Bone formation in mono cortical mandibular critical size defects after augmentation with two synthetic nanostructured and one xenogenous hydroxyapatite bone substitute - in vivo animal study.

OBJECTIVES: Healing characteristics as well as level of tissue integration and degradation of two different nanostructured hydroxyapatite bone substitute materials (BSM) in comparison with a deproteinized hydroxyapatite bovine BSM were evaluated in an in vivo animal experiment. MATERIAL AND METHODS: In the posterior mandible of 18 minipigs, bilateral mono cortical critical size bone defects were created. Randomized augmentation procedures with NanoBone(®) (NHA1), Ostim(®) (NHA2) or Bio-Oss(®) (DBBM) were conducted (each material n = 12). Samples were analyzed after five (each material n = 6) and 8 months (each material n = 6). Defect healing, formation of soft tissue and bone as well as the amount of remaining respective BSM were quantified both macro- and microscopically. RESULTS: For NHA2, the residual bone defect after 5 weeks was significantly less compared to NHA1 or DBBM. There was no difference in residual BSM between NHA1 and DBBM, but the amount in NHA2 was significantly lower. NHA2 also showed the least amount of soft tissue and the highest amount of new bone after 5 weeks. Eight months after implantation, no significant differences in the amount of residual bone defects, in soft tissue or in bone formation were detected between the groups. Again, NHA2 showed significant less residual material than NHA1 and DBBM. DISCUSSION: We observed non-significant differences in the biological hard tissue response of NHA1 and DBBM. The water-soluble NHA2 initially induced an increased amount of new bone but was highly compressed which may have a negative effect in less stable augmentations of the jaw.

The "Lumpy Jaw" Disease-Treatment and Diagnostical Challenge of Actinomycotic Osteomyelitis.

Background: Osteomyelitis is a serious entity that can occur in many different locations. Especially in the mandible, osteomyelitis can show different clinical courses, which differ clearly from other anatomical regions in terms of severity and treatment. Osteomyelitis in the mandible is often caused by mixed species of the oral cavity. A species causing subacute/chronic osteomyelitis can be actinomyces. Actinomycotic osteomyelitis of the jaw represents a diagnostic and treatment challenging disease. Conclusion: This article describes our perspective on the therapy pillars treating actinomycotic osteomyelitis. The rapid introduction of the two therapeutic elements (antibiosis/surgical therapy) is crucial regarding the outcome of this entity.

Distribution and impaction patterns of third molars in a sample of German population: Retrospective analysis in a high turnover maxillofacial department.

BACKGROUND: The surgical removal of impacted third molars is considered a routine procedure for oral and maxillofacial surgeons. However, the distribution of impacted molars varies among different populations. A study into impaction patterns in the German population is currently not described. The aim of this retrospective study is to determine patterns of impacted third molars in a sample of German population, to identify gender and age specific differences as well as further risk factors for impacted molar extraction and to compare these results with other studies. MATERIALS AND METHODS: The clinical findings and digital panoramic radiographs of 84 patients with a total of 243 impacted third molars that had been subjected for tooth extraction, from January to September 2023, were collected and analyzed. All third molars were analyzed according to Winter´s angulation, Pell and Gregory Score of depth and relationship to ramus. Furthermore, inferior alveolar nerve and maxillary sinus proximity were identified through a newly developed risk score and an analysis of patient´s gender and age regarding impaction patterns was performed. RESULTS: No significant gender specific differences were found regarding the impaction patterns. Third molar angulations significantly differed regarding patient´s age (cut-off 26 years). In comparison, third molar depth, bone coverage, nerve approximity and angulation patterns differed from the results of other populations. CONCLUSION: The results of this study can serve as a baseline for further studies of third molar impactions in the German population to minimize perioperative complications in impacted third molar surgery.

Risk factor analysis for perioperative complications in impacted third molar surgery - a single center experience.

