Sequencing of bimaxillary surgery in the correction of vertical maxillary excess: retrospective study

Abstract

The aim of this study was to evaluate the precision of bimaxillary surgery performed to correct vertical maxillary excess, when the procedure is sequenced with mandibular surgery first or maxillary surgery first. Thirty-two patients, divided into two groups, were included in this retrospective study. Group 1 comprised patients who received bimaxillary surgery following the classical sequence with repositioning of the maxilla first. Patients in group 2 received bimaxillary surgery, but the mandible was operated on first. The precision of the maxillomandibular repositioning was determined by comparison of the digital prediction and postoperative tracings superimposed on the cranial base. The data were tabulated and analyzed statistically. In this sample, both surgical sequences provided adequate clinical accuracy. The classical sequence, repositioning the maxilla first, resulted in greater accuracy for A-point and the upper incisor edge vertical position. Repositioning the mandible first allowed greater precision in the vertical position of pogonion. In conclusion, although both surgical sequences may be used, repositioning the mandible first will result in greater imprecision in relation to the predictive tracing than repositioning the maxilla first. The classical sequence resulted in greater accuracy in the vertical position of the maxilla, which is key for aesthetics.

Does Mandible-First Sequencing Increase Maxillary Surgical Accuracy in Bimaxillary Procedures?

“…Clockwise (CW) rotation is believed to be more accurate using the maxilla-first approach, while counter clockwise (CCW) rotation should be more accurate using the mandible-first approach 4,5 . However, only 3 studies have compared the 2 sequences in large cohort studies, and none have evaluated how CW or CCW rotation influence the clinical outcome when the mandible or maxilla is sequenced first 1,[10][11][12] .…”

Hypermobile upper lip is highly prevalent among patients seeking treatment for gummy smile

“…The latter could vary significantly from patient to patient because EGD may be caused by several etiologies including altered passive eruption (APE), plaque‐/drug‐induced gingival enlargement, anterior dentoalveolar extrusion, vertical maxillary excess, hypermobile upper lip (HUL), short upper lip, and asymmetric upper lip . The treatment modalities indicated comprise a wide range of less or more invasive procedures, including aesthetic crown lengthening, lip repositioning, orthognathic surgery and orthodontics, and other surgical and nonsurgical options – …”

“…The latter could vary significantly from patient to patient because EGD may be caused by several etiologies including altered passive eruption (APE), plaque-/drug-induced gingival enlargement, anterior dentoalveolar extrusion, vertical maxillary excess, hypermobile upper lip (HUL), short upper lip, and asymmetric upper lip. [13][14][15] The treatment modalities indicated comprise a wide range of less or more invasive procedures, including aesthetic crown lengthening, 16 lip repositioning, [17][18][19] orthognathic surgery and orthodontics, 15,20,21 and other surgical and nonsurgical options. [13][14][15]22 Information on the prevalence of a few of the different EGD etiologies is available only in special populations; examples include gingival enlargement prevalence among patients receiving various medications, [23][24][25][26] APE prevalence in young adults 27 and in patients who had or had not undergone orthodontic therapy, 28 asymmetric upper lip prevalence among dental students, 29 and vertical maxillary excess prevalence in patients with dentofacial deformities.…”

Current trends in orthognathic surgery

“…Complete BSSO does not require a wide mouth opening, which could cause an alteration of the fixed maxillary position. Salmen et al [ 46 ] and Liebregts et al [ 47 ] reported that in the context of planned maxillary impaction and with most surgical movements, the maxilla-first sequence was more accurate.…”