Dentoskeletal effects of class II malocclusion treatment with the modified Twin Block appliance

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Abstract

Background

The purpose of this study was to prospectively assess the dentoskeletal effect of a modified Twin Block appliance for treatment of class II malocclusions.

Material and Methods

Lateral cephalograms of 25 Class II malocclusion patients were compared to evaluate skeletal, dentoalveolar and soft tissue changes pre- and post-treatment with a modified Twin Block appliance. A total of 33 angular and linear variables were used for analysis. The differences were calculated at the start and end of treatment. The paired T test was performed to compare the cephalometric measurements before and after treatment.

Results

Compared the pre- and post- treatment measurements, there was a significant increase in SNB ( P<0.001), CO-Gn ( P<0.001), ANS-Me ( P=0.001), Mandibular base ( P<0.001), Lower 1 to NB (°) ( P=0.004), Lower 1 to NB (mm) ( P<0.001), and Z-angle ( P=0.001) following functional therapy with modified Twin Block appliance. On the other hand, a significant decrease was observed in ANB ( P<0.001), NA-Pog ( P<0.001), overjet ( P<0.001), and overbite ( P=0.007), Upper 1 to palatal plane ( P=0.007), UL-E-line ( P<0.001), LL-E-line ( P=0.001), and H-angle ( P=0.002) after treatment with modified Twin Block appliance.

Conclusions

The modified Twin-Block improves facial esthetics in Class II malocclusion by a combination of changes in skeletal as well as dentoalveolar structures. The increase of mandibular unit length was observed to be due to a true mandibular growth not just a repositioning of the mandible. The modified appliance, however, did not show any superior effects in terms of less dental compensation compared to the conventional Twin–Block appliance.

Key words:Dentoskeletal effect, Modified Twin Block, Class II malocclusion.

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Most cited references 21

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A soft-tissue cephalometric analysis and its use in orthodontic treatment planning. Part I.

Heather Holdaway (1983)

This article presents a soft-tissue analysis which demonstrates the inadequacy of using a hard-tissue analysis alone for treatment planning. The material and methods used to develop this technique came from years of observation and description of patients from the private practice of the author. The findings indicate that, in general, for adolescents the normal or usual thickness of the soft tissue at point A is 14 to 16 mm. As point A is altered by tooth movement, headgear, etc., the soft tissue will follow this point and remain the same thickness. When there is taper in the maxillary lip immediately anterior to the incisor, as in protrusive dentures, the tissue will thicken as the incisors are moved lingually until the tissue approaches the thickness at point A (within 1 mm. of the thickness at point A). When the lip taper has been eliminated, further lingual movement of the incisor will now cause the lip to follow the incisors in a one-to-one ratio. These concepts are predictable in adolescents when the lip thickness at point A is within the normal range. Some exceptions are as follows: Even if there is lip taper, if the tissue thickness at point A is very thin (for example, 9 to 10 mm.), the lip may follow the incisor immediately and still retain the taper. If the tissue at point A is very thick (for example, 18 to 20 mm.), the lip may not follow incisor movement at all. Adult tissue reaction is similar to the first exception. Even though there may be lip taper, the lips will usually follow the teeth immediately. Cases are presented to demonstrate these concepts and to illustrate a normal or acceptable range of variation for facial harmony related to variations in skeletal convexity.

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Class II functional orthopaedic treatment: a systematic review of systematic reviews.

V D'Antò, Jay R Bucci, L L Franchi … (2015)

