Mandibular midline distraction using a tooth-borne device and a minimally invasive surgical procedure

Hybrid mandibular Bologna midline distractor in combination with surgically assisted rapid maxillary expansion for transverse facial expansion: clinical and cephalometric results

Transverse maxillomandibular hypoplasia can be treated with surgically assisted rapid maxillary expansion (SARME) in association with mandibular symphyseal distraction (MSD). This paper introduces a hybrid mandibular Bologna midline distractor (BMD); the effectiveness of the distractor in combination with SARME for the treatment of transverse skeletal deficiency was evaluated. This two-centre study included 10 patients with a transverse arch width deficit>7 mm and dental crowding, in both the maxilla and mandible, treated with SARME and MSD. The study design was partly retrospective (seven patients) and partly prospective (three patients). Frontal and lateral cephalometric analyses, as well as measurements on dental models, were performed at three different times: before treatment, after the distraction, and 6 months after postoperative orthodontic treatment. The cephalometric analyses and measurements on dental impressions confirmed a balanced and stable skeletal and dental mandibular expansion. An average symphyseal expansion of 7.8 mm was obtained, resolving dental crowding without dental extractions. In conclusion, mandibular expansion performed with the BMD in combination with SARME appears to be a viable surgical approach to transverse maxillomandibular hypoplasia. This technique allows the surgeon to obtain a balanced skeletal and dental expansion, with a low level of relapse.

Mandibular symphyseal distraction osteogenesis: 20 years of experience treating transverse deficiencies with an internal hybrid device

INTRODUCTION

Transverse mandibular deficiency has been traditionally managed by orthodontic compensation. However, without resolving the underlying skeletal hypoplasia it leads to high relapse rates. Few studies have reviewed the long-term experience and potential complications of mandibular symphyseal distraction osteogenesis (MSDO) as an alternative treatment method.

MATERIALS AND METHOD

A retrospective review of 20 patients (range: 4-19 years; mean: 11.9 years) treated with a hybrid MSDO device over the period of 1996-2017 was conducted. Epidemiological data, medical and dental history as well as photographic and cephalometric analyses were carried out. Furthermore, pre-operative and long-term post-operative status including dental occlusion and tooth-jaw discrepancies were recorded.

RESULTS

The distraction amount ranged from 3 mm to 15 mm (mean: 10 mm) with an average distraction period of 30.9 days. In long-term follow-up (mean: 7.3 years), 14 patients presented a class I and 6 patients presented a class II relationship. Correction of overjet, tooth jaw discrepancy and arch length discrepancy were obtained in 18, 20 and 17 cases respectively. A device malfunction was experienced in 6 patients.

CONCLUSION

Mandibular widening using a hybrid MSDO device can be efficiently and safely performed in a paediatric population. Further studies confirming our results and analysing facial aesthetic outcomes are warranted.

Mandibular Midline Distraction Osteogenesis with a Bone-borne, Tooth-borne or Hybrid Distraction Appliance: a Systematic Review

Objectives

The objective of the present systematic review was to assess the transverse skeletal and dental arch expansion and relapse after mandibular midline distraction osteogenesis with a bone-borne, tooth-borne or hybrid distraction appliance.

Material and Methods

A MEDLINE (PubMed), Embase and Cochrane library search in combination with a hand-search of relevant journals was conducted. Human studies published in English until the 3^rd of July, 2018 were included.

Results

Two comparative and seven non-comparative studies characterized by high risk of bias fulfilled the inclusion criteria. Transverse mandibular widening was achieved with the different types of distraction appliance displaying a horizontal V-shaped opening with larger anterior transverse expansion declining progressively towards the posterior part of the mandible. Bone-borne and hybrid appliance facilitate more skeletal expansion compared with tooth-borne appliance, whereas comparable dental arch expansion was achieved with the different types of distraction appliance. Skeletal and dental arch relapse with the different type of appliance was limited and comparable. However, frequency of complications was higher with bone-borne appliance compared with tooth-borne or hybrid appliance.

Conclusions

Mandibular midline distraction osteogenesis with bone-borne, tooth-borne or hybrid distraction appliance is an effective treatment modality to correct severe transverse mandibular discrepancies, although the skeletal and dental arch expansion pattern was dissimilar with the different types of appliance. However, dissimilar evaluation methods, different outcome measures, various methodological confounding factors posed serious restrictions reviewing the literature in a quantitative systematic manner. Hence, well-designed long-term randomized controlled trials applying three-dimensional technology, patient-related outcome measures and an economic perspective are needed before definite conclusions can be provided.

[Symphyseal bone distraction (part 2): which protocol in 2018? A systematic literature review]

INTRODUCTION

The aim of this systematic literature review is to propose a clinical protocol in 2018 by comparing therapeutic efficacy and undesirable effects of the technique.

MATERIALS AND METHODS

Searches were made on Pubmed/Medline and Cochrane for randomized clinical trials and case series involving mandibular symphyseal distraction over the past 20 years with a patient sample greater than or equal to 10.

