Posterior transpalatal distraction with pterygoid disjunction: A short-term model study

doi:10.1067/mod.2001.118401

American Journal of Orthodontics and Dentofacial Orthopedics

Volume 120, Issue 5, November 2001, Pages 498-502

https://doi.org/10.1067/mod.2001.118401 Get rights and content

Abstract

The transpalatal distractor (TPD) allows for maxillary expansion according to the concepts of distraction osteogenesis. Unlike tooth-borne, surgically assisted rapid palatal expansion devices, the bone-borne TPD is designed to avoid periodontal ligament compression, buccal root resorption, fenestration, tooth tipping, and orthodontic relapse during and after the expansion. When the distractor is placed on the palate at the level of the second premolar and pterygomaxillary disjunction is not performed, more expansion occurs in the anterior part of the maxilla than it does in the posterior. The aim of this investigation was to test the hypothesis that pterygomaxillary disjunction and placement of the TPD on the palate at the level of the first molars result in more parallel expansion of the maxillary segments. Twenty consecutive patients were included in a prospective way, and their predistraction and postdistraction models were electronically analyzed. The change in resistance and force application resulted, on average, in parallel segment expansion. The results showed that pterygomaxillary disjunction and posterior placement of the TPD are indicated for patients having transverse maxillary deficiency with lateroposterior crossbite. (Am J Orthod Dentofacial Orthop 2001;120:498-502)

Section snippets

Material and methods

The study group comprised 20 patients (12 females and 8 males), average age 20 years (range, 12-42 yrs). All patients were in the permanent dentition, and none had congenital craniofacial anomalies. No orthodontic appliances were used during the study, and bilateral expansion was achieved with the TPD. Informed consent was obtained for all patients. Osteotomies were performed under general anesthesia. A round #33 bur was used to transect the lateral support (zygomatic buttress), and a short,

Results

Expansion averaged 29.9% (SD 14.1%) at the level of the canines, 28.3% (SD 11.6) at the level of the first premolars, and 20.8% (SD 7.2) at the level of the first molars. The expansion percentages must be related to the original widths at the different levels to learn the differential movement of the anterior and posterior parts of the segments. The average original intercanine and interpremolar distances were 75% and 77.7%, respectively, of the average original intermolar distance. The

Discussion

The midpalatal suture, the zygomatic buttress, the piriform aperture, and the pterygomaxillary junction are the primary sites of resistance to maxillary expansion.17, 18, 19, 20 With increasing interdigitation in the palatal suture and maturation of the facial skeleton, the need to release the resistance in the suture and to section the lateral and posterior buttresses becomes obvious.21, 22 The palatal mucoperiosteum constitutes a secondary site of resistance when immediate expansion is

Conclusions

Transpalatal distraction results in parallel expansion of the maxillary segments in the axial plane when the TPD device is placed at the level of the first molars and pterygomaxillary disjunction is performed.

Acknowledgements

We gratefully acknowledge the assistance of Professor Luc Dermaut of the University of Ghent for his suggestions on Figure 3.

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Cited by (80)

