Erik Hjørting-Hansen

Surgical treatment of premalignant lesions of the oral mucosa.

Abstract Oral premalignant lesions were treated by surgical excision in 61 patients. Criteria for inclusion in the study were epithelial dysplasia varying from slight to carcinoma in situ, or a non-dysplastic lesion located sublingually or on the tongue. The clinical diagnosis of the treated lesions were: erythroplakia 10, erythroleukoplakia 15, nodular leukoplakia 9, verrucous leukoplakia 9, homogeneous leukoplakia 13, and lichen planus 5. The surgically created defects were closed by direct approximation of the wound edges in 25 patients, transposition by a local mucosal flap in 9, covered with a free mucosal graft in 3, and by a free split skin transplant in 24 patients. The patients have been followed for an average period of 3.9 years after the operation. A recurrence rate of 20% was found, and 3 carcinomas developed in the follow-up period. The importance of using a surgical technique permitting histological examination of the entire lesion was documented by the finding of 4 superficial carcinomas in the excision specimen, undiagnosed in the preoperative biopsy.

Healing of experimentally created defects : a review

Within cranio-maxillofacial surgery and orthopedic surgery a bone graft or a bone substitute is required to recontour or assist bony healing in repair of osseous congenital deformities, or in repair of deformity due to trauma or to surgical excision after elimination of osseous disease processes exceeding a certain size. An autogenous bone graft is the optimal material of choice, however its use is problematic due to donor site morbidity, sparse amounts and uncontrolled resorption. Immunological responses and risk of viral contamination of allogenous and xenogenous bone materials make the use of these materials questionable. Healing and degradation of alloplastic materials are inconsistent with subsequent restricted use. The principle of guided tissue regeneration excluding soft tissue cells from a certain area is not alone sufficient to insure complete bony healing. Recombinant bone morphogenetic proteins have with success been added as adjuncts to already known biomaterials. In the future, inductive materials together with a suitable carrier and a biodegradable membrane may be the choice of bone substitute used within cranio-maxillofacial and orthopaedic surgery.

Evaluation of Guided Bone Generation Around Implants Placed Into Fresh Extraction Sockets: An Experimental Study in Dogs

Immediate placement of implants into fresh extraction sockets would have the principal advantage of decreasing the recommended period of healing. It also would result in a guided placement of the implant, and it could reduce the resorption of the alveolar bone in the extraction area. However, when an implant is placed immediately into an extraction socket, it may not engage the walls of the socket near the crest of the alveolar ridge. With the presence of a bone defect around an implant, ingrowth of soft tissue could compromise the achievement of osseointegration in the crestal bone area. The objective of this study was to evaluate the crestal bone healing response adjacent to implants placed immediately into fresh extraction sockets with and without covering membranes. Eight adult mongrel dogs had the third and fourth mandibular premolars extracted bilaterally. Thirty-two submerged titanium hollow-screw implants were inserted immediately into the extraction sockets. On the right side, the implants were covered with an expanded polytetrafluorethylene membrane, whereas the left side served as a control. One dog was killed after 2 weeks, one after 4 weeks, and six after 12 weeks. Soft tissue dehiscence developed over 10 implants (12-week dogs) covered with membranes. Dehiscence was noted histologically over three contralateral control implants. When soft tissue dehiscence occurred and the membrane was left exposed without oral hygiene during healing, the degree of bone integration was significantly less than in the control sites without membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Recurrence of the odontogenic keratocyst in 13 patients with the nevoid basal cell carcinoma syndrome: A 6-year follow-up

A 6-year follow-up study of 44 primarily enucleated odontogenic keratocysts from 13 patients with the characteristics signs and symptoms of the nevoid basal cell carcinoma syndrome (NBS) is presented. The 2-, 3-, 4-, 5- and 6-year follow-ups revealed an incidence of recurrence by the single keratocyst of 20, 30, 39, 50 and 55%, respectively. These figures demonstrate that the majority of the recurrences occurred within a period of 5 years postoperatively. However, as the proportion of increased recurrence in the period from 5 to 6 years postoperatively was 5%, a follow-up period of more than 6 years is necessary in order to make the diagnosis of recurrence without any delay in all patients with NBS. The occurrence of odontogenic epithelium and/or microcysts in the cyst wall of keratocysts without any recurrence at the 5-year follow-up was compared with the occurrence of similar histopathologic features in keratocysts which at the 5-year follow-up had shown recurrence. The occurrence of odontogenic epithelium and/or microcysts was demonstrated in 43% of the group of keratocysts without recurrence and in 57% of the group of keratocysts with recurrence. However, this difference is not statistically significant (P > 0.10) and indicates that the high occurrence (50%) of odontogenic epithelium and/or microcysts in NBS-keratocysts is not significantly correlated to the recurrence.

