How reliable are follow-up studies on odontogenic keratocysts?

Follow-up studies on odontogenic keratocysts have reported widely varying recurrence rates. This raises the question of how reliable these studies are and how the results should be interpreted. The aim of this study was to critically assess the information from all follow-up studies published since 2004 against a set of criteria to determine how thorough the study was. These criteria include the exclusion of the orthokeratinized variant, exclusion of cysts associated with nevoid basal cell carcinoma syndrome, and appropriate reporting of dropouts. A search of four electronic databases covering the years 2004-2022 was performed. Only studies with a sufficient follow-up period (covering a range of 1-8 years) were included. Studies with fewer than 40 cases were excluded. Fourteen relevant studies were identified in the literature search. The vast majority of these studies had considerable shortcomings, giving rise to serious doubts about the validity of their recurrence rate results. Of note, these studies have often been included in meta-analyses that report on the best treatment options to reduce the tendency of recurrences. The results of this review strongly suggest that multicentre studies with strict protocols should be performed to advance knowledge of the presentation of recurrences, both the timing and frequency.

The odontogenic keratocyst revisited.

The treatment of odontogenic keratocysts is reviewed in light of the aetiology and pathogenesis of these lesions. The role of the dental lamina and submucosal hamartias, as frequently seen in nevoid basal cell carcinoma syndrome, is discussed, and the implications for treatment are emphasized.

The significance of recurrent odontogenic keratocysts in bone grafts.

A comprehensive literature review identified 10 reported cases of recurrent odontogenic keratocysts (OKCs) in bone grafts. Seven of them were sufficiently documented for further analysis. All except one of the patients had a long history of repeated recurrences. They were all approached via an extraoral route, avoiding a mucosal perforation, when the bone graft was placed after a segmental resection. In three cases, this was also true for the primary treatment. The origin of the recurrences is considered to be the oral mucosa, almost certainly involving the proliferation of epithelial islands or microcysts that were close to the original OKC. A plea is made to avoid segmental or marginal resections for this lesion and to pay attention to possible epithelial islands/microcysts in the overlying attached mucosa in the case where marsupialization is preferred.

Graeme Warrack: oral surgeon and war hero.

This paper describes the heroic efforts of Graeme Warrack, an oral surgeon, to save as many lives as possible during the battles around Arnhem in 1944. As the chief medical officer (CMO) of the medical section of the 1st British Airborne Division, he and his staff took care of many casualties, both on the battlefield and at the emergency hospital in Apeldoorn, north of Arnhem. He escaped from the hospital when all the patients were to be transported to prisoner of war (POW) camps in Germany, and was hidden by a Dutch family. Finally, with the help of the Dutch resistance movement, he was successfully ferried over the big rivers into liberated country.

A prospective epidemiological study on odontogenic tumours in a black African population, with emphasis on the relative frequency of ameloblastoma.

The persistent view in the literature is that the relative frequency of ameloblastomas is higher in the black population than in Caucasians. The aim of this study was to determine the relative frequency of all odontogenic tumours (OT) in a 100% black population and to compare our findings with those of previous studies. A prospective study was undertaken of all patients presenting with OT to all 16 Nigerian departments of oral and maxillofacial surgery over a 4-year period. The following data were obtained: patient demographics, delay to presentation, extent of the lesion, and histological diagnosis. Six hundred and twenty-two cases were studied. A slight male preponderance was observed (male to female ratio 1.17:1). Patients ranged in age from 5 to 89 years, with a peak incidence in the third decade. The relative frequency of OT was 0.99 per million and that of ameloblastoma was 0.76 per million. Ameloblastoma was the most prevalent OT (76.5%), followed by adenomatoid odontogenic tumours (5.6%), odontogenic myxoma (4.5%), and keratocystic odontogenic tumours (KCOT) (3.1%). The relative frequency of ameloblastoma among Nigerians was not different from frequencies reported previously among Caucasian and Tanzanian black populations. KCOTs were, however, rarely diagnosed in Nigerians as compared to the white population in the Western world.

