Klaus Louis Gerlach

Mutations of the ephrin-B1 gene cause craniofrontonasal syndrome.

Craniofrontonasal syndrome (CFNS) is an X-linked craniofacial disorder with an unusual manifestation pattern, in which affected females show multiple skeletal malformations, whereas the genetic defect causes no or only mild abnormalities in male carriers. Recently, we have mapped a gene for CFNS in the pericentromeric region of the X chromosome that contains the EFNB1 gene, which encodes the ephrin-B1 ligand for Eph receptors. Since Efnb1 mutant mice display a spectrum of malformations and an unusual inheritance reminiscent of CFNS, we analyzed the EFNB1 gene in three families with CFNS. In one family, a deletion of exons 2-5 was identified in an obligate carrier male, his mildly affected brother, and in the affected females. In the two other families, missense mutations in EFNB1 were detected that lead to amino acid exchanges P54L and T111I. Both mutations are located in multimerization and receptor-interaction motifs found within the ephrin-B1 extracellular domain. In all cases, mutations were found consistently in obligate male carriers, clinically affected males, and affected heterozygous females. We conclude that mutations in EFNB1 cause CFNS.

Degradation of poly(D, L)lactide implants with or without addition of calciumphosphates in vivo

The study was aimed at examining the in vivo degradation of pure poly(D,L)lactide (PDLLA) or PDLLA with an admixture of calciumphosphates. One rod (20 x 3 x 2 mm) and one cube (3 x 2 x 2 mm) of pure PDLLA, PDLLA with tricalciumphosphate (PDLLA + TCP) or PDLLA with calciumhydrogenphosphate (PDLLA + CHP), respectively, were implanted into the dorsal muscles of 50 male Wistar Albino rats. After definite intervals (from 2nd to 72nd week), pH measurements were performed in the environment of the implants. Afterwards, the cubes with their surrounding tissues were excised for histological examinations, measurements of the outer dimensions and mechanical analyses of the explanted rods were performed. No drop of more than 0.1 pH units was detectable in the tissue surrounding any type of implants. No advantageous effect of the calciumphosphates could be proved. A mild foreign body reaction could be observed around PDLLA implants. After 72 weeks, pure PDLLA had been totally resorbed from the extracellular space, the degradation of calciumphosphate-enriched PDLLA was still in progress. A large amount of inflammations occurred in the tissues surrounding PDLLA with an admixture of slowly degrading TCP or CHP, leading to two abscesses and four fistulas at PDLLA + TCP, and two abscesses and three fistulas at PDLLA + CHP implantation site. Bending strength of pure PDLLA was constant up to the 4th week post-implantation and reduced to 60% of the initial value up to the 12th week. No traces of crystallinity could be observed during the degradation of PDLLA. As a conclusion of the study, complete resorption from the extracellular space and tissue tolerance of pure PDLLA is proved. An admixture of small calciumphosphate particles is not suitable to improve the biocompatibility of PDLLA but leads to a decrease in the mechanical characteristics.

Open reduction and internal fixation versus closed treatment and mandibulomaxillary fixation of fractures of the mandibular condylar process: a randomized, prospective, multicenter study with special evaluation of fracture level.

PURPOSE This randomized, clinical multicenter trial investigated the treatment outcomes of displaced condylar fractures, and whether radiographic fracture level was a prognostic factor in therapeutic decision-making between open reduction and internal fixation (ORIF) versus closed reduction and mandibulomaxillary fixation (CRMMF). PATIENTS AND METHODS Sixty-six patients with 79 displaced fractures (deviation of 10 degrees to 45 degrees, or shortening of the ascending ramus >or=2 mm) of the condylar process of the mandible at 7 clinical centers were enrolled. Patients were randomly allocated to CRMMF (n = 30 patients) or ORIF (n = 36 patients) treatment. The following parameters were measured 6 months after the trauma. Clinical parameters included mouth opening, protrusion, and laterotrusion. Radiographic parameters included level of the fracture, deviation of the fragment, and shortening of the ascending ramus. Subjective parameters included pain (according to a visual analogue scale), discomfort, and subjective functional impairment with a mandibular functional impairment questionnaire. RESULTS The difference in average mouth opening was 12 mm (P <or= .001) between both treatment groups. The average pain level (visual analogue scale from 0 to 100) was 25 after CRMMF, and 1 after ORIF (P <or= .001). In 53 unilateral fractures, better functional results were observed for ORIF compared with CRMMF, irrespective of fracture level (condylar base, neck, or intracapsular head). Unexpectedly, the subjective discomfort level decreased with ascending level of the fracture. In patients with bilateral condylar fractures, ORIF was especially advantageous. CONCLUSION Fractures with a deviation of 10 degrees to 45 degrees, or a shortening of the ascending ramus >or=2 mm, should be treated with ORIF, irrespective of level of the fracture.

