Pre-autotransplantation alveolar process augmentation and premolar autotransplantation as a treatment method for single tooth replacement in adolescents.

The treatment of young patients with missing teeth and an atrophied alveolar process after trauma or agenesis of a tooth can be challenging. The aim of this study was to evaluate autotransplantation of a premolar after pre-autotransplantation alveolar process augmentation (PAPA) as a treatment option for these patients. A retrospective cohort study was implemented to analyse the PAPA procedure and subsequent autotransplantation procedure. Alveolar process augmentation was performed using different types of autologous bone grafts. Subsequent autotransplantation of one or more premolars was performed approximately 4 months later. Nine patients with a mean age of 12 years were included. Twelve premolars were transplanted after a PAPA procedure: seven in the maxillary incisor region, four in the mandibular premolar region, and one in the mandibular incisor region. Initially all transplanted teeth functioned well. However, one mandibular premolar that was transplanted in the maxillary incisor region was lost because of resorption after 6 years of follow-up. The other 11 transplanted teeth functioned well. The mean follow-up was 6 years (range 3-13 years). The results showed that autotransplantation can be facilitated by PAPA with a high chance of success. It can therefore be a valuable addition to other existing treatment options.

[Multidisciplinary treatment of amelogenesis imperfecta]. / Multidisciplinaire behandeling van amelogenesis imperfecta.

A healthy 13-year-old patient with amelogenesis imperfecta was referred by her orthodontist to the joint consultation hour (Center for Specialised Dentistry and Oral and Maxillofacial Surgery). In addition to her amelogenesis imperfecta, she was diagnosed with a class 2 malocclusion and a mandibular hypoplasia. She was treated successfully through a multidisciplinary approach.

[Surgical uprighting of partially impacted second molars]. / Chirurgisch oprichten van deels geïmpacteerde tweede molaren.

Eruption of mandibular second molars usually occurs around the age of 12. Incomplete eruption of second molars in such young patients can lead to loss of the molars, due to caries, root resorption or periodontal pathology. When a pathology of this kind develops, the treatment option for a mesially impacted molar is often to extract the tooth. If tooth eruption is, however, monitored closely by the dentist and/or orthodontist, early treatment can be considered in order to preserve the tooth. Partially impacted second molars can be placed in a functional anatomical position by surgical uprighting and repositioning. As long as certain conditions are met, this results in sound functionality with preservation of the full dentition. In cases of incomplete eruption, this treatment option should therefore be considered by dentists and orthodontists before extracting the second molars.

Density of the mandibular ramus (cancellous:cortical bone volume ratio) as a predictor of the lingual fracture pattern in bilateral sagittal split osteotomy.

The aim of this retrospective cohort study was to evaluate the relative amount of cancellous bone in the mandibular ramus as a predictor of lingual fracture patterns after bilateral sagittal split osteotomy (BSSO). The study including 78 consecutive patients (156 osteotomy sites). In preoperative cone-beam computed tomographic (CT) scans, the volumes of cancellous and cortical bone in the BSSO surgical field were estimated. Patients were divided into two groups based on the cancellous:cortical bone ratio. We studied postoperative cone-beam CT scans for lingual fracture lines and subcategorised them according to the lingual split scale (LSS). Generalised linear mixed models (GLMM) were estimated to evaluate the association between the cancellous:cortical bone ratio and the lingual fracture pattern. There was a significant association between the cancellous:cortical bone ratio of the mandibular angle and the lingual fracture pattern after BSSO. Mandibular angles with a relatively small amount of cancellous bone showed significantly more LSS3 fracture lines (OR=1.990, 95%CI 1.043 to 3.796, p=0.043). These mandibular angles also showed more unfavourable fractures (LSS4), although this was not significant (OR=2.352, 95%CI 0.748 to 7.392, p=0.143). The relative amount of cancellous bone in the mandibular angle is significantly associated with the lingual fracture line after BSSO.

Long-term outcomes 1-20 years after autotransplantation of teeth: clinical and radiographic evaluation of 66 premolars and 8 molars.

