title: Assessment of open and incomplete bite correction by incisor overlap and optical density of polyvinyl siloxane bite registration.
abstract: 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.
authors.affiliation: Department of Orthodontics, The Maurice and Gabriela Goldschleger, School of Dental Medicine, Tel Aviv Univeristy, Isreal. nshpack@post.tau.ac.il
authors.forename: Nir
authors.initials: N
authors.lastname: Shpack
authors.forename: Shmuel
authors.initials: S
authors.lastname: Einy
authors.forename: Lea
authors.initials: L
authors.lastname: Beni
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Vardimon
mesh_terms: D002648:Child; D003764:Dental Materials / Q000737:chemistry; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007180:Incisor / Q000473:pathology*; D007574:Jaw Relation Record / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008312:Malocclusion, Angle Class II / Q000145:classification / Q000628:therapy; D003765:Models, Dental; D024343:Open Bite / Q000145:classification* / Q000628:therapy; D055095:Optics and Photonics; D018704:Orthodontic Retainers; D011145:Polyvinyls / Q000737:chemistry; D012008:Recurrence; D012833:Siloxanes / Q000737:chemistry; D014716:Vertical Dimension
chemical_list: D003764:Dental Materials; D011145:Polyvinyls; D012833:Siloxanes; C034183:vinyl polysiloxane