Lowering of the floor of the mouth: open or closed?

Trauner's (1952) open and Brown's (1953) closed method of lowering of the floor of the mouth are compared. Discomfort and other side effects were the same for both procedures, but Trauners method scores considerably better in the long term result.

Experimental and clinical results of new advances in the treatment of facial trauma.

Theoretical considerations and photoelastic and mechanical experiments showed us the progression from metal wires to metal plates in different systems. In the midface there is no question about stabilization by miniplate systems. For mandibular fracture treatment, there is a discussion going on at present about the use of stable maxisystems versus less stable minisystems. Our clinical experience of 15 years indicates that there is no further demand for strict stable fixation of mandibular fractures, and we were encouraged to use less stable systems with similar good results, as our follow-up and statistical evaluation showed. To continue the simplification of osteosynthesis methods we are performing experiments with resorbable materials. Early results show fracture healing comparable with that found with plate-and-screw systems. Our clinical experience has shown that there is no longer any question about the ability of stable fracture treatment by means of osteosynthesis. However, there still is the question of how functional such fracture treatment might be.

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.

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 grading of oral squamous carcinomas. A preliminary report.

The prognostic validity of the DNA-malignancy-grade (DNA-MG), ranging on a continuous scale from 0.00 to 3.00 was tested in a preliminary study on 7 patients with oral squamous cell carcinomas. Monolayer smears were prepared after a cell separation procedure from paraffin-embedded surgical tumor specimens. Feulgen staining was performed automatically in a modified Shandon staining machine. A TV image analysis system with an automatic microscope (TAS plus, Leitz, FRG) was used for DNA measurements. The DNA-MG revealed a strong correlation with the patients prognosis. 3 patients who died after having a tumor relapse (mean survival = 10 months) had DNA grades greater than 1.40, whereas patients who survived without having a tumor relapse (mean survival = 53 months) revealed DNA grades below 1.00. Additionally, the DNA-malignancy-grade was closely correlated with the histopathologic malignancy grades.

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%.

[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.

Augmentation with hydroxylapatite and vestibuloplasty in the atrophic maxilla with a flabby ridge.

Hydroxylapatite is used for maxillary ridge augmentation in combination with a submucous vestibuloplasty. Undermining and internal incision of the flabby ridge provides a tunnel for Hydroxylapatite insertion. After three weeks the augmented maxilla is stable enough for prosthetic treatment. Indications, technique and first year experience with 7 cases are described.

Visor osteotomy to increase the absolute height of the atrophied mandible. A preliminary report.

A method of operation is described whereby the alveolar ridge of the mandible is osteotomised and moved on the principle of a visor. The two parts are fixed together with wires, thus increasing the absolute height of the alveolar ridge of the mandible.

Follow-up investigation of surgical correction of the atrophic alveolar ridge by visor-osteotomy.

In 1975, a method of operation was described whereby the alveolar ridge of the mandible is osteotomied and moved on the visor principle. The two parts are fixed together with wires, thereby increasing the absolute height of the mandibular alveolar ridge. The visor-osteotomy in conjunction with vestibuloplasty and lowering of the floor of the mouth, significantly improves the denture bearing area, without the need for, and risk incurred by free bone transplantation. During the course of prosthetic treatment, one should bear in mind that there will be a temporary disturbance of sensation of the mucosa. Check-ups should be frequent. The post-operative results after three years were recorded in ten patients. There was 18% resorption of the augmented alveolar ridge over the first year. In the second year 10% and in the third year 8% or 0.6 mm. The same amount of mandibular resorption occurs following a simple, total vestibuloplasty. Three years after a visor mandibular ridge augmentation, the mandible shows physiological resorption.

[Harmonisation of the middle level of the face by Lefort type I osteotomy (author's transl)]. / Harmonisation de l'étage moyen de la face par ostectomie du type Lefort I.

Elongation of the middle level of the face which is characterised by a short upper lip and exposure of the superior alveolar process is an indication for resection of a boney segment of the maxilla. Planning of this operation and the surgical technique are described and it is shown that osteosynthesis using a miniplate makes it possible to avoid intermaxillary block but requires a strict surgical technique and a very careful therapeutic plan.

[Development of the facial and periodontal approach to the maxillary sinus]. / Die Entwicklung des fazialen und parodontalen Zugangs zur Kieferhöhle.

The nasal approach for operations of the maxillary sinus is becoming increasingly popular. The oral approach provides the best access for demonstration of the orbital floor, for ligation of the maxillary artery, for drainage of resistant rhinogenic sinusitis, and for removal of foreign bodies, tooth roots, dislocated teeth, odontogenic cysts and benign tumours of the maxillary sinus. Formerly the anterior wall of the maxillary sinus was removed, but nowadays procedures preserving the bone are chosen. The classical otorhinolaryngological incision lies in the limbus of the vestibule. Maxillofacial surgeons prefer an incision at the junction of the attached to the unattached gingiva because scars in the limbus of the vestibule create problems during later fitting of a denture. A follow-up of 40 patients shows that the gingival marginal incision causes no problems. This incision, introduced by Peter in 1930, is therefore preferred. The marginal incision does not leave any visible scars. It corresponds to an incision on the alveolar ridge in the edentulous patient.

[The position of the mandibular canal in the edentulous jaw]. / Die Lage des Mandibularkanals im zahnlosen Kiefer

The mandibular canal retains its position in the toothless lower jaw, irrespective of the degree of atrophy. The firm point of reference remains the distance from the mandibular border, the lingual and the buccal outer cortex. In the region of the first molar the distance from the mandibular border amounts on the average to 7.3 mm, 2.5 mm from the lingual aspect and 4.9 mm from the buccal. In the region of the lateral teeth the absolute height of the lower jaw is 0-31.6% lower than in the middle of the lower jaw (Average value 13.7%).

[Diagnosis of mandibular osteomyelitis]. / Diagnostik der Unterkieferosteomyelitis.

Eighty-four cases were compared clinically, radiologically, and scintigraphically with inflammatory changes in and around the mandible. A diagnostic schema was worked out for osteomyelitis of the mandible. According to our scintigraphic findings, the term osteomyelitis should include odontogenous purulence and periapical periodontitis.

[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.

Le Fort I ostectomy (using miniplates) for correction of the long face.

The increased middle face height, with a short upper lip and visible upper alveolar process, is an indication for removing a slice of bone from the maxilla. Planning of the operation and operative procedures will be described. It is shown that osteosynthesis with miniplates without the need for intermaxillary fixation is possible, provided that the planning is painstaking and that a precise operative technique is used.