Do the changes in muscle mass, muscle direction, and rotations of the condyles that occur after sagittal split advancement osteotomies play a role in the aetiology of progressive condylar resorption?

Changes in cross-sectional area (CSA), volume (indicating muscle strength), and direction of the masseter and medial pterygoid muscles after surgical mandibular advancement were measured, along with the rotation of the condyles after bilateral sagittal split osteotomies (BSSOs) to advance the mandible. Measurements were done on magnetic resonance images obtained before and 2 years after surgery. CSA and volume were measured in five short-face and seven long-face patients (five males, seven females). Muscle direction was calculated in eight short-face and eight long-face patients (eight males, eight females). Short-face patients underwent BSSO only; long-face patients underwent combined BSSO and Le Fort I osteotomies. The CSA and volume decreased significantly (mean 18%) in all patients after surgery. The postoperative muscle direction was significantly more vertical (9°) in long-face patients. Rotations of the proximal segments (condyles) were minimal after 2 years. The results of this study showed that, after BSSO advancement surgery, changes in the masseter and medial pterygoid muscles are not likely to cause increased pressure on the condyles and nor are the minimal rotations of the condyles. It is concluded that neither increased muscle traction nor condylar rotations can be held responsible for progressive condylar resorption after advancement BSSO.

Stability, complications, implant survival, and patient satisfaction after Le Fort I osteotomy and interposed bone grafts: follow-up of 5-18 years.

The results of a retrospective study on 24 patients who underwent a Le Fort I osteotomy to improve the condition for implant insertion are presented. They all had an edentulous maxilla, Cawood and Howell class VI. Bone grafts were taken from the anterior or posterior iliac crest and implants were placed between 3 and 6 months after the osteotomy. The follow-up period ranged from 5 to 18 years. Initial complications occurred in seven patients in whom small bony defects were present at the time of the implant insertion procedure. The position of the advanced and downward grafted maxilla remained stable over the years. A total of 135 implants were initially inserted, of which 34 failed over the years. Ten implants were inserted to compensate for lost ones, of which only one failed. The screw implants tended to do better than the cylindrical implants. Two patients lost all implants; they had undergone previous surgery affecting the sinus and were also heavy smokers. The remaining 22 patients were satisfied with their treatment as shown by visual analogue scale scores. The results presented are in keeping with those of other reports and underscore the viability of the procedure.

Lower border bone onlays to augment the severely atrophic (class VI) mandible in preparation for implants: a preliminary report.

We present the preliminary results of a study involving a group of consecutive patients who underwent lower border onlay grafting, limited to the symphyseal area, in preparation for implant insertion. This technique allows for maximum-sized implants, followed by prosthetic rehabilitation. The main advantage of this method is the minimal risk of damage to the mental nerve. Sixteen patients were followed for a period of 6 months to 4 years and all were free of neurosensory disturbances. Eight had a removable overdenture placed and were satisfied with the result. This surgical approach allows the patient to wear their dentures during the healing period. A further advantage of lower border grafting over intraoral upper border grafting is that mucosal dehiscences are not seen.

Immediate reconstruction of the mandible after resection for aggressive odontogenic tumours: a cohort study.

The results are reported of a clinical follow-up study on 32 selected but consecutive patients with mandibular ameloblastoma. They were all treated by a segmental resection and reconstructed, using two 2.3 mm reconstruction plates and an autogenous particulate bone graft, taken from the anterior iliac crest, and platelet rich plasma. Follow-up ranged from 12 to 39 months, with an average of 27.9 months. Undisturbed healing occurred in 29 patients, while three had postoperative infections, but in only one case did that result in failure of the graft. The patients' appreciation was measured using an adapted quality of life questionnaire. The results were compared with a similar group who did not undergo reconstruction. The eating of solid food, appearance and speech were considerably better in the reconstructed group. The conclusion is that this means of reconstruction is appropriate for patients with benign but aggressive odontogenic tumours of the mandible, particularly in developing countries, since the expenses seem to be affordable.

The influence of a Le Fort I impaction and advancement osteotomy on smile using a modified alar cinch suture and V-Y closure: a prospective study.

