Contemporary Class II orthodontic and orthopaedic treatment: a review

The biomechanical effects of bimaxillary osteotomies to the patients with mandibular retraction under incisal clenching

The purpose of this study is to investigate the biomechanical effect of bimaxillary osteotomies on patients with mandibular retraction. Mandibular retraction, as a typical maxillofacial deformity, and has great adverse effects on TMJ. Bimaxillary osteotomies are widely used to correct symptoms of mandibular retraction. It is necessary to understand the effect of surgery on temporomandibular disc (TMJ). Five patients with mandibular retraction and 10 asymptomatic subjects were involved in this study. Finite element models of preoperative, postoperative and control group were constructed based on the CT data. Nine sets of concentrated forces were used to simulate the muscle effect and contact method was used to simulate the interaction within the TMJs and dentitions. The results showed that bimaxillary osteotomies could effectively improve the maxillofacial morphology and alleviate the overload in TMJ. The facial asymmetry and right chewing side preference could cause imbalanced stress distributions in the TMJs and interfere the surgical treatment.

Treatment effects and lip profile changes following premolars extraction treatment vs fixed functional treatment in Class II division 1 malocclusion: A randomized controlled clinical trial

OBJECTIVE

The objective of this two-arm parallel randomized controlled trial was to evaluate the treatment effects and lip profile changes in skeletal Class II patients subjected to premolars extraction treatment versus fixed functional treatment.

METHODS

Forty six subjects fulfilling inclusion criteria were randomly distributed into Group PE (mean age 13.03±1.78 years) and Group FF (mean age 12.80±1.67 years) (n=23 each). Group PE was managed by therapeutic extraction of maxillary first premolars and mandibular second premolars, followed by mini-implant-supported space closure; and Group FF, by fixed functional appliance therapy. Skeletal, dental, and soft-tissue changes were analyzed using pre and post-treatment lateral cephalograms. Data obtained from this open label study was subjected to blind statistical analysis.

RESULTS

Extraction treatment resulted in greater increase of nasolabial angle (NLA: 3.1 [95% CI 2.08, 4.19], p<0.001), significant improvement of upper lip (UL-E line: -2.91 [95% CI -3.54, -2.28], p<0.001, UL-S line: -2.50 [95% CI -2.76, -2.24], p<0.001, UL-SnPog': -2.32 [95% CI -2.90, -1.74], p<0.01) and lower lip position (LL-E line: -0.68 [95% CI -1.36, 0.00], p<0.01, LL-S line: -0.55 [95% CI -1.11, 0.02], p<0.01, and LL-SnPog': -0.64 [95% CI -1.20, -0.07], p<0.01), lip thickness (UL thickness: 2.27 [95% CI 1.79, 2.75], p<0.001; LL thickness: 0.41 [95% CI -0.16, 0.97], p<0.01), upper lip strain (UL strain: -2.68 [95% CI -3.32, -2.04], p<0.001) and soft tissue profile (N'-Sn-Pog': 2.68 [95% CI 1.87, 3.50], p<0.01). No significant difference was observed between the groups regarding skeletal changes in the maxilla and mandible, growth pattern, overjet, overbite, interincisal angle and soft tissue chin position (p>0.05). Premolar extraction treatment demonstrated significant intrusion-retraction of maxillary incisors, better maintenance of maxillary incisor inclination, and significant mandibular molar protraction; whereas functional treatment resulted in retrusive and intrusive effect on maxillary molars, marked proclination of mandibular anterior teeth, and significant extrusion of mandibular molars. Both treatment modalities had similar treatment duration. Implant failure was seen in 7.9% of cases, whereas failure of fixed functional appliance was observed in 9.09% of cases.

CONCLUSIONS

Premolar extraction therapy is a better treatment modality, compared to fixed functional appliance therapy for Class II patients with moderate skeletal discrepancy, increased overjet, protruded maxillary incisors and protruded lips, as it produces better dentoalveolar response and permits greater improvement of the soft tissue profile and lip relationship.

Effects of Two-Phase Treatment with Functional Appliances Followed by Extraction versus One-Phase Treatment with Extraction in Class II Growing Patients: A Case-Control Study