This Systematic Review (SR) aims to assess the quality of SRs and Meta-Analyses (MAs) on functional orthopaedic treatment of Class II malocclusion and to summarise and rate the reported effects. Electronic and manual searches were conducted until June 2014. SRs and MAs focusing on the effects of functional orthopaedic treatment of Class II malocclusion in growing patients were included. The methodological quality of the included papers was assessed using the AMSTAR (Assessment of Multiple Systematic Reviews). The design of the primary studies included in each SR was assessed with Level of Research Design scoring. The evidence of the main outcomes was summarised and rated according to a scale of statements. 14 SRs fulfilled the inclusion criteria. The appliances evaluated were as follows: Activator (2 studies), Twin Block (4 studies), headgear (3 studies), Herbst (2 studies), Jasper Jumper (1 study), Bionator (1 study) and Fränkel-2 (1 study). Four studies reviewed several functional appliances, as a group. The mean AMSTAR score was 6 (ranged 2-10). Six SRs included only controlled clinical trials (CCTs), three SRs included only randomised controlled trials (RCTs), four SRs included both CCTs and RCTs and one SR included also expert opinions. There was some evidence of reduction of the overjet, with different appliances except from headgear; there was some evidence of small maxillary growth restrain with Twin Block and headgear; there was some evidence of elongation of mandibular length, but the clinical relevance of this results is still questionable; there was insufficient evidence to determine an effect on soft tissues.

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A prospective evaluation of Bass, Bionator and Twin Block appliances. Part I--The hard tissues.

J. D. Morris, H P Illing, Gilbert Lee (1998)

A prospective clinical study with a random allocation of 47 adolescent patients to three different functional appliance groups was established and compared with an untreated control group over a 9-month period. Treatment was undertaken with either a Bionator, Twin Block, or Bass appliance. Pre- and post-treatment cephalograms were used to quantify the skeletal and dentoalveolar changes produced by the appliances and compared with those observed in the control group as a result of growth. Both the Bionator and Twin Block appliances demonstrated a statistically significant increase in mandibular length (3.9 +/- 2.7 mm; 3.7 +/- 2.1 mm, respectively) compared with the control group (P < 0.05), with an anterior movement of pogonion and point B. Highly statistically significant increases (P < 0.01) were seen in lower face heights for all the appliance groups compared with the control group. The Twin Block group showed the least forward movement of point A due to a change in the inclination of the maxillary plane. The Bionator and Twin Block groups showed statistically significant reductions in the inclination of the upper incisors to the maxillary plane (P < 0.05). The Bass group showed minimal change in the inclination of the lower labial segment to the mandibular plane. The Bionator group demonstrated the greatest proclination of the lower labial segment (4.0 +/- 3.6 degrees). Clinically important changes were measured in all the appliance groups when compared with the control group. Differences were also identified between the functional appliance groups. The Twin Block appliance and, to a lesser extent, the Bionator appeared the most effective in producing sagittal and vertical changes.

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Author and article information

Journal

Journal ID (nlm-ta): J Clin Exp Dent

Journal ID (iso-abbrev): J Clin Exp Dent

Journal ID (publisher-id): Medicina Oral S.L.

Title: Journal of Clinical and Experimental Dentistry

Publisher: Medicina Oral S.L.

ISSN (Electronic): 1989-5488

Publication date (Electronic): 1 December 2019

Publication date Collection: December 2019

Volume: 11

Issue: 12

Pages: e1093-e1098

Affiliations

[1 ]Orthodontics Research Center, Department of Orthodontics, Shiraz University of Medical Science, Shiraz, Iran

Author notes

Orthodontic Research center School of Dentistry Qom Abad Blv, Ghasrodasht AV, Shiraz, Iran , E-mail: nedababanouri@ 123456yahoo.com

Conflict of interest statement:The authors declare that there is no conflict of interest.

Article

Publisher ID: 56241

DOI: 10.4317/jced.56241

PMC ID: 6894910

PubMed ID: 31824588

SO-VID: b504da4f-ecb7-4b49-a941-c58486cc55e9

License:

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Dentoskeletal effects of class II malocclusion treatment with the modified Twin Block appliance

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Abstract

Background

Material and Methods

Results

Conclusions

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Pluto Journals

Most cited references 21

A soft-tissue cephalometric analysis and its use in orthodontic treatment planning. Part I.

Class II functional orthopaedic treatment: a systematic review of systematic reviews.

A prospective evaluation of Bass, Bionator and Twin Block appliances. Part I--The hard tissues.

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