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.

Healing of bone defects in the goat mandible, using COLLOSS E and beta-tricalciumphosphate.

COLLOSS E, an equine extracellular matrix product containing native transforming growth factor beta1 and several bone morphogenetic proteins, has shown osteoinductive properties in ectopic sites. This study was set up to examine its properties in an orthotoptic site in conjunction with a beta-tricalciumphosphate (beta-TCP) scaffolding material. Thirty-two 17-mm circular defects in goat mandibles were filled with COLLOSS E, beta-TCP, COLLOSS E + beta-TCP, or left empty. After 9 weeks the results were quantified by micro-computed tomography and histology. The empty defects contained the highest percentage of new bone (62%). The beta-TCP scaffold resulted in 38% (p = 0.0029), the mixture of beta-TCP/COLLOSS E resulted in 36% (p = 0.0057), while the use of COLLOSS E alone resulted in 55% (not significant p = 0.34). These results show that addition of TCP did not result in the expected synergy with regard to the healing of the defect and seemed even to inhibit the healing process. On the other hand, the addition of COLLOSS E induced the formation of small islands of new bone, not connected to the defect edges. This was not observed in the specimens not containing COLLOSS E (4.61% of bone formation centrally in the defect vs. 0.56%; p = 0.042). In conclusion, the results of the present study are somewhat unexpected in that the empty defects showed the most bone ingrowth; however, this ingrowth was always connected to the defect edges. In contrast, the application of COLLOSS E with or without beta-TCP induced bone formation in the center of the defects also.

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.

Peri-implant and systemic release of metallic elements following insertion of a mandibular modular endoprosthesis in Macaca fascicularis.

The aim of this study was to assess the release of metal elements from a Ti6Al4V modular endoprosthesis for mandibular reconstruction. Ten monkeys were included, seven of the animals had an endoprosthesis inserted and three served as controls. Mucosa, regional lymph nodes and distant organs, were assessed after the implant had been in place for 12 months, using light (LM) and transmission electron microscopy (TEM) and inductively coupled plasma optical emission spectroscopy (ICP). Blood was also drawn from all animals for elemental analysis using ICP. LM and TEM evaluation showed no detectable metal particles in the mucosa surrounding the endoprosthesis, nor in the regional lymph nodes and distant organs. Blood analysis revealed that titanium and vanadium were detectable in comparable amounts in the test (Ti: 1.63+/-0.54, Va: 0.42+/-0.08) as well as in the control group (Ti: 2.07+/-0.55, Va: 0.37+/-0.07). The amount of aluminum appeared to be higher in the control group (31.77+/-11.67) compared with the test group (20.41+/-9.13), but this difference was not statistically significant. ICP showed that no titanium, vanadium or aluminum was detectable in the mucosa surrounding the endoprosthesis. In addition, no titanium and vanadium were found in the lymph nodes and distant organs using ICP. On the other hand, using ICP, the aluminum content was found to be higher in the right regional lymph nodes and all examined distant organs as compared to the control group (lymph nodes: 11.55+/-22.15 vs. 0.36+/-0.61, lung: 6.24+/-11.28 vs. 1.40+/-2.15, liver: 1.66+/-0.99 vs. 0, kidney: 15.69+/-24.88 vs 0, spleen: 2.75+/-3.09 vs. 0.49+/-0.43). However, only for the kidney and liver the higher amount of aluminum was statistically significant. In conclusion, this study quantified the release of only aluminum in lymph nodes and distant organs, when using a modular endoprosthesis made of Ti-6Al-4V for mandibular reconstruction.

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.

Analytical assessment of the osteoinductive material COLLOSSE.

In this study, the growth factors in COLLOSSE were analyzed, using ELISA tests, mass spectrometry, western blotting, and a 24-day cell culture experiment using osteoblast-like cells. The results of the ELISA testing, mass spectrometry, and western blotting all confirmed that TGF-beta1 was the main growth factor in COLLOSSE at 55 ng/mg. The results from the culture test showed that the cell proliferation, alkaline phosphatase activity, and matrix calcification were all drastically changed by the addition of COLLOSSE, mirroring the effects of addition of TGF-beta1. We conclude that COLLOSSE is not only a rich source of TGFbeta-1, but also contains the growth factors TGFbeta-2, BMP-2, BMP-3, BMP-7, IGF-1, and possibly VEGF. Other growth factors might be present in COLLOSSE, but were not identified due to inherent detection limits of the used ELISA and mass spectrometry techniques. The number of osteoinductive factors in COLLOSSE causes a synergistic effect, explaining the new bone formation found in previously described in vivo studies, with much lower growth factor concentrations when compared with recombinant BMPs.