Paul J.W. Stoelinga

Excision of the overlying, attached mucosa, in conjunction with cyst enucleation and treatment of the bony defect with carnoy solution

Odontogenic keratocysts (OKCs) are known for which overlooked an important aspect of the detheir tendency to recur. The reported recurrence rates vary from approximately 20% to 60% [1–14]. The interpretation of these studies, however, is seriously flawed by different follow-up periods, whereas different modes of treatment have been used and the number of patients involved are often small. Blanas et al [2] reviewed the literature using four criteria for incorporation in their evaluation: (1) adequate diagnostic evaluation, (2) adequate description of patient selection process, (3) adequate description of the follow-up period, (4) adequate description of the treatment. Only nine papers unequivocally met these criteria, whereas six were added after discussion within the group of examiners, which brought the total to 15. In their report, the total number of patients in the various studies ranged from 1 to 72, with considerable variation in follow-up periods ranging from 2 months to 21 years. They concluded that resections are associated with low recurrence rates, but the numbers involved were small, except for one study in which 31 patients were involved. Enucleation or curettage and marsupialization gave rise to the highest recurrence rates. They did not specify the technique as described by Stoelinga and Peters [15], Voorsmit et al [16], and Stoelinga and Bronkhorst [17] in that no mention was made of the importance to excise the overlying attached mucosa. They simply mentioned that enucleation and Carnoy’s resulted in a low incidence of recurrences,

The role of the intraosseous osteosynthesis wire in sagittal split osteotomies for mandibular advancement

Two groups of 20 patients who were treated for mandibular hypoplasia by surgical lengthening of the mandible using the bilateral sagittal split ramus osteotomy were followed pre- and postoperatively using serial lateral cephalograms. One group of patients was treated without internal fixation and the second group, with superior border intraosseous osteosynthesis wiring. Both groups were evaluated for postoperative skeletal and occlusal changes and the results were compared. A notably greater amount of relapse was observed in the group of patients in whom no intraosseous wiring was used.

Replacement of the Condyle and Ascending Ramus by a Modular Endoprosthesis in Macaca fascicularis— Part 1: A Clinical and Radiographic Study

PURPOSEnTo evaluate the feasibility of replacing the condyle and ascending ramus with a novel modular endoprosthesis in Macaca fascicularis.nnnMATERIALS AND METHODSnEight male adult monkeys (Macaca fascicularis) were used in this study. The right condyle and ascending ramus posterior to the lower second molar were resected. An endoprosthesis consisting of 2 modules was inserted to replace the resected segment and fixed in place using polymethylmethacrylate bone cement (Palacos). Four monkeys were sacrificed at 3 months and another 4 at 6 months postoperatively. The operated side of the mandible was then harvested, including the endoprosthesis and the stump of the mandible to which it was attached. Lateral mandibular radiographs were taken using standard settings immediately postoperatively and postsacrifice.nnnRESULTSnTwo monkeys presented with a fistula at the operated area 1 month postoperatively, but this resolved with a short course of antimicrobial treatment. At the time of sacrifice, no fistulas, dehiscences, or mobility of the endoprostheses was observed. There was no significant change in maximum mouth opening. At 3 months, a linear radiolucency was noted at the cement-bone interface in the 2 monkeys that previously presented with fistulas; whereas at 6 months, none of the 4 animals showed any radiolucency.nnnCONCLUSIONSnThe use of a cemented modular endoprosthesis for replacement of the condyle and ramus unit was feasible with minimal complications allowing normal mouth opening and occlusion. Further histologic and microfocus computed tomographic studies will be done to confirm the findings.

Assessment of bone vascularity in the anterior mandible using laser Doppler flowmetry.

