Greg Huang DMD, MSD, MPH
The crown- or banded-type Herbst appliance has more immediate dental than skeletal effects on Class II division 1 malocclusions.
This conclusion is based on two articles reporting on the same population of subjects.
In growing individuals with Class II malocclusion, what are the maxillary and mandibular skeletal and dental treatment effects produced by crown or banded Herbst, compared to a Class II untreated control group?
An all-language search of several electronic databases spanning the time from 1966 to March 12 2007 was conducted. Inclusion criteria were: a) clinical trials, b) use of crown/banded Herbst, c) skeletal/dental changes evaluated with cephalograms, d) nonsyndromic or medically compromised patients, e) no surgical intervention, f) non-treated Class II control group, g) cases were randomized or consecutively started/treated, h) measurements taken soon after Herbst removal, i) no other orthodontic treatment during evaluation period. Hand searching of reference lists was performed, and efforts were made to contact authors for additional information. The outcomes were various dental and skeletal relationships, measured in the antero-posterior dimension.
55 articles were retrieved for full evaluation, 3 articles met the inclusion criteria. Of these, two article came from the same sample but reported different measurements. There were a total of 52 active treated cases and 50 untreated controls. The studies found minimal skeletal effects on the maxilla and variable effects on the mandible due to possible measurement inaccuracies. The studies showed a retroclination of maxillary incisors; a proclination of mandibular incisors; a reduction of overjet, overbite and ANB angle; a distalization of maxillary first molars and a mesialization of mandibular first molars; and an increase in mandibular plane angle. The methodological quality of the studies was judged to be poor.
No identified studies reported long-term results. The three articles only evaluated immediate changes. It is difficult to judge the results seen as conclusive, as dental relapse and/or mandibular growth rate deceleration could have occurred after the endpoint of the trials. Controversy was identified for the mandibular skeletal effects, as variable results were reported based upon the measurements used.
Source of Funding:
Importance and Context:
It is important to understand if the magnitude and mechanism of correction produced by the fixed type Herbst is similar to other types of functional appliances, as many other types of functional appliances are removable, and thus dependent upon patient compliance.
Strengths and Weaknesses of the Systematic Review:
The review was thorough. The authors searched 7 databases, hand searched reference lists, and attempted to contact authors when necessary. The inclusion criteria were stated, and lists of the included and excluded studies were provided with supporting reasons. Two independent reviewers assessed the articles for inclusion, performed data abstraction, and judged the quality of the included articles.
Strengths and Weaknesses of the Evidence:
Only 3 articles were found to satisfy the inclusion criteria, and 2 of the articles that came from the same study reported different measurements. Also, the authors noted that making direct comparisons between the articles was difficult due to different landmarks, differing age group ranges, and different treatment durations, all of which prohibited a meta-analysis. The 3 studies were of poor methodological quality. The included studies were not randomized trials, and 1 of them used a historical control. The evidence in this review reports only on immediate effects and are not conclusive for long-term results.
Implications for Dental Practice:
The current evidence only reports on immediate dento-alveolar changes with fixed Herbst appliances. It appears that the fixed and removable Herbst have similar short-term dental and skeletal effects, and these also appear to be similar to the response produced by other types of functional appliances.
 Flores-Mir, C., et al., Skeletal and dental changes in Class II division 1 malocclusions treated with splint-type Herbst appliances. A systematic review. Angle Orthod, 2007. 77(2): p. 376-81.
 Harrison, J.E., K.D. O'Brien, and H.V. Worthington, Orthodontic treatment for prominent upper front teeth in children. Cochrane Database Syst Rev, 2007(3): p. CD003452.