Marginal bone loss one year after implantation: a systematic review of different loading protocols.

The aim of this study was to analyse the influence of different loading protocols on marginal bone loss (MBL). The outcomes of different implant loading protocols were assessed at 1year after implantation, with focus on MBL; protocols included immediate, immediate non-occlusal, early, and conventional loading. The search strategy resulted in 889 studies. Twenty-two of these studies fulfilled the inclusion criteria. Among the included studies, the lowest MBL was for immediately loaded implants (0.05±0.67mm) and the highest for immediate non-occlusally loaded implants (1.37±0.5mm). The results of the meta-analysis showed an estimated mean MBL of 0.457mm (95% confidence interval (CI) 0.133-0.781) for immediate loading, 0.390mm (95% CI 0.240-0.540) for immediate non-occlusal loading, 0.488mm (95% CI 0.289-0.687) for early loading (>2 days to <3 months), and 0.852mm (95% CI 0.429-1.275) for conventional loading (>3 months) implant protocols. The lowest decrease in 1-year implant survival per millimetre increase in MBL was observed for immediate loading and the highest for conventional loading. Conventional loading showed a significantly higher MBL than the other three loading protocols. This systematic review and meta-analysis indicates that the immediate loading protocol is a reasonable alternative to the conventional loading protocol.

Diagnosing peri-implant disease using the tongue as a 24/7 detector.

Our ability of screening broad communities for clinically asymptomatic diseases critically drives population health. Sensory chewing gums are presented targeting the tongue as 24/7 detector allowing diagnosis by "anyone, anywhere, anytime". The chewing gum contains peptide sensors consisting of a protease cleavable linker in between a bitter substance and a microparticle. Matrix metalloproteinases in the oral cavity, as upregulated in peri-implant disease, specifically target the protease cleavable linker while chewing the gum, thereby generating bitterness for detection by the tongue. The peptide sensors prove significant success in discriminating saliva collected from patients with peri-implant disease versus clinically asymptomatic volunteers. Superior outcome is demonstrated over commercially available protease-based tests in saliva. "Anyone, anywhere, anytime" diagnostics are within reach for oral inflammation. Expanding this platform technology to other diseases in the future features this diagnostic as a massive screening tool potentially maximizing impact on population health.Early detection of gum inflammation caused by dental implants helps prevent tissue damage. Here, the authors present a peptide sensor that generates a bitter taste when cleaved by proteases present in peri-implant disease, embed it in a chewing gum, and compare the probe to existing sensors using patient saliva.

Palatal piezosurgical window osteotomy for maxillary sinus augmentation.

This technical note describes a new surgical technique for a palatal approach to the maxillary sinus for a vertical augmentation prior to dental implant placement. In 12 fully or partially edentulous patients (seven women, five men), 16 palatal sinus elevations were performed. After elevation of palatal full-thickness flap a rectangular access window was cut with a piezosurgical device. The raised sinus cavity was augmented with a synthetic nano-structured hydroxyapatite-based graft material. No harm occurred to the greater palatine artery or the sinus membrane. The vestibular and periimplant gingiva were preserved and there was no disharmonious soft tissue distortion or massive scar formation. Swelling and bleeding were minimal. Primary stability was achieved for all but one implant. This technique may be an alternative to other sinus augmentation approaches in cases where enough transversal width of the posterior alveolar crest is available.

Maxillary sinus grafting with a nano-structured biomaterial: preliminary clinical and histological results.

BACKGROUND: In this study the potential of a new and entirely synthetic, nano-structured hydroxyapatite-based biomaterial for sinus floor augmentation is evaluated. METHODS: 20 sinus floor elevations were carried out in a total of 20 patients. After a healing period of 6 months, in 10 cases cylinder-shaped bone biopsies were taken from the augmented maxillary region using trephine burs. RESULTS: The healing period progressed without any complications. General and specific histological analysis of the bone biopsies showed a high osteoclast activity at the margin of the biomaterial which was well integrated into the newly formed bone. CONCLUSION: This study demonstrates that new trabecular bone is formed after grafting with the nanocrystalline bone substitute after 6 months. Ongoing histomorphological studies are necessary to quantify the biomaterial-bone ratio and the exact amount of newly built bone in the augmented cavity after 6 months.