Objectives: Fixed appliance treatment with premolar extraction is often required after functional appliance treatment to relieve crowding and improve facial aesthetics in the Asian population. This study compared the treatment efficacy of two approaches for treating Class II division 1 malocclusion: functional appliance followed by fixed appliance treatment with extraction (two-phase) and fixed appliance treatment with extraction (one-phase). Methods: Growing skeletal Class II patients with an overjet of ≥6 mm treated with two- or one-phase orthodontics were included. The two groups consisted of 29 patients (mean age = 12.55) and 30 patients (mean age = 12.72), respectively. Pre- and post-treatment cephalograms were analysed and skeletal, dental, and soft tissue characteristics were compared using independent t-tests. Treatment changes were compared within and between groups using paired and independent t-tests, respectively. Stepwise discriminant analysis was performed to identify the variables that best predicted pre-treatment group allocations. Results: At baseline, there were no significant between-group differences in age, gender, cervical vertebral maturation, or overjet. The two-phase group had greater Class II skeletal discrepancies (ANB angle and Wits appraisal). During treatment, the two-phase group showed greater improvements in intermaxillary relationship and facial convexity compared with the one-phase group (p < 0.01). Following treatment, the two-phase group had a greater L1/APog distance (p < 0.05). Facial convexity and Wits appraisal were identified as parameters significantly influencing the clinicians’ decision to use a one- or two-phase approach. Conclusions: In patients requiring premolar extraction, two-phase (vs. one-phase) treatment produced greater improvements in the intermaxillary relationship and facial convexity.

Long-term (≥15 years) post-treatment changes and outcome quality after Class II:1 treatment in comparison to untreated Class I controls

Aim

To investigate the long-term (≥15 years) post-treatment (Tx) occlusal changes and outcome quality after Class II:1 Tx.

Subjects and Methods

Herbst-MBA Tx had been performed at age 12.8 ± 2.7 years in 119 patients. A recall was conducted and study models from before and after active Tx, after retention as well as after recall were evaluated using standard occlusal variables and the PAR index. These data were compared to 31 untreated Class I controls.

Results

52 out of 119 patients could be located and participated at 33.6 ± 3.1 years. Compared to the 67 patients who did not participate in the recall, the pre- and post-Tx occlusal data of the participants did not differ systematically; however, the PAR scores were higher by 3.0-4.7 points at all times. Pre-Tx, the mean values of the 52 participants were: PAR = 27.2 ± 7.6, Class II molar relationship (MR) = 0.7 cusp widths (cw), overjet = 8.2 mm, overbite = 4.1 mm. After Tx, the PAR score was 3.4 ± 2.2. A Class I MR (0.0 ± 0.1 cw) with normal overjet (2.3 ± 0.7 mm) and overbite (1.3 ± 0.7 mm) existed. At recall, a mild PAR score increase to 8.2 ± 5.5 points had occurred; this was mainly due to increased overjet and overbite values (3.6 ± 1.1 and 2.8 ± 1.6 mm) while the MR was stable (0.0 ± 0.2 cw). For all these variables, similar findings were made in the untreated controls.

Conclusion

The occlusal outcome of Class II:1 Tx showed very good long-term stability. While mild changes occur post-Tx, the long-term result is similar to untreated Class I controls.

Current trends in headgear use for the treatment of Class II malocclusions

Objective: 

To investigate American and Canadian orthodontists’ opinions and perceptions on the use of headgear in the treatment of Class II malocclusions.

Materials and Methods: 

An online survey was sent to randomly chosen orthodontists (n  =  1000).

Results: 

The study was completed by 948 orthodontists; 62% of the orthodontists indicated that they were using headgear in their practice. Those who were not using the appliance (38%) reported that this was mainly due to the availability of better Class II correctors in the market and lack of patient compliance. Of those who use headgear, 24% indicated that the emphasis on headgear use during their residency was an influential aspect of their decision making (P &lt; .05). Nearly a quarter of those who do not use headgear reported that learning about other Class II correctors through continuing education courses was an important factor (P &lt; .05). There was no difference between the headgear users and nonusers in the year and location of practice. Compared with previous studies, this study showed a decline in the use of headgear among orthodontists.

Conclusions: 

Despite a decline, more than half of the orthodontists (62%) believe headgear is a viable treatment. Availability of Class II correctors in the market and familiarity with these appliances though continuing education courses are the reasons for the remaining 38% of orthodontists to abandon use of the headgear.

Comparison of oral-health-related quality of life during treatment with headgear and functional appliances

BACKGROUND

Functional and headgear are two well-known approaches in the treatment of skeletal class II malocclusion in preadolescent children. Assessment of psycho-social impacts of wearing devices during the treatment period is central to enhancing the quality of healthcare services.

AIM

This study aimed to compare oral-health-related quality of life in two groups consisting of children wearing headgear or functional appliances. We also compared these groups with a non-malocclusion group.

DESIGN

The study population consisted of 187, 11- to 14-year-old children in three groups of functional (n = 67), headgear (n = 67) and non-malocclusion (n = 53). Children were asked to complete the translated version of the short form of the Child Perceptions Questionnaire. Total scores and subscale scores of the three clinical groups were compared through ANOVA.

RESULTS

There was no significant difference in mean total scale score and subscale scores between functional and headgear groups (P > 0.05). Significant differences were found in both mean total and subscale scores between the malocclusion and non-malocclusion groups (P < 0.001) except oral symptoms subscale (P > 0.05).

CONCLUSIONS

The results of this study reveal that functional and headgear appliances do not differ in terms of impact on daily life during the treatment. Moreover, both groups have poorer OHQoL compared to malocclusion group.