RESULTS

Of the 92 articles, 25 met the inclusion criteria. A controlled trial was selected, but no randomized trial. The other studies were all case series, 16 retrospective and 8 prospective. Dental crowding over 7 mm, with or without compensation, is an indication for mid-symphyseal distraction. Pre-surgical orthodontic treatment ensures root divergence between the mandibular incisors. Tooth-borne devices are recommended in first intention. Surgical intervention (ambulatory) under local anesthesia and intravenous sedation is considered. The latency period before activation of the jack is 6 days. Activations are performed by the orthodontist and subsequently by the patient at a rate of 1 mm per day, with four activations daily. Orthodontic movements are resumed two weeks after activations are discontinued. The distractor is removed within two to three months after installation.

CONCLUSION

Although the main features of the mid-symphyseal distraction protocol were drawn up essentially in the light of expert opinion, they still need to be refined by controlled trials.

Minimally invasive orthognathic surgery: a systematic review

Minimally invasive techniques are currently applied in many oral and maxillofacial surgical procedures, including orthognathic surgery. A systematic review on the application of potentially minimally invasive procedures in orthognathic surgery was performed to provide a clear overview of the relevant published data. Articles in English on minimally invasive orthognathic procedures, published in the scientific literature, were obtained from the PubMed, Embase, and Cochrane Library databases, and an additional manual search (revised 31 December 2016). After screening the abstracts and applying the eligibility criteria, 403 articles were identified. All articles reporting the potential for minimally invasive orthognathic surgery were included (n=44). The full papers were evaluated in detail and categorized as articles on a minimally invasive surgical approach (n=4), endoscopically assisted orthognathic procedures (n=17), or the use of a piezoelectric device in orthognathic surgery (n=25); two articles were each included in two categories. Although a small incision and minimal dissection is the basic principle of a minimally invasive technique, most articles (90.9%) reported the endoscope and piezoelectric instrument as important tools in minimally invasive orthognathic surgery. Evidence from available studies suggests that patients undergoing minimally invasive orthognathic surgery have less morbidity and make a faster recovery. Further research should aim to obtain higher levels of evidence.

New Technique for Mandibular Symphyseal Distraction by a Double-Level Anchorage and Fixation System: Advantages and Results

INTRODUCTION

A surgical technique to widen the mandible is the mandibular midline distraction: the most common indications for mandibular midline distraction are severe mandibular anterior crowding, severe mandibular transverse deficiency, uni- or bilateral crossbite, impacted anterior teeth with inadequate space, and tipped teeth. Commonly used distraction devices can be divided into 2 systems: bone-borne distraction system appliance, dental-borne distraction systems. Each system has peculiar advantages, disadvantages, and different indications. To combine advantages of both systems we developed a new technique adopting an immediate basal bone widening with fixation after osteotomy and a dental borne rigid lingual system for distraction.

AIM

The aim of this work is to show a new technique for symphysis mandibular distraction based on a double-level anchorage and fixation system on clinical patients showing final results and advantages.

METHODS

Two patients affected by dento-alveolar and basal bone maxillary and mandibular transversal collapse even in association with other skeletal malocclusion were selected. Patients were clinically and radiographically studied and analyzed at different times before and after surgery. Dental and basal bone measurements were performed clinically and radiographically.

RESULTS

The results were optimal with perfect dental arches alignment followed by closing of the open bites with multiple-segmented surgery in a second surgical time. No misalignment of the 2 mandibular halves was noticed during the distraction procedure.

DISCUSSION

Dental-bone discrepancies correction is mandatory before orthodontic treatment alignment. Transversal jaw expansion can be achieved safely and stably by distraction of both maxillae for the combination of osteogenesis and histogenesis with augmentation of both bone and soft tissue. Bone-borne distraction will result in more stable results; dental-borne devices will result in more simple and aesthetically rewarding procedures. Hybrid techniques usually show mixed results depending on the characteristics of the device. For this reason we developed a combination of both the aforementioned systems which is not a hybrid system but the combination of an immediate expansion of the symphysis and fixation by 1 miniplate with only 2 screws acting like hinges during distraction, combined with a lingual distraction system at the alveolar bone level.

CONCLUSIONS

Bone-borne distraction systems result in more efficient basal bone mandibular widening with increased stability for dental results. For dental-borne appliance the advantages consist in no second surgery need for their removal, no transmucosal hardware emergence and better aesthetic, especially when lingual devices were used. Our technique combines advantages of both procedures.

Minimally Invasive Genioplasty Procedure

In this technical note, we present a new surgical approach for genioplasty in which a minimally invasive procedure is used to perform the chin osteotomy. The main goal was to reduce postoperative functional recovery time and possible complications, especially reduction of lip incompetence, chin ptosis, and muscle dysfunction, by retaining the intactness of the mentalis muscles.

Facial improvement after mandibular midline distraction and surgically assisted rapid maxillary expansion

This case report describes the retreatment of a 49-year-old woman with severe crowding in the mandibular incisor region and tapered maxillary and mandibular arches. Treatment consisted of mandibular midline distraction and surgically assisted rapid maxillary expansion to increase arch length. The need for proper presurgical orthodontics is described, and the complications during treatment are discussed. The results of treatment, including the superimposition of 3-dimensional facial scans, are presented. The treatment approach we used is typically indicated for patients with previous extractions of all first premolars who develop significant crowding after treatment. Surgical planning in 3 dimensions and the use of a 3-dimensional designed surgical osteotomy guiding wafer should improve the predictability of this treatment approach.