Er:YAG laser osteotomy: preliminary clinical and histological results of a new technique for contact-free bone surgery.

BACKGROUND: The purpose of this retrospective study was to evaluate the surgical performance, clinical usability and outcome of a new variable square pulsed (VSP) Er:YAG laser for bone cutting in oral and maxillofacial surgery. MATERIALS AND METHODS: In 40 patients an Er:YAG laser with pulse energy of 1,000 mJ, pulse duration of 300 mus and a frequency of 12 Hz was used for different intraoral osteotomies. The spot size was 0.9 mm, and the handpiece was kept at a distance of 10 mm from the bone surface. Additionally, histological analyses of the fresh osteotomy rims of lasered bone were performed. RESULTS: Er:YAG laser osteotomy revealed a remarkable cutting efficiency without any visible, negative, thermal side effects. There was no damage of adjacent soft tissue structures. However, depth control was limited to visual inspection. Histologically, a 5- to 10-microm-wide zone of a characteristic laser fingerprint appeared on the cut edges. However, there was no sign of thermal tissue damage to the underlying bone structures. CONCLUSIONS: VSP Er:YAG laser osteotomy is clinically practicable without any signs of charred tissue and wound healing disturbances. However, the lack of depth control and the necessity for careful handling are still technical limitations to be overcome.

Piezoosteotomy in orthognathic surgery versus conventional saw and chisel osteotomy.

INTRODUCTION: Piezoosteotomy was assessed as alternative osteotomy method in orthognathic surgery regarding handling, time requirement, nerve and vessel impairment. MATERIALS AND METHODS: In this comparative clinical experience, 90 patient's orthognathic surgery procedures were performed in typical distribution prospectively by piezoosteotomy: 34 (38%) monosegment, 47 (52%) segmented LeFortI osteotomies, 94 (52%) sagittal split osteotomies, 11 (12%) symphyseal, and 4 (2%) mandibular body osteotomies. As controls served 90 retrospective patients with conventional saw and chisel osteotomy: 58 (64%) monosegment, 27 (30%) segmented LeFortI osteotomies, 130 (72%) sagittal split, and 4 (4%) symphyseal osteotomies. RESULTS AND DISCUSSION: Piezoosteotomies were individually designed to interdigitate the jaw segments after repositioning. The pterygomaxillary suture weakened angulated tools; auxiliary chisels were required in 100% of cases for the nasal septum and lateral nasal walls, in 33% for pterygoid processes. The dorsal maxilla as the pterygoid process were easily reduced; 15% mandibular osteotomies required sawing, while the lingual dorsal osteotomy was performed by manual feedback due to limited visibility. Bloodloss decreased from average 537 +/- 208 ml vs. 772 +/- 338 ml (p = 0.0001). Operation time remained unchanged: 223 +/- 70 min vs. 238 +/- 60 min (p = 0.2) for a conventional bimaxillary procedure. Clinical courses and reossification were unobtrusive. Alveolar inferior nerve sensitivity was retained in 98% of the piezoosteotomy collective versus 84% of controls (p = 0.0001) at 3 months postoperative testing. CONCLUSION: Piezoelectric osteotomy did not prolong the operation and reduced blood loss as alveolar nerve impairment. A few patients required additional sawing or chisel. Piezoelectric screw insertion as complex osteotomies may be initiated to simplify the procedure and increase segment interdigitation after repositioning as to minimize the osteofixation time and dimensions.

[Ultrasonic bone cutting in oral surgery: a review of 60 cases]. / Ultraschallbasiertes Knochenschneiden in der Oralchirurgie: eine Ubersicht anhand von 60 Patientenfällen.