In this retrospective study we investigated the long-term survival of autotransplanted premolars and molars with incompletely developed roots. The presence of the transplanted teeth and their outcome after autotransplantation was ascertained from clinical and radiographic evaluation by a maxillofacial surgeon or dentist. Kaplan Meier survival curves were estimated for the total population and for the two groups (premolars and molars). Fifty-one patients with 74 transplanted teeth were included, and the median duration of follow-up was 10 (range 1-20) years. Four of 66 premolars and one of 8 molars were removed and the cumulative survival was 95.4% (95% CI 90.3 to 100). The difference in survival between the premolars and molars was not significant. These results show that the long-term survival of autotransplanted teeth is good. Replacement of a single tooth by autotransplantation should therefore always be considered and is preferred when a suitable donor tooth is available.

[A PhD completed. Bilateral sagittal split osteotomy: risk factors for complications and predictability of the splitter-separator technique]. / Serie: Hora est. De bilaterale sagittale splijtings­osteotomie: risicofactoren voor complicaties en voorspelbaarheid van de splijttang-splijtheveltechniek.

Bilateral sagittal split osteotomy (BSSO) is a surgical technique to correct hypoplasia, hyperplasia or asymmetry of the mandible. The risk of complications associated with BSSO with splitter and separators, the so-called splitter-separator technique, and the predictability of this technique were analysed. The average incidence of complications associated with classic BSSO techniques was determined by a review of the literature. With classic techniques, a bad split occurred in 2.3% of the operated sides, removal of osteosynthesis material on account of complaints in 11.2% of patients, and permanent neurosensory disturbances in the area of the mental nerve in 33.9% of patients. The incidence of complications for BSSO with splitter and separators is a bad split in 2.0% of the operated sides, necessary removal of osteosynthesis material in 5.6% of patients, and permanent neurosensory disturbances of the lower lip in 9.9% of patients. Removal of the third molars during BSSO may result in an increased chance of bad split but does not increase the risk of other complications. In conclusion, BSSO with splitter and separators is a reliable technique, with a remarkably low incidence of permanent neurosensory disturbances of the lower lip.

[Replacing heavily damaged molars with the use of 3D-techniques]. / Vervanging van ernstig beschadigde molaren met behulp van 3D-technieken.

Seriously damaged molars can be replaced by autotransplantation with the help of 3D techniques. In the present case, involving an 18-year old patient, 18, 38 and 48 were used to replace, respectively, 14, 36 and 37. Preoperatively, the width of the crowns and the root development of 18, 38 and 48 were analysed using 3D imaging. During the autotransplantation procedure, the new alveoli are formed with the help of replicas of the donor molars printed in 3D, in order to prevent iatrogenic damage to the actual donor molars.. The extra-alveolar time was less than 2 minutes for all donor molars. Postoperative follow-up showed physiologic integration of the transplanted molars. There was no ankylosis. Autotransplantation with the help of 3D techniques makes it possible to perform complex procedures with good results.

[Incision of the third molar in the Netherlands. Incision tech-niques for the removal of impacted third molars in the mandible.] / Incisietechnieken bij verwijdering van geïmpacteerde derde molaren in de onderkaak.

Various incision techniques to remove impacted third molars in the mandible have been described, for example, the flap incision, the envelope incision, the distal incision and the modified envelope incision. The aim of this study was to record the incision techniques used by oral and maxillofacial surgeons in the Netherlands for the removal of impacted third molars in the mandible. All members of the Dutch Association of Oral and Maxillofacial Surgery (NVMKA) received a questionnaire. In this questionnaire, the surgeons specified their standard incision technique for the removal of, respectively, mesially impacted, upright, or distally impacted mandibular third molars. Of the 323 questionnaires sent, 172 were returned (53,3% response rate). The flap incision and the distal incision were the most frequently used incisions by oral and maxillofacial surgeons (including residents) in the Netherlands. The academic centre seems to have a lasting impact on the preferred way of removing an impacted third molar. It also seems that an oral and maxillofacial surgeon more frequently removes a third molar in the mandible from a sitting position than a resident.

