[Calcification of the falx cerebri. A pathognomonic symptom of Gorlin-Goltz syndrome]. / Verkalkung der Falx cerebri. Ein pathognomonisches Zeichen beim Gorlin-Goltz-Syndrom.

BACKGROUND: Gorlin-Goltz syndrome is an autosomal dominant disorder with variable penetration characterized primarily by keratocysts of the jaws, multiple basal cell carcinomas, skeletal abnormalities and intracranial calcifications. METHOD: In this study, 4787 radiographs with occipitomental x-rays from the hospital archives for oral and maxillofacial surgery of the Christian Albrechts University Kiel were examined for calcifications in the area of the falx cerebri. RESULTS: Four characteristic alterations in the falx cerebri could be assigned to four groups of structures. Those in group 4 could be found only within Gorlin-Goltz syndrome patients, and differed significantly in form and extent from the remaining three groups. CONCLUSION: The plurilamellar appearance of this group could be rated as a pathognomonic symptom of the Gorlin-Goltz syndrome.

[Comparison of secondary and tertiary cleft jaw osteoplasty. 20 year analysis]. / Vergleich der sekundären und tertiären Kieferspaltosteoplastik. Analyse über 20 Jahre.

BACKGROUND: The aim of secondary cleft osteoplasty is to provide alveolar bone for the complete eruption of the canine and sometimes of the lateral incisor to the occlusal plane and, thus, preservation of a continuous dental arch. This concept has not changed during the last 20 years in our clinic, providing an opportunity for an analysis of a homogeneous group of cleft patients. This group of patients was compared with a similar group of tertiary osteoplasties, performed during the same time span in our clinic. MATERIAL AND METHODS: From 1980 to 1999, 376 cleft osteoplasties were performed in 295 patients, 264 of whom (136 secondary and 128 tertiary osteoplasties) were available for continuous prospective follow-up. Special emphasis was put on preoperative orthodontic treatment with removal of crossbites, oral hygiene, and meticulous disinfection. Autogenous cancellous iliac bone was used exclusively. RESULTS: The postoperative height of the interalveolar septum (Abyholm classes) was I (1/1, 69.4%/45.8%), II (> 3/4, 28.2%/41.7%), III (< 3/4, 2.4%/10%), and IV (complete failure, 0%/2.5%) (secondary vs tertiary). Complications were infections (6.6% vs 14%), fistulae (0.7% vs 5.8%), and external root resorption (0% vs 7.4%). The lateral incisor was aligned into the arch in 55.5% vs 29.8% and the canine was in the correct position in 100% vs 83.6% (secondary vs tertiary). CONCLUSION: Secondary cleft osteoplasty was more advantageous than tertiary due to better preservation of the neighboring teeth.

[Precancer stages of the oral mucosa: a review]. / Die Krebsvorstufen der Mundschleimhaut--eine Ubersicht.

UNLABELLED: According to the WHO collaborating centre precancerous lesions and precancerous conditions have to be distinguished. Precancer: BACKGROUND: Erythroplakia is the most dangerous precancerous lesion. It is rare, but may often remain undetected. It will transform into cancer within five years and therefore, has to be excised in every case. Leukoplakias show malignant transformation in 3-45% of the cases. In spite of modern molecular biological and immunohistochemical techniques the clinical appearance and the histological grading of the dysplasia are still most important prognostic factors. Until 1992 every lesion showing signs of moderate and severe dysplasia was excised in our department. Despite this treatment strategy 6.2% of the leukoplakias (n = 161) transformed into cancer. Therefore, we recommend to remove every lesion which does not disappear after eliminating the etiological factors. METHODS: Since 1992 168 leukoplakias were completely removed using the CO2 Laser and underwent histological examination. RESULTS: In 3% of these cases a carcinoma was detected in the leukoplakia; 5% of the lesions recurred. Precancerous condition: The most important precancerous condition, the oral lichen planus is treated in cases of erosive lesions only or if the patient is suffering from the symptoms. Malignant transformation is seen in 1.5% of the patients within 10 to 15 years. Histologically the oral lichen planus does not differ from the oral lichenoid reactions, lesions in contact with amalgam restorations mostly. In these cases a causative treatment with replacement of the amalgam is recommended.