PURPOSE: Surgical reconstruction of bony defects in the oral cavity can often be challenging since thin and fragile bony structures are especially prone to fracture cased by bulky cutting tips or the application of significant pressure by conventional mechanical instruments. The risk of accidental damage to adjacent soft tissue structures, such as nerves, by a dental drill or saw is also extremely high. The use of modulated ultrasound (piezosurgery) makes it possible to overcome such complications as a result of the precise and minimally invasive surgery technique which is limited to mineralized hard tissue. MATERIALS AND METHODS: In 60 patients (38 male, 22 female) a piezosurgery device was used for different bone augmentation procedures before dental implant placement. The instrument uses modulated ultrasound (25 - 30 kHz) and the amplitude of the working tip ranges from 60 mum to 200 mum. The device was employed for sinus floor elevation (25), alveolar ridge augmentation using an autogenous block graft (25), alveolar ridge splitting (5) or lateralization of the alveolar nerve (5). Physiological sodium chloride was used as a cooling solution. For all osteotomies mode boosted burst c and pump 5 were used. RESULTS: Piezoelectric osteotomy permitted micrometric selective cutting and a clear surgical site due to the cavitation effect created by the cooling solution and the oscillating tip. No excessive bleeding was encountered. The risk of accidental soft tissue harm, such as perforating the sinus membrane or damaging adjacent nerves, was definitely lower than in the case of a conventional bur. No serious complications were encountered in the postoperative wound healing process after 2, 14, 30 and 90 days. However, the surgical procedures were time-consuming. CONCLUSION: Piezosurgery is an advantageous osteotomy technique for delicate structures in the oral and maxillofacial region. With respect to osteotomies of thin and fragile bones, the application of ultrasound is superior to other mechanical instruments because of the extremely precise and virtually arbitrary cut geometries, easy handling, efficient bone ablation and minimal accidental damage to adjacent soft tissue structures.

[Brachytherapy of the prostate cancer]. / Brachytherapie des Prostatakarzinoms.

Prostate cancer (PCA) is the most frequent onlocological disease in men. Every year there are ca. 202.000 new cases of prostate cancer in Europe. Curative treatment of this carcinoma via brachytherapy is becoming increasingly significant (20-30% of all curative approaches). Initial staging and thus allocation to risk groups prior to the commencement of therapy is esspecially important for successful brachytherapy treatment.Low-dose-rate (LDR) brachytherapy (i.e. SEED implantation) distinguishes itself both with respect to the procedure as well as the indication from high-dose-rate brachytherapy (afterloading procedure). Both treatment procedures are employed as monotherapy as well as in combination with external radiation.LDR monotherapy is reported to achieve biochemically relapse-free outcome of up to 90% in low-risk tumours during 10-year follow-up periods. Combined HDR tele- and brachytherapy is reported to achieve a biochemically relapse-free outcome of 80-90% with intermediate- and high-risk tumours in long-term follow-up.While randomized studies are as yet missing, it is still possible to derive the following application algorithms from monitoring studies and cohort studies: application of LDR monobrachytherapy must be restricted to low-risk tumorus. Combined HDR tele- and brachytherapy can be sucessfully applied in cases of intermediate- and high-risk tumours. The outcome depends significantly on the initial, pre-therapy PSA value and Gleason score. Posttherapeutically, the nadir value is crucial with respect to predicting the biochemically relapse-free outcome.

[Extended sentinel lymph node dissection in radical prostatectomy for prostate cancer: a study in the Kiel risk population]. / Die extendierte Sentinel-Lymphadenektomie im Rahmen der radikalen Prostatektomie? : Untersuchungen im Kieler Risikokollektiv.