Secretion of TFF-peptides by human salivary glands

Abstract. TFF-peptides (formerly P-domain peptides, trefoil factors) are typical secretory products of mucin-producing cells and seem to influence the rheological properties of mucous gels. Here, localization studies of TFF-peptides in human salivary glands are presented. Expression studies (polymerase chain reaction) revealed mainly TFF3 transcripts in submandibular and sublingual glands and trace amounts in parotid glands. Only low levels of expression of TFF1 could be monitored in submandibular and sublingual glands, and TFF2 transcripts were hardly detectable in all three major salivary glands. This result was partly confirmed by Western blot analysis, which only detected TFF3 in submandibular glands, but not in sublingual and parotid glands. TFF3 was also shown to be a constituent of human saliva. Immunofluorescence localized TFF3 solely in the secretory granules of serous cells of submandibular glands but not in mucous cells. This localization is remarkably similar to that of the unique low-molecular-weight mucin MUC7, which interacts with a number of oral microorganisms.

Drill Free Screws: a new form of osteosynthesis screw

Although the application of self-tapping and non self-tapping screws is virtually universal in cranio-maxillofacial surgery, the inevitable, time consuming procedure of drilling a pilot hole has some potential disadvantages, such as damage to nerves, tooth roots or tooth germs, thermal necrosis of the bone and drill bit breakage. Drill Free Screws (DFS) are a recently developed type of osteosynthesis screws, having a tip like a cork screw and specially formed cutting flutes which enable insertion of the screws without drilling. DFS 1.5 and 2 mm were inserted into discs of wood, polyvinylchloride (PVC) and porcine mandibular bone of varying thicknesses between 2 and 4 mm. The values of insertion torque and maximum torque were recorded using an electric torque tester. Thereafter, the screws were inserted with a fixed torque and uniaxial pull out tests were performed. In comparison with this, the same procedure was performed using 1.5 and 2 mm self-tapping titanium screws. Ten trials for each screw-material-combination were conducted to determine insertion torque, maximum torque and pull out analysis. The results showed that the holding power of DFS lay between 70 and 104% of the holding power of self-tapping titanium screws; only in PVC was the difference more than 15%.

Transversal Palatal Expansion Using a Palatal Distractor

Abstract.Method and Results:The method and first results of transversal expansion with a palatal distractor in adolescents and adults with transverse maxillary deficiencies are presented. In ten patients with a mean age of 25.8 years, a newly developed distractor was applied for bone-borne expansion of the two halves of the maxilla following osteotomy of the lateral walls of the maxillary sinuses and the midpalatal suture. After a 3-week distraction period, mean changes of 8.8 mm in intercanine distance (ICD), 8.6 mm in anterior dental arch width (ADA), and 8.3 mm in posterior dental arch width (PDA) were registered. 6 months after the subsequent multibracket appliance therapy, these values were found to be largely constant.Conclusion:Because of the short treatment period, the absence of relapses, and the handling simplicity for the patient, this method is recommended for clinical application.Zusammenfassung.Methode und Ergebnisse:Es werden die transversale Expansion oberer Schmalkiefer mit einem palatinalen Distraktor sowie erste Behandlungsergebnisse bei Jugendlichen und Erwachsenen beschrieben. Bei zehn durchschnittlich 25,8 Jahre alten Patienten erfolgte nach der Osteotomie der seitlichen Maxillae und der Sutura palatina mediana die Applikation eines neu entwickelten Palatinaldistraktors zur körperlichen Weitung der Oberkieferhälften. Nach einer 3-wöchigen Distraktionsphase betrugen die mittleren Veränderungen der interkaninen Distanz (ICD) 8,8 mm, der vorderen (ADA) 8,6 mm und der hinteren Zahnbogenbreite (PDA) 8,3 mm. 6 Monate nach der anschließenden kieferorthopädischen Multibandtherapie blieben diese Werte weitgehend konstant.Schlussfolgerung:Wegen der kurzen Behandlungsdauer, Rezidivfreiheit und einfachen Handhabung für den Patienten kann diese Methode für die klinische Anwendung empfohlen werden.