BACKGROUND: The surgical removal of impacted third molars is usually carried out by an oral/maxillofacial surgeon. Two specific risks of surgical removal of impacted third molars are oroantral communication (OAC) when extracting ​​upper third molars and hypesthesia of the inferior alveolar nerve (IAN) ​​when extracting lower third molars. The aim of this study is to determine the distribution of complications in deeply impacted third molar surgery, to identify specific risk factors influencing the most common perioperative (OAC, IAN hypesthesia) and to compare these results with other studies. MATERIALS AND METHODS: The clinical findings, digital panoramic radiographs, intra- and postoperative data of 80 patients with a total of 232 impacted third molars that had been subjected for tooth extraction, from December 2022 and August 2023, were collected and analyzed. Perioperative complications (IAN hypesthesia, OAC, hypesthesia lingual nerve, postoperative bleeding, postoperative infection) were identified. A risk analysis for OAC and IAN hypesthesia was performed regarding perioperative data. RESULTS: Overall, the rate of OAC for the right upper third molar was 12.8% and for the left upper third molar 15.6%. The complication rates regarding transient hypesthesia were 8.1% for the left IAN and 7.3% for the right IAN. The distance to maxillary sinus, the depth score according to Pell and Gregory, the bone coverage score, the operation time, the tooth's angulation and the type of surgeon (oral surgeon, DMD) were identified as significant risk factors for the occurrence of OAC. The minimum distance to IAN, the bone coverage score, the total operation time and the operation by an oral surgeon (DMD) were identified as significant risk factors for hypesthesia of the IAN. CONCLUSION: Next to the risk factors from above, the present study is one of the first showing that patients who were primarily operated on by an oral surgeon (DMD) and not a maxillofacial surgeon (MD, DMD) showed higher rates of OAC and IAN hypesthesia in impacted third molar extraction. The results of this study can serve as a baseline for further studies to investigate complication patterns in impacted third molar surgery.

Large Complex Odontoma in the Angulus Mandibulae - Intraoral Enucleation as an Alternative to Mandibular Continuity Resection.

BACKGROUND: Odontomas are among the most common odontogenic tumors and are generally considered as hamartomatous odontogenic lesions. These tumors can be histopathologically divided into complex odontomas and compound odontomas based on their composition. Odontomas show a slow growing behavior and typically lack characteristic symptoms. The standard surgical treatment for large odontogenic tumors is a mandibular (continuity) resection followed by primary or secondary plastic reconstruction. CASE REPORT: A 22-year-old male presented to the Department of maxillofacial surgery with an increasing feeling of pressure in the left mandible. An orthopantomogram revealed a large complex odontoma rg 038. Instead of mandible continuity resection an alternative minimally invasive technique/approach (intraoral) with a trapezoidal bone flap for the enucleation of an odontoma of the mandibular angle with subsequent flap reimplantation and osteosynthesis was performed. CONCLUSION: Surgical enucleation of large mandibular odontoma with a continuity resection through an extraoral approach represents the surgical standard treatment of this entity. The present case report describes an alternative minimally invasive technique/approach. This technique may reduce surgical risks of the continuity resection through an extraoral approach (nerve damage, scarring) and can improve the long-term stability of the mandible by bone preservation.

Treatment Challenges in Soft Tissue Reconstruction in Patients With MRONJ - The Nasolabial Flap.

BACKGROUND/AIM: Antiresorptive drugs (e.g., bisphosphonates, denosumab) are crucial in the treatment of oncological diseases. However, these antiresorptive drugs can cause medication-related osteonecrosis of the jaw (MRONJ). MRONJ is a challenging disease regarding the soft tissue defect treatment. There are various surgical reconstruction techniques. One of them is the nasolabial flap. CASE REPORT: The present case report describes a 76-year-old female suffering from MRONJ leading to a progressive abscess of the mandible as well as an intra/extraoral fistula with extent to the chin region. Surgical splitting of the abscess was performed immediately. In the further course, a surgical decortication of the mandible with soft tissue defect treatment using a mucoperiosteal flap was performed. Intraoperatively, the bone of the mandible showed severe necrotic defects in multiple locations. Therefore, a continuity resection of the mandible with an insertion of a reconstruction plate was performed. Postoperatively, however, there was a progressive wound dehiscence. Due to the persisting regression of the gingival mucosa, the soft tissue defect was treated with a caudally pedicled bilateral nasolabial flap. The further clinical follow-up showed no recurrence of MRONJ with a well-healed nasolabial flap. CONCLUSION: In addition to mucoperiosteal flaps and microvascular reconstructions, the nasolabial flap can be a sufficient surgical therapy for intraoral soft tissue defect reconstruction.

Metastasis of a Solitary Fibrous Tumor in the Mandible: A Case Report.