Extended lymph node dissection during radical prostatectomy for prostate cancer remains a disputed area. Sentinel lymph scans help identify the first lymph node stages in the lymph drainage of the prostate. This study was designed to investigate the detection rate of lymph node metastasis by extended lymph node dissection and sentinel lymph node scanning in patients undergoing radical retropubic prostatectomy (RRP) for localized prostate cancer. In this study at our department from 2005 to 2006, a total of 108 patients with localized prostate carcinoma were treated with radical prostatectomy including extended lymph node dissection. A sentinel lymph node scan with 160 MBq of technetium-99m-Nanocoll (Tc) was performed 1 day before surgery. A C-Trak gamma probe (AEA Technologies, Morgan Hills, CA, USA) was used intraoperatively to detect the sentinel lymph nodes. Scan findings were correlated with tumor stage, Gleason score, prostate-specific antigen (PSA) level, and histological lymph node status. Scans revealed sentinel lymph nodes on the film 2 h after Tc administration in 98 of 108 patients (91%). Histologically proven lymph node metastases were detected in 15 of those 98 patients (15%) with a positive sentinel scan. Those 15 patients had a PSA level greater than 10 ng/ml or a Gleason score greater than 6 and at least a pT2 tumor. Specifically, six patients had a pT2 tumor, and nine patients had a pT3 tumor. Of patients placed in a risk group defined as PSA above 10 ng/ml or Gleason score greater than 6, 15 out of 50 patients (30%) had sentinel positive lymph nodes with metastasis. These data suggest that extended sentinel lymph node dissection helps identify lymph node metastasis in patients with PSA above 10 ng/ml or a Gleason score above 6 in 30% of cases. Further studies will show whether these numbers will hold true in patients undergoing radical prostatectomy for prostate cancer.

Finite element simulation of the human mandible: the role of (natural) teeth.

INTRODUCTION: Individual bone quality depends on genetic, biological, and mechanical influencing factors, where the latter is accessible via Finite Element Simulation. This work is part of an interdisciplinary research project with the purpose of stepwise refinement towards anatomical reality. This approach opened the door for many interrelated applications such as atrophy of the jaw bone, periodontology, implantology, or TMJ disorders. This lecture is dedicated to the influence of dental anatomy on mandibular biomechanics. MATERIALS AND METHODS: In general, biomechanical simulation requires reconstruction of the individual anatomy, implementation of the inhomogeneous and anisotropic material law of bone, and realization of the load case due to tooth, muscle and joint forces. The simulation chain ranges from image processing of CT data up to specifically adapted post-processing of the simulation results. In spite of ongoing research, there is still a fundamental difference of dental implants compared to natural teeth: the periodontal ligament (PDL) present at the interface between teeth and mandibular corpus. Due to its thickness of about 0.2 mm, the PDL was introduced to the simulation model by a special semiautomatic procedure. RESULTS: Simulations "with and without PDL" proved remarkable force absorption due to the PDL, as well as qualitative changes of the stress/strain profiles of the alveolar ridge. Concerning the simulation without PDL, the observed high compressive strains at the adjacent bone were in agreement with regions of frequent implant failure. CONCLUSION: The PDL is essential for the structural behavior of the human mandible. Based on the mechanical adaptation of bone, the comparison of the simulation with and without PDL provided special insight to the changes due to dental implants, in particular implant loss and bone resorption. Finally, the simulation will serve as a virtual platform for further evaluation (a) of implant design (b) of implant placement.

Mandibular finite element simulation as a tool for trauma surgery.

PURPOSE: Despite remarkable progress within the last decade, the treatment of mandibular fractures is still a highly discussed topic in oral and cranio-maxillofacial surgery. The possible traumatologic scenarios are characterized by high variability. A current project is focused on "resimulation" of traumatologic cases given by clinical radiographs by means of finite element method. METHODS: The applied finite element model of the mandible is very refined, providing detailed dental anatomy especially of the periodontal ligament. The mandible was modelled as inhomogeneous and anisotropic. The temporomandibular joints were realized as simplified joint capsules, wherein the mandibular condyles are freely mobile with certain limitations. The user has the choice of 5 regions on the mandibular surface where the virtual injury can be inflicted. Power and direction of the impact force vector can be set at will. The masticatoy system including the digastrics and the mylohyoid muscles can be activated. RESULTS: The situations given by radiographs could be "reproduced" by a simulation scenario characterized by high compressive strain at the location of fractures. If masticatory muscles were activated and teeth clenched, the stress/strain profiles were qualitatively changed. DISCUSSION: The approach may be of benefit for optimized behavior with regard to certain sports or vocations. For forensic analysis, the method will contribute by elimination of scenarios not matching the given fracture locations. Nevertheless, the immediate purpose of our approach is a better understanding of the injured organ's condition. Fractures of bone as an adaptive biological tissue differ fundamentally from mechanical failure in engineering. Many of our trauma simulations showed elevated stress/strain around the fracture, leading to the suggestion of weakened bone there. This finding was confirmed by surgical observation.