Influence of different pilot hole sizes on torque measurements and pullout analysis of osteosynthesis screws

When screws are inserted in thick cortical bone, a small pilot hole size, corresponding to the core diameter of the screw, can result in high torsional stress, leading to screw fracture. The aim of this study was to enlarge the drill size up to a critical pilot hole size (CPHS) which, if exceeded, means a rapid decrease in the screw holding power. 1.5 and 2 mm titanium screws were inserted in discs of polyvinylchloride (PVC), wood and porcine mandibular bone with thicknesses differing between 2 to 4 mm, using an increasing pilot hole size between 66% and 95% of the screw external diameter. Torque measurements and pullout tests were performed and the CPHS was calculated. In torque measurements, the CPHS of microscrews ranged between 83% and 85% of the screw external diameter (SED). The CPHS of miniscrews lay between 80% and 90% of SED. In pullout analysis, the CPHS of microscrews ranged between 83% and 89% of SED; the CPHS of miniscrews lay between 79% and 91% of SED. The mean of the CPHS was calculated to be approximately 85% of the SED. Up to this critical point, the pilot hole size may be increased without affecting the holding power of the screws.

Clinical applications of drill free screws in maxillofacial surgery

Drill free screws are newly designed osteosynthesis screws with specially formed tips and cutting flutes, which act like a cork-screw and can be inserted into bone without predrilling. A prospective study on 82 patients was performed in order to investigate the efficiency of mini- and micro-drill free screws (DFS) in clinical use and to find out areas in maxillofacial traumatology and orthognathic surgery, where the application of this new type of screw may be recommended. Thirty-eight Le-Fort-osteotomies, 23 central and lateral midfacial fractures and 21 fractures of the mandible were fixed using the Champy titanium micro/miniplate system and in total 518 center-drive titanium micro-DFS (1.5 mm) and 392 center-drive titanium mini-DFS (2 mm) with lengths between 4 and 7 mm. The results showed that the grip of micro- and mini-DFS was sufficient for the fixation of bone fragments in the central and lateral midface and in the mandibular area. The insertion of DFS was simple and is recommended in the area of the central midface; the insertion of the screws was difficult, but possible in the anterior mandible and in the lateral midface. The application of DFS in the mandibular angle region is not recommended.

pH-stabilization of predegraded PDLLA by an admixture of water-soluble sodiumhydrogenphosphate--results of an in vitro- and in vivo-study.

Aim of the study was to examine if the addition of buffering sodiumhydrogenphosphate to poly(D,L)lactide(PDLLA) would stabilize the pH-value in the in vivo environment of implanted material and whether this improves its biocompatibility. The material was predegraded just to the point of viscous disintegration to test the PDLLA in the moment of its most aggressive effect on the surrounding tissue. Racemic amorphous PDLLA was injection-molded with or without the admixture of 1 mol NaP per 100 mol lactate, the degradation product of PDLLA (=1 mol%) to form 20mm x 3 mm x 2mm rods. Predegradation was performed by storing the rods at 55 degrees C for 14 days, just to the point of beginning dissolution. Predegraded PDLLA or PDLLA + NaP samples were used for in vitro incubation tests, as well as for the in vivo study, where the rods were implanted into the spinal muscles of 30 male Wistar rats. Repeatedly, measurements of the pH-value were made in the incubation solutions in vitro. The surrounding tissue of the implanted samples as well as the normal contralateral muscle tissue was checked for its pH-value in a group of 3 rats, respectively, anaesthesized at various time intervals after implantation. After these measurements the implants and their surrounding tissues were excised for histological examination. In Ringers solution pH-values dropped immediately within the first week of incubation of both predegraded materials reaching -4 pH units after 4 weeks in the PDLLA containing medium, after 6 weeks in the PDLLA + NaP containing medium. Soerensen buffer slowed the pH decrease with significant differences between the material groups up to the 28th week. In vivo, the pH of the surrounding tissue was influenced by the implanted PDLLA material up to the 4th week, while the admixture of NaP resulted in a significant pH stabilization. A higher quantity of macrophages and giant cells were seen between the 2nd and 6th week after the implantation in the environment of pure PDLLA compared with PDLLA + NaP. Complete resorption of predegraded pure PDLLA or PDLLA + NaP from the extracellular space was reached 28 weeks postimplantation in vivo. Thus, sodiumhydrogenphosphate improves the biocompatibility of degrading PDLLA at the point of viscous disintegration by stabilizing the pH-value in the environment of the implants for several weeks and reducing adverse tissue reactions.