[Preprosthetic surgery (without implantology)]. / Präprothetische Chirurgie (ohne Implantologie).

This paper describes preprosthetic surgery from its historical beginnings to its present state-of-the-art status. Future perspectives of preprosthetic surgery are also outlined, excluding implants. In an enquiry of 250 German-speaking maxillofacial departments, 160 responded. Results showed that a surprising 30-50% of the institutions are still following guidelines for procedures which have been proven by scientific follow-up studies to be almost 100% unsuccessful.

The self adapting washer for lag screw fixation of mandibular fractures: finite element analysis and preclinical evaluation.

Besides rigid fixation, lag screws have distinct advantages compared with plates in appropriate indications in mandibular fractures. However, in current lag screw systems, the relatively small area of the screw head has to transfer the tensile force which can exceed 1000 N in the symphysis, to the thin cortical bone plate. Countersinking, which is obligatory in most systems, will weaken the cortical plate. Finite element analysis (FEA) revealed that load in this situation can exceed the normal tensile strength of metal and bone. Consequently, a new washer was constructed which both increased the supporting surface and did not require countersinking. The washer is self adapting (SAW) to the cortical plate in a defined position, forming a ball and socket joint with the screw head. Using the FEA model, a ten-fold reduction in load on bone and metal was observed with the new washer. In a miniature pig mandibular symphysis fracture model, the clinical applicability and a favourable histological reaction were demonstrated, compared with conventional lag screw designs.

Self-adapting washer system for lag screw fixation of mandibular fractures. Part II: In vitro mechanical characterization of 2.3 and 2.7 mm lag screw prototypes and in vivo removal torque after healing.

The aim of this study was to mechanically characterize self-tapping 2.3 and 2.7 mm titanium lag screw prototypes which are part of the newly developed 'self-adapting washer' maxillofacial lag screw osteosynthesis system. In vitro in a screw testing machine the insertion torque, maximum locking torque and axial force and the ultimate torsional strength were assessed. In vivo in six miniature pigs using a mandibular symphyseal fracture model, the removal torques after 3 and 6 months of healing were measured. Additionally the bone-metal contact (BMC) of the screws was assessed histometrically. The maximum insertion torque (0.185 Nm) was far below the mechanical limits of the screws (2.3 mm = 0.96 Nm, 2.7 mm = 1.6 Nm). A tightening of the 2.7 mm screw with an axial force of 1000 N and of the 2.3 mm screw with 500-550 N leaves a safety margin of approximately one-third on the ultimate torsional strength. Clinically these values permit the use of two 2.3 mm lag screws or one 2.7 mm lag screw in mandibular symphysis fractures since 1000 N tensile axial force are required in this indication. During screw removal after 6 months healing, torque levels close to the mechanical limits of the screws were recorded and screw failures were observed. This failure rate may have been due to the BMC of 49.8% which was in the range of titanium dental implants. Accordingly the screw heads were reinforced to prevent fractures.

Preoperative radiochemotherapy and radical surgery in comparison with radical surgery alone. A prospective, multicentric, randomized DOSAK study of advanced squamous cell carcinoma of the oral cavity and the oropharynx (a 3-year follow-up).