BACKGROUND/AIM: The solitary fibrous tumor (SFT) is a mesenchymal neoplasm and belongs to the group of soft tissue sarcomas. The SFT is characterized by indolent, slowly progressive growth and manifests itself clinically by compression of neighboring structures. The treatment of choice is surgical removal of the tumor. In advanced stages, there is also the possibility of chemotherapy, systemic therapy, or immunotherapy, as well as radiotherapy. Depending on their location and severity, SFTs show different recurrence rates and survival functions. CASE REPORT: The present case report shows an extremely rare localization of a low-risk SFT in the floor of the mouth. Despite complete surgical removal of the SFT, the patient showed a metastasis of the SFT in the mandible two years postoperatively. Therefore, this case report shows that even a low-risk SFT in the localized stage can metastasize despite of total surgical removal. Consequently, SFTs of the head and neck region require close clinical and imaging follow-up. CONCLUSION: Although the localization of the SFT in the oral cavity is a rarity, this entity should be included in the differential diagnosis in the case of long-term space-occupying processes in the head and neck region. This report is the first regarding metastasis of a SFT to the mandible.

Chronic Maxillary Sinusitis Caused by an Aspergilloma in the Context of Inadequately Treated Type II Diabetes Mellitus.

BACKGROUND/AIM: The prevalence of chronic sinusitis (CS) in Europe is greater than 10%. The causes of CS are diverse. In some cases, dental treatment in the maxilla as well as fungal infection, such as aspergilloma, can lead to CS. Inadequately treated illnesses, such as type II diabetes, are known risk factors for atypical infections. CASE REPORT: The present case report describes a 72-year-old female suffering from CS in the maxillary sinus. A few years earlier, the patient received endodontic treatment of a maxillary tooth. For further diagnostics a CT-scan was performed showing an obstructed maxillary sinus on the left due to a polypoid tumor. The patient had been suffering from type II diabetes that had been inadequately treated for several years. The patient was surgically treated with an osteoplasty of the maxillary sinus combined with a supraturbinal antrostomy. Histopathological findings revealed an aspergilloma. The surgical therapy was supplemented by antimycotic therapy. In addition, the patient received antidiabetic treatment leading towards stable blood sugar levels. CONCLUSION: Rare entities, such as aspergillomas, can also be the cause of CS. In particular, patients with previous illnesses relevant to the immune system are predisposed for Aspergilloma after dental treatment leading to CS.

Subacute Actinomycotic Osteomyelitis of the Mandible - An Underreported Disease?

BACKGROUND/AIM: Cervicofacial actinomycosis is a rare entity. The manifestation of this disease in the context of osteomyelitis in the mandible is even rarer. CASE REPORT: This case report describes a 70-year-old female with a painful swelling in the left mandible. The swelling was initially noticed four weeks ago. Furthermore, the patient reported problems with medications concerning her type II diabetes mellitus. Due to multiple decayed teeth, the patient had multiple teeth extracted in recent years, including teeth 36-38 in the left mandible. Orthopantogram (OPG) and computed tomography (CT) scan showed an unspecific osteolysis in the left mandible. An incisional biopsy was performed revealing subacute necrotizing osteomyelitis of the mandible due to actinomyces. Furthermore, the patient was treated with open debridement, curettage, and decortication as well as long term antibiotics (amoxicillin + clavulanic acid) for 6 weeks. In addition, type II diabetes mellitus could be controlled with various medications (Metformin, Dapagliflozin). Clinical follow-up revealed no evidence of recurrence. CONCLUSION: Even though actinomycosis is rare, it should be included in the differential diagnosis of unspecific osteomyelitis of the jaw. Antibiotics and surgical decortication are the crucial therapy pillars when treating actinomycotic osteomyelitis in the mandible.

Immunohistochemical characterization of nanocrystalline hydroxyapatite silica gel (NanoBone(r)) osteogenesis: a study on biopsies from human jaws.

