Assessment of open and incomplete bite correction by incisor overlap and optical density of polyvinyl siloxane bite registration

• Published in: European journal of orthodontics Vol. 28; no. 2; pp. 166 - 172
• Main Authors: Shpack, Nir, Einy, Shmuel, Beni, Lea, Vardimon, Alexander D.
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.04.2006; Oxford Publishing Limited (England)
• Subjects: Child; Dental Materials - chemistry; Dental Models; Dentistry; Female; Follow-Up Studies; Humans; Incisor - pathology; Jaw Relation Record - instrumentation; Jaw Relation Record - methods; Male; Malocclusion, Angle Class II - classification; Malocclusion, Angle Class II - therapy; Open Bite - classification; Open Bite - therapy; Optics and Photonics; Orthodontic Retainers; Polyvinyls - chemistry; Recurrence; Siloxanes - chemistry; Vertical Dimension
• ISSN: 0141-5387; 1460-2210
• DOI: 10.1093/ejo/cji086

Open bite (OB) is a generalized term, which could incorporate subgroups that react differently to vertical correction. The objectives of the present study were to detect vertical treatment changes in incomplete bite (IB: inter-incisor overlap with no lower incisor contact with teeth or palate) and OB (no inter-incisor overlap) groups compared with a complete bite (CB: inter-incisor overlap with full lower incisor contact with teeth or palate) control group, to evaluate treatment response of the central and lateral incisors, and to study the vertico-sagittal interaction. Dental casts were taken at three time points, pre-treatment, post-treatment, and after one year of retention, from 54 Class II patients (22 males and 32 females with a mean age of 11 years 6 months) divided into three groups: CB (n = 21), IB (n = 18) and OB (n = 15). Measurements included incisor overlap (mm) and optical density (OD/mm2) of occlusal bite registration made of polyvinl siloxane. Both CB and IB groups demonstrated post-retention bite opening. However, bite opening in the CB group was three times greater than that in the IB group (e.g. lower lateral = −1.42 mm, 118 OD/mm2 versus −0.40 mm, 107 OD/mm2). Conversely, the OB group showed a significant (P < 0.001) bite closure (e.g. lower lateral = 1.30 mm, −377 OD/mm2). Overjet changes affected OD measurements, causing diversity in OD and millimetric measurements of the lateral incisors in the IB group. In conclusion, the OB group demonstrated a significant stable vertical correction; a post-treatment non-contact inter-incisor relationship was determined by a vertico-sagittal relapse; and full compensation of an IB was not possible.