubertal Peak P2= CS3 and CS4, and Post Pubertal Peak P3 = CS5 and CS6) and sex. Co-A, Co-Gn and ENA-Me were measured in each lateral cephalogram. ANOVA and Tukey HSD post-hoc tests were performed to determine differences between the groups. The results showed that in males, the greatest maxillary and mandibular dimensional increases occurred during the P3 stage (CS5 to CS6), while in females, they occurred in the P2 stage (CS3 to CS4). The Co-A and Co-Gn showed significant differences between the malocclusion classes (p<0.05). The maxillary lengths in Class II subjects and the mandibular lengths in Class III subjects were already higher at the beginning of the period evaluated (P1). A worsening trend for the Class II and III malocclusions was identified during the period evaluated. Finally, changes in the McNamara cephalometric triangle values were markedly different in the three normodivergent skeletal malocclusion classes. In these Latin American subjects the pubertal growth spurt occurred at different times with respect to the Caucasian and Asian norms.

[Surgical treatment of Obstructive Sleep Apnea Syndrome. Functional assessment]

INTRODUCTION

Obstructive Sleep Apnea Syndrome (OSAS), when associated with adverse skeletal dysmorphia, can be managed by curative surgery i.e. advanced maxillomandibular associated with genioplasty and uvulopalatoglossoplasty ("6 in 1"). The purpose of this study was to assess the functional impact of this procedure.

MATERIALS AND METHODS

This retrospective study was made on 27 patients with OSAS surgically treated between 1998 and 2009. The functional results were considered satisfactory when postoperative apnea/hypopnea index (AHI) was <15/h and/or at least decreased by 50%.

RESULTS

After surgical treatment, the AHI dropped below 15/h for 70.4%, and for 92.6% it was at least decreased by 50%, one year after surgery. A significant concomitant decrease of the body mass index (BMI) was also observed.

DISCUSSION

This "6 in 1" surgical management seemed to effectively treat OSAS in the selected cases.