Autotransplantation of teeth using computer-aided rapid prototyping of a three-dimensional replica of the donor tooth: a systematic literature review.

This systematic review provides an overview of studies on autotransplantation techniques using rapid prototyping for preoperative fabrication of donor tooth replicas for preparation of the neo-alveolus. Different three-dimensional autotransplantation techniques and their treatment outcomes are discussed. The systematic literature search yielded 19 articles that satisfied the criteria for inclusion. These papers described one case-control study, four clinical observational studies, one study with a clinical and in vitro part, four in vitro studies, and nine case reports. The in vitro studies reported high accuracy for the printing and planning processes. The case reports all reported successful transplantation without any pathological signs. The clinical studies reported a short extraoral time of the donor tooth, with subsequent success and survival rates of 80.0-91.1% and 95.5-100%, respectively. The case-control study reported a significant decrease in extraoral time and high success rates with the use of donor tooth replicas. In conclusion, the use of a preoperatively designed surgical guide for autotransplantation enables accurate positional planning, increases the ease of surgery, and decreases the extraoral time. However, the quality of the existing body of evidence is low. Further research is therefore required to investigate the clinical advantages of this innovative autotransplantation technique.

Are there risk factors for osseous mandibular inferior border defects after bilateral sagittal split osteotomy?

PURPOSE: Bone defects of the inferior mandibular border (osseous inferior border defects) can cause unesthetic postoperative outcomes after bilateral sagittal split osteotomy (BSSO). The aim of this study was to estimate the frequency of osseous inferior border defects after BSSO and to identify risk factors for this complication. MATERIALS AND METHODS: This retrospective study included consecutive patients who underwent BSSO for mandibular retrognathia. The primary outcome was the presence/absence of osseous inferior border defects. Predictors included the mandibular movement, rotation of the occlusal plane, postoperative proximal segment position, pattern of lingual fracture, occurrence of bad split, and presence of third molars. RESULTS: The study sample consisted of 200 patients and had a mean follow-up of 13 months. The mean mandibular advancement and rotation was respectively 5.8 mm and 5.4° clockwise. Osseous inferior border defects were present in 7.0% of splits and in 12.5% of patients. Significant risk factors for inferior border defects included increased advancement, increased clockwise rotation, cranial rotation of the proximal segment, and a split originating in the lingual cortex. CONCLUSION: In conclusion, osseous inferior border defects occur significantly more often in cases with large mandibular advancement, increased clockwise rotation of the occlusal plane, malpositioning of the proximal segment, and a split originating in the lingual cortex.

[The 3D printed drilling template for bilateral sagittal osteotomy]. / De 3D-geprinte boormal voor de bilaterale sagittale splijtingsosteotomie.

The bilateral sagittal osteotomy (BSSO) is a widely used surgical technique within orthognatic surgery. The specific osteotomy design may vary from clinic to clinic. The best position of the bone cuts in a BSSO continues to be a point of discussion and probably differs from patient to patient. In addition, standardisation in, for example, research may be desirable. Pre-operative planning using a drilling template in order to position the planned individual saw cuts during BSSO can be of value. To achieve this goal, a pre-operative 3D printed biocompatible drilling template was manufactured for 1 patient on the basis of pre-operative planning. The difference between the pre-operatively determined bone cuts with the assistance of the drilling template and the actual bone cuts was still large.

[Autotransplantation 2.0. Considerations, results and the latest techniques]. / Autotransplantatie 2.0. Overwegingen, uitkomsten en nieuwste technieken.

Autotransplantation is a valuable technique offering a physiological type of tooth replacement to patients with missing teeth. Teeth with open apices (50-75% apical closure) will regenerate with vitality following autotransplantation. The success rate following an autotransplantation is 82%. The remaining 18% can usually still be treated successfully with a simple additional treatment. The tooth survival rate 10 years after autotransplantation is higher than 90%. The use of 3D techniques makes it possible to create a pre-operative replica of the donor tooth. With this, a new alveolus can be prepared at the transplant site even before extraction. This technique reduces the extra-alveolar time for the donor tooth and minimises the possibility of iatrogenic damage. This results in a streamlined procedure, enabling better planning with better results.