Inzidenz, Risikofaktoren und Verlauf von Sensibilitätsstörungen nach operativer Weisheitszahnentfernung

In einer Studie wurde die Inzidenz postoperativer Sensibilitätsstörungen im Versorgungsgebiet des N. alveolaris inferior und des N. lingualis nach der operativen Entfernung von 1103 unteren Weisheitszähnen und 3 retinierten Zwölfjahrmolaren bei insgesamt 687 Patienten mit normaler präoperativer Sensibilität ermittelt. Hierzu wurden die sensiblen und sensorischen Qualitäten im intra- und extraoralen Innervationsgebiet postoperativ durch eine neurologische Untersuchung objektiviert. Die anschließende Verlaufskontrolle erfolgte bis zu 35 Wochen lang. Bei allen Patienten wurden verschiedene klinische und radiologische Befunde sowie Parameter zur Operationstechnik und Anästhesie erfasst. Direkt postoperativ wurden Sensibilitätsstörungen des N. alveolaris inferior in 3,57% und des N. lingualis in 2,1% der Fälle ermittelt. Der überwiegende Teil bildete sich innerhalb des Kontrollzeitraums vollständig zurück. Weiterhin persistierende Dysästhesien waren mit 0,91% bzw. 0,37% selten und überwiegend von geringer Ausprägung. Zusätzlich wurde die Korrelation der Sensibilitätsstörungen zu den erhobenen Befunden überprüft. Für den N. alveolaris inferior konnten signifikante Häufungen bei höherem Patientenalter, abgeschlossenem Wurzelwachstum, tiefer Verlagerung, radiologischer Beziehung der Wurzeln zum Canalis mandibularis, bei schwieriger Zahnentfernung und bei intraoperativer Eröffnung des Nervenkanals festgestellt werden. Bei den Störungen des N. lingualis war eine signifikante Abhängigkeit vom Operateur und vom gewählten Anästhesieverfahren erkennbar. A study was carried out to determine the risk of dysesthesia of the inferior alveolar and of the lingual nerve after molar surgery. A total of 1103 impacted lower wisdom teeth and ¶3 impacted lower second molars were removed in 687 patients, all of whom with unaltered sensibility preoperatively. Clinical, radiological, and surgical factors of each case were recorded. Postoperative disturbances in the sensibility of the lip and tongue were evaluated by neurological examination. Follow-up was carried out for a maximum of 35 weeks. Dysesthesia of the inferior alveolar nerve occurred with an incidence of 3.57%. The lingual nerve was injured in 2.1% of patients. Most of the initially reported alterations in sensation resolved within the follow-up period. Dysesthesia of the inferior alveolar nerve persisted in 0.91%, and of the lingual nerve in 0.37%. However, the extent of the prolonged impairment was slight in general. The effect of the documented factors on the incidence of dysesthesia was analyzed. For the inferior alveolar nerve, analysis revealed significant effects in older patients, for completely developed roots, for deeply impacted teeth, in the radiological relationship of the roots and the inferior alveolar canal, for difficult surgery, and for intraoperative exposure of the nerve. The surgeon and the anesthesia had a significant influence on lingual dysesthesia.