Dental implants as risk factors for patients with medication-related osteonecrosis of the jaws (MRONJ).

An increasing number of patients with medication-related osteonecrosis of the jaws (MRONJ) has recently been reported. It is still being debated whether the presence or placement of dental implants can lead to MRONJ, so the aim of this study was to find out whether dental implants are a risk factor for MRONJ. From January 2003-January 2019 180 patients with MRONJ were seen at the Leiden University Medical Center. Luxating moments for the onset of MRONJ were calculated retrospectively. We collected clinical data and details of antiresorptive medication and found 22 patients with both dental implants and MRONJ. In 18 patients the implants were in the region of the MRONJ and they were included in this study, 14 who had had implants before using antiresorptive drugs and four who had had antiresorptive drugs before or at the time that the implants were placed. The median times between the placement of implants and the diagnosis of MRONJ in these two groups were 24 months and 6 months, respectively. Among the 47 implants, 30 were located in the necrotic region, and all 30 were either lost spontaneously or had to be removed during treatment of MRONJ. Our results show an increased risk for developing MRONJ in patients with dental implants. Both peri-implantitis around previously placed implants, and insertion of dental implants, are risk factors. Prevention of peri-implantitis and caution when inserting dental implants in patients who take antiresorptive medication are therefore important.

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.

Outcome of different treatments for chronic diffuse sclerosing osteomyelitis of the mandible: a systematic review of published papers.

Treating chronic diffuse sclerosing osteomyelitis (DSO) is challenging and many treatments have been reported. However, we know of no standard protocol or guidelines. In this systematic review of relevant publications we provide an overview of the different treatments used. We made an electronic search of PubMed, Medline, Embase, Web of Science, and the Cochrane Library databases, for papers that described the treatment of DSO of the mandible. The search yielded 48 papers that applied to all inclusion criteria, resulting in 16 case reports, 13 case series, 18 retrospective clinical cohort studies, and one randomised controlled trial. Reported treatment options included different operations; the use of antibiotics, anti-inflammatories, and antiresorptive medication; conservative treatment; and hyperbaric oxygen. Surgical treatment resulted in a low success rate and was associated with higher morbidity than other treatments. Conservative treatment, and that of bisphosphonates, yielded more promising results, so conservative treatment and bisphosphonates seem to be the most promising therapeutic options. However, because of the high risk of bias, no firm conclusions can be drawn, and larger studies with clear inclusion criteria and specified endpoints are needed.

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.

[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.

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 cadaveric pig mandibles: evaluation of the lingual fracture line based on the use of splitters and separators.

OBJECTIVE: To analyze the splitting pathways of the (lingual) fracture lines during a bilateral sagittal split osteotomy (BSSO) in cadaveric pig mandibles. STUDY DESIGN: A BSSO was performed using splitters and separators. Special attention was paid to end the horizontal medial cut at the deepest point of the entrance of the mandibular foramen. RESULTS: Of all lingual fractures, 95% ended in the mandibular foramen. Forty percent of these fractures extended through the mandibular canal and 40% extended inferiorly along the mandibular canal. CONCLUSION: Almost all lingual fracture lines ended in the mandibular foramen, most likely due to the placement of the medial cut in the concavity of the mandibular foramen. The mandibular foramen and canal could function as the path of least resistance in which the splitting pattern is seen. We conclude that a consistent splitting pattern was achieved without increasing the incidence of possible sequelae.

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.

Skeletal stability after mandibular advancement in bilateral sagittal split osteotomies during adolescence.

Bilateral sagittal split osteotomy (BSSO) is the most frequently performed surgery for correcting mandibular retrognathia. Few studies have reported the use of BSSO in young patients, as growth may cause relapse. The aim of the present study was to determine the amount of relapse after performing BSSO in patients aged less than 18 years. Patients who had a mandibular advancement by BSSO surgery between January 2003 and June 2008 were evaluated. Eighteen patients were treated before the age of 18 years and compared with patients treated at 20-24 years of age. Cephalometric radiographs were used to determine the amount of relapse. For patients aged less than 18 years, the mean horizontal relapse after 1 year was 0.5 mm, (10.9% of perioperative advancement). For patients aged 20-24 years, the mean relapse was 0.9 mm, (16.4% of perioperative advancement). There were no significant differences between the age groups (p > 0.05). In conclusion, the BSSO procedure is a relatively stable procedure, even during adolescence.

[Automutilation of the palate in a psychiatric patient]. / Automutilatie van het palatum bij een psychiatrische patiënt.

A 46-year-old man with a history of alcohol abuse was referred to an oral and maxillofacial surgeon with a large necrotic wound with raised edges on the palate. After history taking, radiography and clinical assessment, together with a psychiatrist, the lesion was diagnosed as an automutilation resulting from a period of alcohol abstinence. After a period of care in a medical centre, the lesion improved quickly. Following this treatment, the patient was admitted to a psychiatric treatment centre for supplemental treatment of his addiction problems.

An atypical presentation of a solitary bone cyst of the mandibular ramus: a case report.

This report describes a large solitary bone cyst involving the mandibular ramus, presenting with a history of recurrent hypoaesthesia of the lower lip and a multilocular, multilobular radiological aspect with cortical expansion and possibly cortical perforation.

[Plastic surgery of oroantral perforations superfluous in the future?]. / Antrumplastiek in de toekomst overbodig?

An oroantral perforation can occur with the extraction of a premolar or molar in the upper jaw. Small perforations with a deep extraction alveolus can be treated using sutures only; larger perforations are treated surgically, using a buccal sliding or palatal flap. The distinction between small and large perforations can be difficult to make. As a result, oroantral perforations are usually treated by plastic closure. This pilot study presents a new, simple, time-reducing method for the treatment of oroantral perforations using a biodegradable membrane without primary closure of the wound. Six patients with a positive nose-blowing test after extraction were treated according to the new method. In all 6 patients the oroantral perforation was closed after 2 weeks and each showed adequate wound healing after 6 weeks. More research is needed to confirm the results of this preliminary study and the use of this technique on larger perforations.

[Child abuse]. / Kindermishandeling.

It is estimated that in the Netherlands over 100.000 children per year are victims of child abuse. In more than 50% of the cases of physical abuse there is a trauma of the head and neck area. Therefore, it is likely that (without realizing it) dentists are regularly confronted with cases of child abuse. Dentists have an ethical duty to take positive action in cases of suspected child abuse. They may refer the patient to an oral surgeon, consult the family physician or ask the advice of the 'Advies- en Meldpunt Kindermishandeling' (Advice and Report Centre for Child Abuse). The Dutch Dental Association, the Dutch Association of Family Physicians and the Royal College of Physiotherapists have signed a formal agreement to promote closer cooperation in identifying child abuse more quickly.

Endoscopically assisted reduction of anterior table frontal sinus fractures.

AIMS: To present a retrospective series of six patients with endoscopically assisted reduction of anterior table frontal sinus fractures. MATERIALS AND METHODS: The patients with isolated anterior table fractures were treated between April 2005 and June 2006 in the Leiden University Medical Centre. In two of the six patients the procedure was performed under local anaesthesia. The endoscope was introduced via existing lacerations, an incision in a natural skin crease or just above the hairline. The fracture was reduced and if necessary fixed. RESULTS: In all patients restoration of the cosmetic deformity was achieved clinically. CONCLUSION: The use of endoscopes makes minimally invasive reduction of outer table fractures of the frontal sinus possible, even under local anaesthesia.