title: Importance of occlusal plane reproduction on the semi-adjustable articulator in planning maxillary impactions for orthognathic surgery.
abstract: BACKGROUND
  The aim of this study was to evaluate whether a 6° counterclockwise change in occlusal plane inclination would produce significant modifications on the final result of a maxillary impaction and mandible advancement model surgery.
  
  
  METHODS
  Four groups were used in this study, with ten identical maxillary casts and one mandibular cast mounted on the same semi-adjustable articulator, with the same malocclusion. The occlusal plane of the two control and study groups had an inclination of 13° and 7°, respectively. Preoperative and postoperative measures were performed using the Erickson platform and impactions of 6 and 10 mm were tested. To control these movements during model surgery, two splints were fabricated using another two maxillary and mandibular casts mounted with occlusal plane of 13°, simulating the proposed movement.
  
  
  RESULTS
  The results were compared using the t test. Only the antero-posterior movement of the upper incisor was statistically significant for both study groups (p < 0.05), with a mean of 0.48 and 0.94 mm in the 10 and 6 mm impaction groups, respectively.
  
  
  CONCLUSIONS
  This information means that if an error in the occlusal plane transference occur, it will not be clinically significant, because differences smaller than 1 mm does not have influence on soft and hard tissue final result.
authors.affiliation: Oral and Maxillofacial Surgery Division, Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas-UNICAMP, Av. Limeira 901, Piracicaba, SP, Brazil. marchiori_erica@hotmail.com
authors.forename: Erica Cristina
authors.initials: EC
authors.lastname: Marchiori
authors.forename: Robson Rodrigues
authors.initials: RR
authors.lastname: Garcia
authors.forename: Roger William Fernandes
authors.initials: RW
authors.lastname: Moreira
mesh_terms: D002508:Cephalometry; D003725:Dental Articulators; D003735:Dental Casting Technique; D003766:Dental Occlusion; D003767:Dental Occlusion, Balanced; D006801:Humans; D008312:Malocclusion, Angle Class II / Q000601:surgery; D019186:Mandibular Advancement / Q000379:methods*; D008437:Maxilla / Q000601:surgery*; D003765:Models, Dental; D010347:Patient Care Planning