OBJECTIVES: Bone substitute biomaterials may be osteogenic, osteoconductive or osteoinductive. To test for these probable characteristics in a new nanoporous grafting material consisting of nanocrystalline hydroxyapatite embedded in a porous silica gel matrix (NanoBone(s)), applied in humans, we studied biopsies from 12 patients before dental implantation following various orofacial augmentation techniques with healing times of between 3.5 and 12 months. MATERIAL AND METHODS: Sections from decalcified specimens were investigated using histology, histochemistry [periodic acid Schiff, alcian blue staining and tartrate-resistant acid phosphatase (TRAP)] and immunohistochemistry, with markers for osteogenesis, bone remodelling, resorption and vessel walls (alkaline phosphatase, bone morphogenetic protein-2, collagen type I, ED1, osteocalcin, osteopontin, runx2 and Von-Willebrand factor). RESULTS: Histologically, four specific stages of graft transformation into lamellar bone could be characterized. During early stages of healing, bone matrix proteins were absorbed by NanoBone(s) granules, forming a proteinaceous matrix, which was invaded by small vessels and cells. We assume that the deposition of these molecules promotes early osteogenesis in and around NanoBone(s) and supports the concomitant degradation probably by osteoclast-like cells. TRAP-positive osteoclast-like cells were localized directly on the granular surfaces. Runx2-immunoreactive pre-osteoblasts, which are probably involved in direct osteogenesis forming woven bone that is later transformed into lamellar bone, were attracted. Graft resorption and bone apposition around the graft granules appear concomitantly. CONCLUSIONS: We postulate that NanoBone(s) has osteoconductive and biomimetic properties and is integrated into the host's physiological bone turnover at a very early stage.

Biomechanical comparison of a multidirectional locking plate and conventional plates for the osteosynthesis of mandibular angle fractures-A preliminary study.

PURPOSE: The objective of surgical fracture management is to reduce and fixate fractures accurately and rapidly. Two osteosynthesis plates are usually used in the treatment of mandibular angle fractures to enhance torsional stiffness. We conducted biomechanical tests under static and cyclic loading to assess whether a single locking plate is as efficacious as two conventional plates in the osteosynthesis of mandibular angle fractures. MATERIALS AND METHODS: Fracture gaps were created in synthetic mandible replicas. After pretests, the stiffness of a single locking plate and different types of non-locking, two-plate systems was assessed and compared under static and cyclic loading. The plates were subjected to a maximum static load of 750 N and underwent cyclic loading at a constant force of 400 N during a maximum of 500,000 cycles. RESULTS: No plastic deformation occurred in the static tests. Both types of osteosynthesis showed high static stability. The locking plate was significantly stiffer than the non-locking plates (p = 0.0079). Cyclic loading tests did not reveal any significant differences. CONCLUSION: Within the limitations of this preliminary study, a single locking miniplate appears to be as efficacious in biomechanical tests as non-locking, two-plate systems for the management of mandibular angle fractures.

Repair of bone defects by applying biomatrices with and without autologous osteoblasts.

QUESTION: Is it possible to stimulate osteoconduction and osteogenesis to improve bone formation in critical-size defects in order to avoid bone grafting? MATERIAL AND METHODS: Full thickness, critical-sized defects were created in the anterior mandible of 16 adult mini-pigs. The defects were filled with a new bioactive matrix (60% hydroxyapatite and 40% beta-tricalciumphosphate), produced by an innovative low temperature sol-gel-process (120 degrees C). The biomatrix was tested alone and in combination with cultured autologous osteoblasts. In a control group, periosteum was the only bone producing source. Five weeks postoperatively, the animals were sacrificed and the defects analysed macroscopically, histologically and radiographically. RESULTS: The highest rate of new bone formation was in the biomatrix group without osteoblasts (73% of the former defect). The biomatrix was degraded at the same speed as new bone was laid down. In the control group, bone formation of only 59% was observed. Additional transplantation of autologous osteoblasts in combination with the biomatrix did not result in more bone production than in the control group(!). CONCLUSION: This new bioactive calciumphosphate matrix seems to be a promising bone replacement material.

Blood supply of the mandibular cortex: an experimental study in Göttingen minipigs with special reference to the condyle.

INTRODUCTION: Blood supply of the mandible is an important factor that influences bone growth and bone repair. MATERIAL AND METHODS: An experimental study was carried out in 24 mandibles of 12 Göttingen minipigs to study the blood supply of the mandibular cortex. RESULTS: Endosteal blood supply prevails in the cranial part of the mandible including the condyle, whilst periosteal blood supply predominates in the caudal part of the mandible, the body. The two forms of blood supply are in balance in the ascending ramus and the angle of the mandible. CONCLUSION: The mandibular cortex can be divided into three parts, each having different sources of blood supply. The results of this study may be of significance for man and could help to understand some pathological disorders of the mandible.

Lateral augmentation of the mandible in minipigs with a synthetic nanostructured hydroxyapatite block.