[Pelvic tumors in the eyes of urologists]. / Raumforderungen im kleinen Becken aus Sicht des Urologen.

Pelvic tumors originating from outside the urinary tract commonly invade the urogenital organs by direct extension mainly because of the close relationships between the pelvic organs. Benign tumors such as endometrial myoma, ovarian cyst and adenoma of the colon might lead to the development of urogenital symptoms. This is also the case with malignant tumors of the uterus, ovaries, cervix and colon where infiltration of the urogenital organs might be noted. The most commonly mentioned symptoms involve incontinence, infections, obstructive symptoms, and in terminal cases those of renal failure. These are the symptoms that lead to the diagnosis of the primary tumor. It has to be kept in mind that urogenital tumors with such symptoms have to be included in the differential diagnosis. The therapeutic measures are directed at first to relieve the symptoms before intending to deal with the causative source. An example is the development of hydronephrosis, where the initial measure has to be the immediate relief of the obstruction through draining of either the kidney or the urinary bladder. The possibility of eradicating the tumor is then to be discussed after relieving the obstruction.

[Etiology and pathophysiology of male stress incontinence]. / Atiologie und Pathophysiologie der Belastungsinkontinenz beim Mann.

Stress urinary incontinence is rare in men. Despite the improvements in diagnostic approaches to prostate diseases and surgical interventions on the prostate, stress incontinence has tended to increase in recent decades. The most frightening operative complication for both the patient and the surgeon is incontinence, which is one of the important factors in the treatment of the affected patients. The limited degree of continence considerably lowers the quality of life for the affected men and their partners. There is little information available about the pathophysiology of iatrogenic stress incontinence, which more likely affects older men rather than young men. The available information is based on a few experimental studies. Besides the direct damage to the muscular or neurological component of the external sphincter, insufficient length of the functional urethra and impaired bladder function seem to play an important role in the genesis of postoperative incontinence. In order to improve the postoperative continence status after radical prostatectomy a number of different operative modifications have been introduced. Preservation of the bladder neck, puboprostatic ligaments, and the neurovascular bundle as well as leaving the tips of the seminal vesicles seem to have a positive impact on the degree of postoperative continence.

[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.

[Treatment of intraoral hemangiomas with the CO2 laser]. / Therapie intraoraler Hämangiome mit dem CO2-Laser.

Intra-oral haemangiomas can lead to intra-operative bleeding while being excised conventionally with a scalpel. Therefore excision with CO2-Laser using coagulating effects and vaporisation of soft-tissues has been introduced. 52 intra-oral haemangiomas were excised minimal invasively and without relapse. With CO2-Laser no complications were seen postoperatively but the healing period was prolonged.

[Proctological diseases in routine urologic practice]. / Proktologische Erkrankungen im urologischen Alltag

Nearly two third of adults will suffer from proctologic complaints. The same symptoms could also indicate or mask an anorectal carcinoma. Therefore, the first priority should be to exclude the possibility of a neoplasm of the colon, rectum and the anal canal. Knowledge of the specific anatomy of the anal canal and the patient's history will lead to an exact proctologic diagnosis: perianal thrombosis, acute thrombosed prolapsed haemorrhoidal plexus, an anal fissure, abscess and fistula are located within the highly sensitive anoderma and are characterized by pain. Perianal thrombosis, chronic fissure, abscess and fistula require surgery. Conservative treatment is the choice for an acute anal fissure, haemorrhoids grade I-II. Haemorrhoids II-III require surgery, e.g. by haemorrhoidal artery ligation, open or closed resection of the haemorrhoidal plexus, reconstruction of the anal canal or stapled mucosectomy. Perianal diseases such as perianal tags, fibroma or condylomata acuminata are easily diagnosed and treated. Secondary perianal eczema requires treatment of the underlying proctologic disease. If it persists, a biopsy is required.