Changes in bone mass in rat mandibles after tooth extraction

An experimental study concerning changes in bone mass in trabecular bone of mandibles on rats after extractions of upper molars has been carried out. The material consisted of 32 SPF Wistar rats, fed on Nafag-184 only. Experimental and control groups consisted of eight females and eight males, each group having same average weight with respect to sex at the age of 16 weeks. At this age the upper right molars were extracted on all rats in the experimental group. The rats were sacrificed after 16 weeks. Identical increase in weight within each sex group was found. Microradiograms of two buccal-lingual 100-mu-thick ground sections at a distance of 0.5 mm through the first molar in each side of the mandible were used. Quantitation of bone mass (bone area in percent) of a trabecular bone was done by electronic point counting. No significant difference in bone mass was found between left and right sides in the control group (P greater than 0.50), whereas a significant difference was found between left and right sides in the experimental group (P approximately 0.0001) with lowest mean value in right sides. Conclusively the analysis shows that local reduction in bite force causes osteoporotic changes in trabecular bone of the jaw.

Benign cementoblastoma: A review and five new cases

This article includes five new cases of benign cementoblastoma. The study includes a review on 66 previously published cases that we consider to be bonafide cases. It is considered that benign cementoblastoma continues to be an infrequent entity that particularly affects young patients under the age of 30. The sex distribution shows a slight tendency for being more common in females. The most frequently effected area is the mandibular molar-premolar region. Pain, expansion and, radiographic radiopacity surrounded by a peripheral radiolucent halo are the most striking features. Treatment and prognosis are also discussed. Histopathologic conditions and factors to be considered with respect to differential diagnosis conclude the report.

The mandibular bone mineral content in relation to vestibulolingual sulcoplasty. A 2-year follow-up

The bone mineral content (BMC) in mandibles can now be measured in vivo with high precision by a specially constructed dual-photon scanner. This study analyzed, over a 2-year period, the BMC loss of endentulous mandibles in a group of young and older women after vestibulolingual sulcoplasty with free skin grafts, and its relationship to the initial mandibular BMC and the age-related mandibular BMC loss. BMC in the denture-wearing site and the standard site of the mandible was measured by this method. A significant negative relationship was found between the initial BMC values in the standard site and the BMC loss (in percent) in the denture-wearing site in both age groups, and a significant positive relationship between the BMC loss (in percent) in the two sites of the mandible in the elder group. The rate of residual ridge reduction may be predicted from the initial mandibular BMC value and seems to be dependent on the age-related mandibular BMC loss.

Bone grafting to the jaws with special reference to reconstructive preprosthetic surgery

The first report on the transfer of fresh bone was in 1668 when van Meekeren described how a Russian surgeon had repaired a soldier’s skull defect by implanting dog bone with good results. Discovery of the anesthetics, nitrous oxide and ether, in addition to the introduction of antisepsis opened up new surgical possibilities and made bone grafting a possible clinical procedure. Around the turn of the last century, papers began to appear on the restoration of continuity defects of the mandibula. In the future it will be possible to acquire a living graft in the exact size desired based on a 3D reconstruction of a CT scan of the defect. Der erste Bericht über einen Transfer von frischem Knochen wurde 1668 von van Meekeren gegeben. Er beschrieb, dass ein russischer Chirurg den Schädeldefekt eines Soldaten durch Implantation von Hundeknochen wiederherstellte und gute Ergebnisse erzielte. Die Entdeckung von Anästhetika, Nitritoxid und Äther zusammen mit der Einführung der Antisepsis eröffneten neue chirurgische Möglichkeiten, insbesondere auch die der Knochentransplantation. Ungefähr um die Jahrhundertwende erschienen erste Veröffentlichungen über die Wiederherstellung von Kontinuitätsdefekten der Mandibula. In Zukunft wird es möglich sein, lebenden Knochen in exakt der gewünschten Größe, basierend auf einer 3D-Computerrekonstruktion des Defekts, einzusetzen.

BONE RESORPTION AFTER ADVANCEMENT GENIOPLASTY : PEDICLED AND NON-PEDICLED GRAFTS

The influence of soft tissue attachment in augmentation genioplasty on the amount of postoperative bone remodelling was studied in 29 patients. The soft tissue was completely detached from the advanced genial segment in 15 patients and the lingual soft tissue was maintained in 14 patients. The advancement of the chin and postoperative bone remodelling was analysed by measuring linear distances and areas on lateral cephalograms. The genial segments with a soft tissue pedicle underwent significantly less resorption than the free grafts (p less than 0.01). The difference in postoperative infection between the two groups (p less than 0.05) indicates that the likelihood of postoperative infection is significantly reduced by maintaining the soft tissue pedicle. Considerably less variation in amount of bone resorption was also observed in the patients with a pedicled graft.

The pattern of postoperative bone resorption following mandibular vestibulolingual sulcoplasty with free skin graft

The results of a cephalometric analysis of 70 patients in whom a mandibular vestibulolingual sulcoplasty with free skin graft was done are presented. The subjects were 56 women and 14 men who had worn dentures for an average of 17 years and had been followed up for as long as five years after the operation. The analysis showed an average of 1.7 mm loss of anterior height in the symphysis region in the first year after operation. After that time, no further increase in bone loss was observed. There was a tendency for greater resorption in patients with a small gonial angle. No correlation was found between the degree of resorption and sex, age, beta angle, and symphysis angle. There was a strong correlation between the loss in anterior height of the symphysis region and the loss of area in square millimeters.