OBJECTIVESnIn irradiated bone, a method assessing vascularity of intended implant recipient bone would be of clinical significance in preventing early implant loss and in reducing the risk of osteoradionecrosis due to surgical oral implant insertion. At present, assessing bone vascularity clinically, using laser Doppler flowmetry (LDF), seems to be realistic. The hypotheses of this study were that bone vascularity in the human anterior mandible can be assessed during implant insertion by LDF and that the recorded LDF values are providing standard data for bone vascularity in the human anterior mandible.nnnMATERIAL AND METHODSnTwenty-three randomly selected non-irradiated edentulous patients scheduled for treatment with oral implants in the anterior mandible were assigned, 12 men and 11 women. The patients history of edentulousness and resorption of the residual alveolar ridges were registered. In pilot osteotomy sites of planned implant insertion, the bone vascularity was registered, using LDF and expressed in perfusion units (PU). The statistical distribution and characteristics of the LDF values were explored, separately for men and women.nnnRESULTSnA total of 41 pilot osteotomy sites were recorded with a mean LDF value of 25.80 PU. No obvious gender difference was found and LDF values did not show a relationship with patients age or history of edentulousness.nnnCONCLUSIONnThe hypotheses that bone vascularity in the human anterior mandible can be assessed during implant insertion by LDF and that the recorded LDF values are providing standard data for bone vascularity in the human anterior mandible, were confirmed.

The Management of Aggressive Cysts of the Jaws

There are essentially six types of aggressive cysts of the jaws that require special attention, so as to avoid recurrence, or even worse, widespread disease. They include, botryoid cysts, cysts in which carcinoma’s arise, glandular odontogenic cysts, calcifying cystic odontogenic tumour, previously called calcifying odontogenic cyst and unicystic ameloblastoma and keratocystic odontogenic tumor, previously called odontogenic keratocysts. The estimated incidence of these cysts, based on some review studies has been discussed. The main issue, however, when treating a cyst of the jaws is; how sure can one be that the lesion is benign or potentially aggressive? In order to answer this question it is important to know how these cysts commonly present. The clinical presentation, frequency of occurrence and suggested modes of treatment has been addressed.

Intensity-modulated radiation therapy for oropharyngeal cancer: Radiation dosage constraint at the anterior mandible

Because the survival of endosseous implants in irradiated bone is lower than in non-irradiated bone, particularly if the irradiation dose exceeds 50Gy, a study was carried out to assess the irradiation dose in the anterior mandible, when intensity modulated radiation therapy (IMRT) is used. The hypothesis was that adequate IMRT planning in oropharyngeal cancer patients is allowing sufficiently low anterior mandibular bone radiation dosages to safely insert endosseous implants. Ten randomly selected patients with oropharyngeal cancer, primarily treated by intensity-modulated radiotherapy (IMRT), were included in this study. First, at five determined positions distributed over the anterior mandible, the appropriate radiation dosages were calculated according to the originally arranged fractionated radiation schedule. Second, for each patient an adjusted fractionated radiation schedule was established with an extra dose constraint which allowed a lower dose in the mandible taking into account that the anterior mandible needs protection against radiation-induced osteoradionecrosis. The goal for the adjusted fractionated radiation schedule was similar as that of the original fractionated radiation schedule, including a desired tumour target dosage of 70Gy and maximum mean local dosages for organs at risk. The data revealed a considerable and statistically significant, irradiation dose reduction in the anterior mandible without compromising the other constraints. As a result of this study it is strongly advised to maximize dose constraint to the anterior mandible when planning irradiation for oropharyngeal cancer patients, using IMRT. This would greatly facilitate successful implant treatment for this group of patients. The fractionated radiation schedules used, should also be used for the planning of the best implant positions by integrating them in the implant planning software.

Reappraisal of the mandibular step osteotomy.

The intraoral step osteotomy of the mandibular body may have wide application in the treatment of dentofacial deformities. The existing literature is reviewed, cases illustrating the applications of the step osteotomy are presented, and the results of a retrospective clinical study of 47 patients are reported.

