EXTRACTION IN ADULT ANTERIOR OPEN BITE PATIENTS : A YES OR NO?

Geoffrey M. Greenlee, Jessica L. Collins, Brian Leroux, Veerasathpurush Allareddy, Cameron Jolley, Kyungsup Shin, Michael Vermette, The National Dental PBRN Collaborative Group, Greg J. Huang

What did the authors aim to do in this study?

This study aimed to determine whether extractions in adult anterior openbite (AOB) patients result in enhanced treatment outcomes and improved short-term stability.

How did the authors evaluate?

As a part of this study, the records of extraction (EXT) and non-extraction (NE) adult patients were identified from all patients treated with fixed appliances through the National Dental Practice-Based Research Network. The selected patients were assigned to the EXT group if at least one incisor, canine, or premolar was extracted, as part of the planned orthodontic treatment. All the patients had mild to severe crowding in at least one dental arch. Crowding was reported by practitioners as mild (1–3 mm), moderate (4–6 mm), or severe (> 6 mm). If crowding scores differed for the maxillary and mandibular arches, patients were categorized by the arch with more significant crowding. Pretreatment (T1) questionnaires were completed by patients and practitioners. Information regarding the amount of pretreatment crowding, the method of treatment provided, and patient characteristics were included in the doctor’s questionnaire. Cephalograms and intraoral photographs were also obtained at this timepoint. At the completion of treatment (T2), cephalograms and intraoral photographs were collected. Skeletal and dental cephalometric landmarks and measurements were identified and measured as part of a previous study.

Fig 1. Cephalometric landmarks

The treatment was dependant on the T1, T2, and T3 openbite severity, which was assessed using the Photographic Openbite Severity Index (POSI). This system was developed to categorize the severity of the AOB pretreatment and posttreatment and was tested for validity and reliability. For this study, treatment success was defined as a POSI score of 0 or 1, indicating a successful treatment included vertical overlap at both central incisors. Pretreatment patient demographics were collected for the EXT and NE groups. Treatment success was defined as a POSI score of 0 or 1 and was also evaluated with cephalometric overbite. Both methods assessed positive vertical overlap at the central incisors. Means for all cephalometric outcomes were calculated at T1 and T2.

Fig 2. Photographic Openbite Severity Index

A multivariable linear regression analysis was performed for each outcome variable to adjust for the influence of age, gender, previous treatment, previous extraction, and moderate to severe crowding. This model was used to assess the impact of extractions on cephalometric treatment outcomes after adjustment for explanatory variables. Stability was evaluated for patients that achieved success posttreatment. T2 and T3 POSI scores were compared with the Fischer’s exact test.

What did the authors find?

In the study, the pretreatment and posttreatment records were collected for 115 patients. Thirty-three were treated with extractions; 82 were treated without extractions. The EXT group was younger, more crowded, and had less previous orthodontic treatment. Success rate of AOB correction in the EXT group was slightly higher (97%) than the NE group (92%) but not statistically different. No significant differences were observed in skeletal outcomes. The EXT group exhibited more lingual tipping and posterior movement of maxillary and mandibular incisors and less extrusion of mandibular incisors. Dental changes in the EXT group were associated with increased nasolabial angle and lip retraction.

What did the authors conclude?

• No difference was found for success in closing AOB between adult patients treated with or without extractions, possibly because the success levels were high in both groups.

• EXT patients have clinically significant retraction and lingual tipping of incisors with associated retraction of soft tissues at the completion of treatment.

• Over 90% of patients maintained closure of their AOB at follow-up.

What do we think about it?

Anterior openbite (AOB) is a dental condition in which patients are unable to obtain a vertical overlap of the incisors while occluding on the posterior teeth. This common condition can be caused by dental discrepancies, skeletal discrepancies, oral habits such as thumb-sucking or tongue habits, airway obstruction, and condylar dysplasia etc. Such patients may face challenges due to malocclusion, which would include difficulty during eating and speech, and in severe cases, their aesthetics can be compromised. Orthodontists employ many approaches to achieve AOB closure, including elastic traction, habit appliances, and temporary anchorage device (TAD)-supported intrusion. Most often, practitioners are successful in achieving positive overbite regardless of treatment modality. Extractions are considered helpful in the orthodontic correction of AOB. Removal of teeth is believed to have two potential benefits, the wedge effect bringing the point of posterior dental contact further away from the mandible’s axis of closure and the drawbridge effect retracting and rotating incisors occlusally to increase the vertical overlap. This study was a very extensively carried out procedure where all the above mentioned factors were considered & even the stability was assessed even if it was for a short term duration. It has various drawbacks such as the study was carried out on a smaller sample size & also the long term stability of the patients was not evaluated. Inspite of this, the analysis was still was able to encapsulate the significance of managing the AOB cases in the different methods available & inferred that almost with or without extraction, the treatment outcome & stability was similar. This will help us as clinicians to opt the options which are more conservative & less invasive for the patients.

Greenlee GM, Collins JL, Leroux B, Allareddy V, Jolley C, Shin K, Vermette M; National Dental PBRN Collaborative Group; Huang GJ. Treatment outcomes and short-term stability in adult anterior openbite patients treated with or without extractions: a National Dental Practice-Based Research Network study. Angle Orthod. 2025 Jan 30.