A previous report from the authors' department showed that a modified alar cinch suture combined with a muco-musculo-periosteal V-Y closure (mACVY) improves nasolabial mobility. To test if the improvements were equal to the range of nasolabial mobility in non-dysgnathic persons, a prospective study was carried out in 56 patients: 31 with mACVY, 25 with simple closing sutures (SCS) and 18 non-operated, angle class I volunteers. Standardized full facial frontal photographs, taken immediately preoperatively and 18 months postoperatively were used. The landmarks, alare, crista philtri and cheilion were analysed. The test has a standard deviation of 0.9 mm. Intra-group changes, paired t-test, and inter-group differences, unpaired t-test (p<0.05) were statistically analysed. The results show significant preoperative differences in nasolabial mobility compared with the control group, for both groups. Postoperative mobility improved in both groups, but significantly with mACVY with horizontal movement of cheilion and alare, and the vertical movement of crista philtri and less so for the vertical movement of crista philtri with SCS. Postoperative inter-group differences in mobility were small and significant for SCS vs the control group. It can be concluded that using mACVY improves orofacial movement to the level of normal class I volunteers.

The effect of platelet-rich plasma on early and late bone healing using a mixture of particulate autogenous cancellous bone and Bio-Oss: an experimental study in goats.

Platelet-rich plasma (PRP), containing various growth factors, may speed up wound and bone healing. Using osteoconductive alloplastic materials in reconstructive surgery, the amount of autogenous bone needed can be reduced. The purpose of this experiment was to study the effect of PRP on a mixture of autogenous bone and deproteinized bovine bone mineral (Bio-Oss) particles in goats. Four, round, critical size defects were made in the foreheads of 20 goats. In all goats the defects were filled with a mixture of autogenous particulate cancellous bone and (Bio-Oss) particles, in which 1 ml of PRP was added in two of the four defects. The goats were allocated to four subgroups each containing five goats, which were killed after 1, 2, 6 and 12 weeks. The results of the histological and histomorphometric examination showed that early and late bone healing were not enhanced when PRP was used.

The potential of the horizontal ramus of the mandible as a donor site for block and particular grafts in pre-implant surgery.

The results on 32 consecutive patients, who underwent bone grafting prior to implant surgery, are presented. The grafts were taken from the horizontal part of the mandible, including the full height of the buccal cortico-cancellous plate and were used to reconstruct alveolar defects or to augment sinus floors. 3-5 months postoperatively, 99 implants were inserted in 43 onlay grafts and in 17 sinus floor augmentations. The follow-up ranged from 2-6 years post implant insertion. Parameters examined included: healing of donor site and bone grafts, implant survival, peri-implant condition, donor site morbidity and patient satisfaction. This study indicates that with one full height ramus graft, alveolar defects comprising a bicuspid-molar area, can be augmented. The grafted volume is also sufficient to augment one sinus floor. The implant survival rate (99%) compares well with studies using iliac crest or skull bone. Postoperative complaints were minimal, resulting in extremely high patient satisfaction (97%).

[Complications and failures in dentoalveolar surgery]. / Complicaties en mislukkingen in de dentoalveolaire chirurgie.

Complications and failures are unavoidable in dentoalveolar surgery, but can be reduced if treatment is carried out in the proper manner. Yet, one has to accept a certain percentage of complications and failures and the patient should be informed about that prior to surgery. Complications become reproachable when insufficient diagnostic procedures have been carried out or when surgery has not been performed in the proper fashion. Insufficient prior information, even in cases of referral, must be seen as reproachable practice, especially in the context of the Law on Medical Treatment Agreement.

The effect of alar cinch sutures and V-Y closure on soft tissue dynamics after Le Fort I intrusion osteotomies.