A Novel Approach for Computer-Assisted Template-Guided Autotransplantation of Teeth With Custom 3D Designed/Printed Surgical Tooling. An Ex Vivo Proof of Concept.

PURPOSE: The aim of this study was to introduce a novel method for accurate autotransplantation with computer-assisted guided templates and assembled custom-designed surgical tooling and to test the feasibility and accuracy of this method ex vivo. MATERIALS AND METHODS: A partially edentulous human mandibular cadaver was scanned with a cone-beam computed tomography (CBCT) system and an intraoral scan system. The 3-dimensional (3D) data of this cadaver were imported into specialized software and used to analyze the region of the recipient site and the donor tooth was selected. Subsequently, congruent to the donor tooth, custom surgical tools and a surgical guided template were designed and 3D printed. The guided osteotomy was performed and the donor tooth was transplanted. To evaluate the planned position of the donor tooth in relation to the position of the transplanted donor tooth, the mandible with the transplanted donor tooth was rescanned with the CBCT system and software matching was applied to measure the accuracy of the procedure. RESULTS: The angular deflection of the transplanted donor tooth in relation to the planned donor tooth position was 3.1°. When comparing the 3D positions of the shoulder, there was a deviation of 1.25 mm and an apical deviation of 0.89 mm. CONCLUSION: With the use of currently available technology, it is feasible to accurately plan and create in a virtual simulation a donor tooth position with congruent custom surgical tools and to transfer this to a clinical setting with 3D printing. However, further research on multiple levels is needed to explore this novel approach.

Incidence and recovery of neurosensory disturbances after bilateral sagittal split osteotomy in different age groups: a retrospective study of 263 patients.

This study aimed to investigate the incidence of neurosensory disturbance (NSD) after bilateral sagittal split osteotomy (BSSO) in different age groups and to assess the probability of sensory recovery in patients aged <19 years, 19-30 years, and >30 years. Hypoaesthesia of the lower lip was assessed subjectively and objectively immediately after BSSO and at 1 week and 1, 6, and 12 months after BSSO. Hypoaesthesia was considered permanent if it was present 1 year after BSSO. The frequency of NSD immediately after surgery was significantly higher in older patients. The cumulative incidence of recovery at 1 year was lower and the mean time to recovery was longer in the older patients, although these differences were not statistically significant. Older age was a significant risk factor for permanent hypoaesthesia, with an incidence of 4.8% per patient aged <19 years, 7.9% per patient aged 19-30 years, and 15.2% per patient aged >30 years. These findings show that the risk of NSD after BSSO is significantly higher in older patients. These results may aid surgeons in preoperative patient counselling and in deciding the optimal age at which to perform BSSO.

Bilateral sagittal split osteotomy in a mandible previously reconstructed with a non-vascularized bone graft.

We report a bilateral sagittal split osteotomy (BSSO) in a reconstructed mandible. A 28-year-old woman underwent a segmental mandibulectomy due to a multicystic ameloblastoma in the left jaw. After primary plate reconstruction, final reconstruction was performed with a left posterior iliac crest cortico-cancellous autograft. Due to a pre-existing Class II malocclusion, the patient was analyzed for combined orthodontic-surgical treatment. Subsequently, after 1 year of orthodontic treatment, the BSSO was planned. The sagittal split was performed in the remaining right mandible and on the left side in the iliac crest cortico-cancellous autograft. Ten months later, oral rehabilitation was completed with implant placement in the neomandible. Follow-up showed a Class I occlusion, with good function. The patient was very satisfied with the functional and aesthetic results. This case shows that a BSSO can be performed in a reconstructed mandible, without side effects and with good functional and aesthetic results.