Soft tissue adaptation to modified titanium surfaces

Surface modification of titanium alloy implants to enhance soft tissue adherence is important to minimize soft tissue dehiscence. This study aimed to confirm if a dual acid etched Osseotite® titanium surface contributes to soft tissue adherence in muscle. It also aims to explore if a radio frequency magnetron sputtered hydroxyapatite (HA)/bioglass (BG) coating can serve this purpose and provides soft tissue adherence in mucosal tissue. The study was carried out in 18 Macaca fascicularis animals, 14 Osseotite® coated Ti6Al4V bullets inserted intramuscularly and 12 HA/BG coated Ti6Al4V plates inserted into the submucosa. These were compared with machined Ti6Al4V surfaces as controls. The histological and histomorphometrical results revealed that no significant difference existed in muscle tissue response between machined and Osseotite® surfaces. On the other hand, the HA/BG coated submucosal plates showed statistically significant differences with a thinner capsule quantity (p < 0.0001), an increased capsule quality (p < 0.0001) and interface quality score (p < 0.05). In conclusion, the deposited HA/BG coatings facilitated soft tissue (mucosa) adaptation at 1 month of implant installation, whereas the acid etched Osseotite® surface did not enhance muscular adaptation.

Replacement of the condyle and ascending ramus by a modular endoprosthesis in Macaca fascicularis--part 4: evaluation of the temporomandibular joints.

PURPOSEnTo assess, using cone-beam computed tomography and histologic examination, whether the fixation of a condyle-ascending ramus mandibular modular endoprosthesis results in a physiologic condylar replacement in Macaca fascicularis.nnnMATERIALS AND METHODSnThe right condyle and ascending ramus were resected in 8 adult monkeys and replaced with a modular endoprosthesis, fixed with polymethyl methacrylate bone cement (Palacos). Four monkeys were sacrificed at 3 months and another 4 at 6 months postoperatively. The reconstructed and contralateral temporomandibular joints were harvested en bloc and studied using cone-beam computed tomography and descriptive histologic examination. Heterotopic bone formation was quantified using a modified grading scale. The condyle cartilage thickness in the contralateral temporomandibular joint was measured using histomorphometric methods. The results were compared with those of the unoperated control monkeys.nnnRESULTSnBone resorption in the glenoid fossa and pathologic changes in the articular disc were noted on the reconstructed side in most specimens. Nevertheless, cone-beam computed tomography findings, histologic findings, and condyle cartilage thickness measurements of the contralateral temporomandibular joint were not significantly different from those of the control specimens.nnnCONCLUSIONnReplacement of the condyle and ascending ramus using a modular endoprosthesis in Macaca fascicularis resulted in adaptive remodeling of the glenoid fossa at up to 6 months postoperatively. Long-term studies are required to further assess the potential of this mode of reconstruction.

Replacement of the condyle and ascending ramus by a modular endoprosthesis in Macaca fascicularis--part 3: evaluation of peri-implant bone remodeling.

PURPOSEnTo assess whether the fixation of a condyle-ascending ramus mandibular modular endoprosthesis, using bone cement, will result in stress-related bone resorption in the Macaca fascicularis.nnnMATERIALS AND METHODSnThe right condyle and ascending ramus were resected in 8 adult monkeys and replaced by a modular endoprosthesis, fixed with polymethylmethacrylate bone cement (Palacos). Four monkeys were sacrificed at 3 months and another 4 at 6 months postoperatively. The bone mineral density was assessed using dual-energy x-ray absorptiometry in the region anterior to the stem and using micro-computed tomography in the buccal, lingual, and inferior regions adjacent to the stem.nnnRESULTSnThe bone mineral density of the 3-month specimens was greater than that at 6 months in the buccal, lingual, and inferior regions adjacent to the stem. However, the difference was statistically significant only in the inferior aspect. No significant difference was found in the bone mineral density in the region anterior to the stem between the 3- and 6-month specimens.nnnCONCLUSIONnA minimal reduction in bone density around the stem of the endoprosthesis was observed between 3 and 6 months after placement. This reduction did not result in any adverse clinical events.