UNLABELLED: Adverse effects on the soft tissues after Le Fort I osteotomies include: broadening of the alar base, loss of vermilion show of the upper lip and down sloping of the commissures. In theory, an alar cinch suture combined with a muco-musculo-periosteal V-Y closure (ACVY) should improve not only the nasal width, but would also improve the dynamics of some of the mimic muscles. To test the validity of this hypothesis, a prospective study was set up including 22 patients, using standardized full facial frontal photographs, taken immediately preoperatively and 18 months postoperatively. Sets containing three pictures were made: soft tissue in repose, maximum closed mouth smile and maximum smile. The landmarks, alare, crista philtri and cheilion were analysed. The preliminary results show that ACVY-closure does significantly improve the horizontal movement of cheilion with both maximum closed mouth smile and maximum smile, as well as the vertical movement of crista philtri with maximum closed mouth smile. CONCLUSION: The Le Fort I osteotomy with ACVY improves the orofacial dynamics.

The prediction of mandibular invasion by squamous cell carcinomas with the expression of osteoclast-related cytokines in biopsy specimens.

Destruction of bone by tumour is caused by osteoclasts rather than by tumour cells directly. Tumour cells of invasive oral squamous cell carcinomas (SCC) release osteoclast-related cytokines and cytokines activate osteoclasts. The purpose of this study was to investigate the possibility of predicting mandibular invasion by SCC by analysis of the expression of osteoclast-related cytokines in biopsy specimens of SCC, adjacent or fixed to the mandible. Thirty-five biopsy specimens from the pathology archives were examined from patients who had been treated for SCC, adjacent or fixed to the mandible. The patients were divided into those with and without medullary invasion. The expression of tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and IL-11 was studied by immunohistochemical analysis. No significant differences were found in expression of TNF-alpha, IL-6 and IL-11 between biopsy specimens with or without medullary invasion. Quantification of the density of tumour-infiltrating lymphocytes was not reproducible. In conclusion, the expression of TNF-alpha, IL-6 and IL-11 in biopsy specimens of SCC, adjacent or fixed to the mandible, is not an appropriate method for predicting the presence of medullary invasion of the mandible.

Modular endoprosthesis for mandibular body reconstruction: a clinical, micro-CT and histologic evaluation in eight Macaca fascicularis.

This paper presents the results of an animal experiment, in which a modular endoprosthesis is tested to replace a resected part of the mandible. The prostheses were fixed with polymethacrylate (PMMA) cement into the medullar space of the stumps. Clinical, radiologic, micro-computed tomographic and histologic evaluations were made after 3 and 6 months on four Macaca fascicularis for each implantation time. The prosthesis had not loosened but there were some loose screws that had caused fistulas in three animals. The stems of the modules were stably fixed with PMMA cement, surrounded by a fibrous capsule with inflammatory cells. This capsule was thinner in the 6-month group and showed less inflammatory infiltrate compared with the 3-month group; this was not statistically significant. There was an increase in woven bone surrounding the modules after 6 months. After 3 months of implantation, there was a considerable inflammatory reaction in the soft tissues surrounding the module, which subsided over following 3 months. The results are encouraging, but a longer period of follow-up is required to assess its application in a clinical setting, and some design drawbacks need to be addressed.

What is the quality of the evidence base for pre-implant surgery of the atrophic jaw?

This review aimed to evaluate the level of evidence for bone augmentation preimplant surgery for atrophic jaws in studies which measure outcome. Medline, Embase, Cochrane library and online journal searches were performed with a defined search strategy and the abstracts screened against selection criteria. The resultant papers were sorted by study design using the Cochrane study design algorithm, analysed for clinical/statistical homogeneity and graded with the Oxford Centre of Evidence-based Medicine levels of evidence. The initial online Medline search yielded 1194 results and the Embase search yielded 490 results. Using the selection criteria, 10 studies were identified. Additionally, 5 articles were identified from bibliography and online searches, giving a total of 15 studies for grading. All 15 studies were graded as level 4 evidence. No meta-analysis of outcomes was possible with the low level of evidence and degree of heterogeneity found. The best grade of recommendation that can be made for a particular preimplant surgical bone augmentation procedure, from these level 4 studies, is Grade C. Benchmarking studies by assessing quality of evidence can be helpful to inform future study designs with respect to reporting study outcomes with a higher level of evidence.