Orthodontic treatment for deep bite and retroclined upper front teeth in children

Evaluation of bond strength of molar orthodontic tubes subjected to reinforcement with flowable and bonding resins

OBJECTIVE

The goal was to evaluate the adhesive shear bond strength (SBS) of orthodontic tubes bonded to molar teeth and reinforced with Transbond XT (3M Science, St. Paul, MN, USA) and flowable resin.

MATERIALS AND METHODS

In all, 120 molar teeth, previously extracted from patients with a mean age of 30 were included. Orthodontic molar tubes were bonded on the vestibular surface of these teeth with one of two types of adhesive (Transbond XT [3M Science, St. Paul, MN, USA] or Orthobond [Morelli, Sorocaba, Brazil]). Each of these groups was subsequently divided into four further groups: control and those subjected to the use of resin reinforcement on the occlusal surface of the bonded tubes with one of three materials (Transbond XT, Tetric N Flow [Ivoclar Vivadent, Ellwangen, Germany], Z 350 Flow [3M Science, St. Paul, MN, USA]). SBS and adhesive remnant index tests were performed to evaluate bond strength and type of fracture of the tubes bonded with the different methods.

RESULTS

The use of resin reinforcement with Transbond XT significantly increased the SBS of tubes bonded with both materials. Flowable composites did not increase the SBS when used as a reinforcement. Less than 50% of the adhesive remained on the vestibular surface after the SBS test in most samples of all groups.

CONCLUSION

Transbond XT orthodontic adhesive and Orthobond adhesive had appropriate bonding strengths for clinical use. Furthermore, the use of a resinous reinforcement with Transbond XT significantly increased the SBS of tubes bonded. However this technique with flowable adhesives (Tetric N Flow and Z350 Flow) did not significantly increase SBS when orthodontic tubes were bonded with Transbond XT or Orthobond.

Orthodontic treatment for deep bite and retroclined upper front teeth in children

BACKGROUND

A Class II division 2 malocclusion is characterised by upper front teeth that are retroclined (tilted toward the roof of the mouth) and an increased overbite (deep overbite), which can cause oral problems and may affect appearance.This problem can be corrected by the use of special dental braces (functional appliances) that move the upper front teeth forward and change the growth of the upper or lower jaws, or both. Most types of functional appliances are removable and this treatment approach does not usually require extraction of any permanent teeth. Additional treatment with fixed braces may be necessary to ensure the best result.An alternative approach is to provide space for the correction of the front teeth by moving the molar teeth backwards. This is done by applying a force to the teeth from the back of the head using a head brace (headgear) and transmitting this force to part of a fixed or removable dental brace that is attached to the back teeth. The treatment may be carried out with or without extraction of permanent teeth.If headgear use is not feasible, the back teeth may be held in place by bands connected to a fixed bar placed across the roof of the mouth or in contact with the front of the roof of the mouth. This treatment usually requires two permanent teeth to be taken out from the middle of the upper arch (one on each side).

OBJECTIVES

To establish whether orthodontic treatment that does not involve extraction of permanent teeth produces a result that is any different from no orthodontic treatment or orthodontic treatment involving extraction of permanent teeth, in children with a Class II division 2 malocclusion.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following electronic databases: Cochrane Oral Health's Trials Register (to 13 November 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2017, Issue 10), MEDLINE Ovid (1946 to 13 November 2017), and Embase Ovid (1980 to 13 November 2017). To identify any unpublished or ongoing trials, the US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform (apps.who.int/trialsearch) were searched. We also contacted international researchers who were likely to be involved in any Class II division 2 clinical trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and controlled clinical trials (CCTs) of orthodontic treatments to correct deep bite and retroclined upper front teeth in children.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results to find eligible studies, and would have extracted data and assessed the risk of bias from any included trials. We had planned to use random-effects meta-analysis; to express effect estimates as mean differences for continuous outcomes and risk ratios for dichotomous outcomes, with 95% confidence intervals; and to investigate any clinical or methodological heterogeneity.

MAIN RESULTS

We did not identify any RCTs or CCTs that assessed the treatment of Class II division 2 malocclusion in children.

AUTHORS' CONCLUSIONS

There is no evidence from clinical trials to recommend or discourage any type of orthodontic treatment to correct Class II division 2 malocclusion in children. This situation seems unlikely to change as trials to evaluate the best management of Class II division 2 malocclusion are challenging to design and conduct due to low prevalence, difficulties with recruitment and ethical issues with randomisation.