A multicentric, randomized study of squamous cell carcinoma (SCC) of the oral cavity and the oropharynx has been undertaken by DOSAK. The results after radical surgery alone have been compared with the results of combined preoperative radiochemotherapy followed by radical surgery. Patients with primary (biopsy proven) SCC of the oral cavity or the oropharynx with tumor nodes metastasis (TNM) stages T2-4, N0-3, M0 were included in the study. A total of 141 patients were treated by radical surgery alone, whereas 127 patients were treated by radical surgery preceded by preoperative radiochemotherapy. The preoperative treatment consisted of conventionally fractioned irradiation on the primary and the regional lymph nodes with a total dose of 36 Gy (5 x 2 Gy per week) and low-dose cisplatin chemotherapy with 5 x 12.5 mg cisplatin per m2 of body surface during the first week of treatment. Radical surgery according to the DOSAK definitions (DOSAK, 1982) was performed after a delay of 10-14 days. During the follow-up period, 28.2% of all patients suffered from locoregional recurrence, and 27.2% of the patients died. The percentages were higher after radical surgery alone for locoregional recurrence (31% and 15.6%) and for death (28% and 18.6%). The life-table analysis showed improved survival rates of 4.5% after 1 year and 8.3% after 2 years in the group of patients treated with combined therapy. The demonstrated improvement appeared to be significant with the Gehan-Wilcoxon test as well as with the log rank test below a P value of 5%.

[Active canine tooth movement by spongiosa graft in bilateral cheilognathopalatoschisis]. / Aktive Eckzahnbewegung durch das Spongiosatransplantat bei einer doppelseitigen Lippen-Kiefer-Gaumen-Spalte.

Bone grafting in the alveolar cleft offers a bony support in the alveolar process for the erupting canines and should be performed before the eruption of the teeth starts. Although bone grafting is done in time, the eruption of the canines does not always follow spontaneously. This is why a simultaneous ligation of the canines is sometimes indicated. The ligature can be threaded through the bone graft. Active eruption of the canines can begin eight weeks post operation. This procedure ensures a proper alignment of the canines in a well-defined processus alveolaris. The method is demonstrated in a bilateral cleft lip and palate patient.

Augmentation of the alveolar ridges with hydroxylapatite in a Vicryl tube.

The technique discussed describes the use of a Vicryl tube for maintaining hydroxylapatite (HA) granules in their correct position when augmenting the atrophic maxillary or mandibular alveolar ridge. The method involves simultaneous submucous vestibuloplasty in both the maxilla and the mandible and is also combined with lowering of the floor of the mouth. 118 patients (73 women and 45 men) were treated by this method. The results of augmentation in 64 maxillary and 54 mandibular cases are presented.

DNA-cytometric detection of euploid polyploidization in oral lichen ruber planus.

The DNA distribution was analyzed in 29 cases of oral lichen ruber planus that were negative for human papillomavirus and not suspected of being precancerous. Monolayer smears prepared from formalin-fixed, paraffin-embedded tissues were automatically Feulgen stained and used for rapid interactive DNA cytometry via a TV-based image analysis system combined with an automated microscope. Nuclei with DNA contents greater than 4c were found in 25 cases (86%). DNA contents greater than 8c were seen in five cases (17%), and small peaks at 8c were found in three cases. These increased DNA values in nonprecancerous lesions must be interpreted as euploid polyploidization and have to be taken into account if DNA measurements are performed for diagnostic purposes in lichen ruber planus lesions that are suspected of having malignant transformation.

[Preoperative radio-chemotherapy and radical surgery for advanced carcinomas of the oral cavity. 4-year results of a prospective therapy study with DOSAK]. / Präoperative Radio-Chemotherapie und radikale Operation fortgeschrittener Mundhöhlenkarzinome. 4Jahresergebnisse einer prospektiven Therapiestudie des DOSAK.

Based on the postoperative data evaluated in September 1989, the results of a regional prospective treatment study conducted by the DOSAK on preoperative radio-chemotherapy and radical surgery for carcinomas of the oral cavity and the oropharynx are presented. In the univariate analysis the histologic lymph node findings after pretreatment, the histologic grading, and the TPI correlated well with the survival rates. The multivariate analysis confirmed that the histologic demonstration of vital tumor cells in the neck lymph nodes after the end of pretreatment is of grat prognostic relevance. The histologic degree of differentiation, the demonstration of vital tumor cells in the primary tumor area after pretreatment and the length of time between radiotherapy and surgery were of secondary importance.