Age-related changes in the midpalatal suture: Comparison between CBCT staging and bone micromorphology
2024, Bone
The age-related maturation of the human midpalatal suture is challenging to predict, but critical for successful non-surgical rapid maxillary expansion (RME). While cone-beam computed tomography (CBCT) can be used to categorize the suture into stages, it remains unclear how well the stages predict the actual micromorphology of the palate. To address this clinically relevant question, we used CBCT together with three-dimensional micro-computed tomography (μCT) analysis on 24 human palate specimens from individuals aged 14–34 years. We first classified the specimens into stages (A-E) using CBCT images and then correlated the results with our comprehensive μCT analysis. Our analysis focused on several factors, including bone volume fraction (BV/TV), sutural width, volume, interdigitation, ossification, and their associations with age, CBCT stage, and sex. Our μCT analysis revealed a decrease in sutural width and volume after the age of 20 years, accompanied by sutural closure beginning in the palatal segment. The overall rate of ossification remained low but increased after the age of 20 years. No significant differences were found between males and females. Importantly, we also found no correlation between individual age and CBCT stages. Furthermore, there was no association between CBCT stages and patalal suture volume, ossification and interdigitation.
Taken together, our findings cast doubt on the reliability of CBCT stage as a means of predicting skeletal maturity of the palatal suture, as it appears to lack the precision required to accurately assess the true micromorphology of the palatal suture. Future investigations should explore whether alternative CBCT parameters may be more useful in addressing the challenging question of whether RME requires surgical bone weakening.
Computational fluid dynamics and NOSE scale to assess nasal respiratory function, and correlation with linear maxillary measurements after surgically assisted rapid maxillary expansion
2023, International Journal of Oral and Maxillofacial Surgery
Nasal obstruction is common in patients with a transverse maxillary deficiency. The aim of this study was to determine the variation in nasal airway resistance in adult patients with a transverse maxillary deficiency before and after surgically assisted rapid maxillary expansion (SARME) by computational fluid dynamics (CFD) using computed tomography scans, and to correlate this variation with maxillary linear measurements obtained by means of plaster models. The subjective symptoms of nasal obstruction were also analysed using a visual analogue scale (VAS) for nasal breathing and the Nasal Obstruction Symptom Evaluation (NOSE) scale. There was a median reduction of 21% in nasal airway resistance post SARME (P = 0.002). The NOSE scale score decreased (P < 0.001) and nasal breathing quality VAS scores increased in both nostrils (P < 0.001). Transverse measurements between the upper canines (C–C), premolars (PM–PM), and molars (M–M), and maxillary perimeter showed significant increases (P < 0.001), while the anteroposterior maxillary arch length showed a significant decrease (P = 0.016). An inverse proportional correlation was found between PM–PM and nasal airway resistance (r = −0.395; P = 0.034) and between M–M and nasal airway resistance (r = −0.383; P = 0.040). These results demonstrate that surgically expanding the posterior region of the maxilla results in decreased nasal airway resistance, decreased obstructive symptoms, and improved patient respiratory quality.
Do Gender and Age Influence Nasal Soft Tissue Widening After Bone-Borne Transpalatal Distraction?
2022, Journal of Oral and Maxillofacial Surgery
Widening of the nasal soft tissue after transpalatal distraction (TPD) is a well-known consequence of this treatment method used to correct transverse maxillary deficiency. However, because literature is scarce about the influence of gender and age, the purpose of this study is to estimate changes in the nasal soft tissue after TPD and to measure the association of gender and age with these observed changes.
In this retrospective cohort study, patients with transverse maxillary deficiency underwent combined orthodontic-surgical treatment. Maxillary and nasal anatomical landmarks were compared using superimposed cone beam computed tomography images preoperatively and approximately 1 year postoperatively. Measurements included nasal soft tissue, nasal skeletal, and maxillary parameters. Significant differences in nasal soft tissue changes were correlated with patient gender, age, maxillary, and nasal skeletal changes using regression models.
Ninety one patients were included of which 33 were men (36%) and 58 women (64%). Independent of the maxillary widening, the mean nasal soft tissue widening was limited to 2 mm. Nasal soft tissue expansion was 60% to 80% of the nasal skeletal width and 25% to 31% of the skeletal maxillary width. The alar nasal base increased approximately 57% more than the alar nasal width.
Significant gender-related differences in nasal soft tissue widening were observed. Age-related differences were identified only as a trend. Small age-related and gender-related differences may not be relevant clinically since there are no established threshold values to assess a layperson's perception of nasal width variations. Technical and/or aesthetic concerns regarding TPD surgery can be addressed without patient's gender and/or age consideration.
Endoscopically-assisted surgical expansion (EASE) for the treatment of obstructive sleep apnea
2019, Sleep Medicine
The aim of this retrospective study was to evaluate the results of an outpatient surgical procedure known as endoscopically-assisted surgical expansion (EASE) in expanding the maxilla to treat obstructive sleep apnea (OSA) in adolescent and adults.
Thirty-three patients (18 males), aged 15–61 years, underwent EASE of the maxilla. All patients completed pre- and post-operative clinical evaluations, polysomnography, questionnaires (Epworth Sleepiness Scale [ESS] and Nasal Obstruction Septoplasty Questionnaire [NOSE]) as well as cone beam computed tomography (CBCT).
With EASE, the overall apnea hypopnea index (AHI) improved from 31.6 ± 11.3 to 10.1 ± 6.3. The oxygen desaturation index (ODI) improved from 11.8 ± 9.6 to 1.8 ± 3.7, with reduction of ESS scores from 13.4 ± 4.0 to 6.7 ± 3.1. Nasal breathing improved as demonstrated by reduction of the NOSE scores from 57.8 ± 12.9 to 15.6 ± 5.7. Expansion of the airway from widening of the nasal floor was consistently evident on all postoperative CBCT; the anterior nasal floor expanded 4.9 ± 1.2 mm, posterior nasal floor expanded 5.6 ± 1.2 mm, and the dental diastema created was 2.3 ± 0.8 mm. Mean operative time was 54.0 ± 6.0 min. All patients with mild to moderate OSA were discharged the same day; patients with severe OSA were observed overnight. All patients returned to school or work and regular activities within three days.
EASE is an outpatient procedure that improves nasal breathing and OSA by widening the nasal floor in adolescents and adults. Compared to current surgical approaches for maxillary expansion, EASE is considerably less invasive and consistently achieves enlargement of the airway with minimal complications.
Surgically assisted rapid maxillary expansion with bone-borne versus tooth-borne distraction appliances—a systematic review
2019, International Journal of Oral and Maxillofacial Surgery
The objective was to test the hypothesis of no difference in skeletal and dental arch expansion and relapse after surgically assisted rapid maxillary expansion with a bone-borne compared with a tooth-borne appliance. The PubMed, Embase (Ovid), Cochrane Library, and Google Scholar databases were searched in combination with a hand-search of relevant journals up until December 2017. No language restriction was applied. Two short-term randomized controlled trials with a low risk of bias fulfilled the inclusion criteria. No meta-analysis could be performed due to considerable heterogeneity. There were no statistically significant differences in the skeletal and dental arch expansion and relapse. Dental arch expansion was significantly greater than skeletal expansion with both treatment modalities. However, dissimilar evaluation methods, different outcome measures, unknown vertical level of force application with the bone-borne devices, and various methodological confounding factors posed serious restrictions to reviewing the literature in a quantitative systematic manner. Hence, conclusions drawn from the results of this systematic review should be interpreted with caution. Further well-designed long-term randomized clinical trials including a standardized protocol and three-dimensional analysis of the level of force application and morphological outcome are therefore needed before one treatment modality can be considered superior to the other.
Bone-borne surgically assisted rapid maxillary expansion: A retrospective three-dimensional evaluation of the asymmetry in expansion
2018, Journal of Cranio-Maxillofacial Surgery
Asymmetrical expansion occurs in patients treated with Surgically Assisted Rapid Maxillary Expansion (SARME). In the clinical setting, this asymmetrical expansion is seen in multiple directions. However, the frequency, actual directions and amount of asymmetry are unclear. Hence, the aim of this study was to analyze the directions and amount of asymmetrical lateral expansion in non-syndromic patients with transversal maxillary hypoplasia on employing bone-borne transpalatal distraction by means of SARME. Treatment involved corticotomies of all four bony supports, including pterygomaxillary disjunction.
A retrospective case series was formed from patients treated with SARME. Pre- and postdistraction Cone Beam Computed Tomography scans were superimposed. A reference frame was created to analyze lateral expansion asymmetries in five directions.
Clinical relevant asymmetries (>3.0 mm) in at least one of the investigated directions occurred in 55% of the patients. Lateral expansion asymmetries occurred mostly in the inferior-anterior part between the left and right segment and asymmetry in total expansion was noted between the anterior and posterior part of the maxilla.
This study confirms the clinical suspicion that using SARME with a bone-borne distractor and pterygomaxillary disjunction to treat non-syndromic patients with transversal maxillary hypoplasia, results in regular asymmetrical lateral expansion.

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^*: ^aClinical Research Fellow in Maxillo-Facial Surgery, General Hospital St. John, and Senior Resident in Maxillo-Facial Surgery, University of Rome “La Sapienza.”

^**: ^bConsultant in Maxillo-Facial Surgery, General Hospital St. John.

^*: The authors do not own stock in Surgi-Tec NV. Dr Mommaerts is a scientific consultant to that company and owns the patent on the TPD.

^**: The Clinical Research Fellowship was sponsored by the National Research Council (CNR) of Italy.

^*: Reprint requests to: Dr M. Mommaerts, Division of Maxillo-Facial Surgery, AZ St. Jan, Ruddershove 10, B-8000 Brugge, Belgium; e-mail, [email protected].

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Original ArticlePosterior transpalatal distraction with pterygoid disjunction: A short-term model study*,**,*,**,*

Abstract

Section snippets

Material and methods

Results

Discussion

Conclusions

Acknowledgements

Br J Oral Maxillofac Surg

Am J Orthod

Am J Orthod

Am J Orthod

Am J Orthod

Am J Orthod Dentofacial Orthop

Am J Orthod

Am J Orthod

J Oral Maxillofac Surg

J Oral Maxillofac Surg

J Craniomaxillofac Surg

Am J Orthod

Original Article
Posterior transpalatal distraction with pterygoid disjunction: A short-term model study*,**,*,**,*