The purpose of this study was to evaluate biomaterial degradation and new bone formation after implantation of a nanostructured hydroxyapatite (HA) grafting block. Furthermore, physical characteristics of the biomaterial were measured. The biomaterial consists of nanostructured HA embedded in a porous matrix of silica (SiO(2) ) gel. The blocks with two different contents of silica (group A: 24 wt % and group B: 39 wt %) were fixed with titanium screws at the lateral aspect of the mandible of minipigs (n = 5). The specific surface areas of both blocks were measured using Brunauer-Emmett-Teller (BET) equation and mercury intrusion. In all animals, the wound healing was uneventful. After 5 weeks, the biomaterial percentage was 51.5% ± 12.1% for group A and 33.2% ± 5.9% for group B (p = 0.017). New bone formation accounted to 7.6% ± 6.0% for group A and 15.3% ± 8.3% for group B (p = 0.126) after 5 weeks. After 10 weeks, further resorption of the biomaterial led to percentages of 30.6% ± 10.0% for group A and 12.1% ± 6.7% for group B (p = 0.000). After 10 weeks, new bone formations were measured to be 34.1% ± 10.8% in group A and 39.9% ± 13.5% in group B (p = 0.383). The rate of degradation of the biomaterial is controlled by the composition of the material. A higher content of silica gel matrix leads to faster degradation of the biomaterial. The formation of new bone failed to show a significant difference between both groups.

A preliminary study in osteoinduction by a nano-crystalline hydroxyapatite in the mini pig.

To test the probable osteoinductive properties of NanoBone, a new highly non-sintered porous nano-crystalline hydroxylapatite bone substitute embedded into a silica gel matrix, granules were implanted subcutaneously and intramuscularly into the back region of 18 mini pigs. After periods of 5 and 10 weeks as well as 4 and 8 months, implantation sites were investigated using histological and histomorphometric procedures. Signs of early osteogenesis could already be detected after 5 weeks. The later periods were characterized by increasing membranous osteogenesis in and around the granules leading to the formation of bone-like structures showing periosteal and tendon-like structures with bone marrow and focal chondrogenesis. Bone formation was better in the subcutaneous than in the intramuscular implantation sites. This ectopic osteogenesis is discussed with regard to the nanoporosity and microporosity of the material, physico-chemical interactions at its surface, the differentiation of osteoblasts, the role of angiogenesis and the probable involvement of growth factors. The results of this preliminary study indicate that this biomaterial has osteoinductive potential and induces the formation of bone structures, mainly in subcutaneous adipose tissue in the pig.

Macroscopical, histological, and morphometric studies of porous bone-replacement materials in minipigs 8 months after implantation.

OBJECTIVE: The aim of this investigation was to test the induction of bone formation and biodegradation of different biomaterials based on calcium phosphate (CaP). Up to now, hydroxyapatite and beta-tricalcium phosphate ceramics have routinely been sintered at temperatures of 1300 degrees C. The new CaP biomaterials tested are fabricated by a sol-gel process at only 700 degrees C. STUDY DESIGN: Critical-size defects (>5 cm(3)) in the mandible of 15 adult Goettingen minipigs were filled with 1 of the 2 new types of CaP biomaterials, or with 1 of 2 well-known old-type ceramics, or with a gelatin sponge (in the control group). Macroscopical, histological, and morphometric examination of the former defect areas were made 8 months postoperatively. RESULTS: Eight months after implantation of the new CaP biomaterials, complete bone formation was observed in the defect area, and at the same time, the foreign material was resorbed almost completely. After implantation of the classical types of ceramics, only incomplete bone formation and a lesser resorption rate of the foreign bodies were noted. The difference in the bone formation rate was significant: more than 93% for the new CaP biomaterials versus less than 58% for the classical types of ceramics (P < 0.01). CONCLUSION: The biological behavior of the new CaP biomaterials was better than that of the old-type sintered ceramic bone-grafting materials. These new CaP matrices are suitable for filling bone defects and are of interest for dentists, including implantologists, craniomaxillofacial and orthopedic surgeons, as well as traumatologists.

Veloplasty using the wave-line technique versus classic intravelar veloplasty.

OBJECTIVE: A well-known problem in primary surgery of the soft palate is its shortness and the deficit of local soft tissue. This article introduces a modification of the primary intravelar veloplasty, allowing lengthening of the soft palate, and compares this alternative technique to the classic intravelar veloplasty. METHOD: The soft palate wave-line technique adds a wavy incision at the velar cleft margins to the intravelar veloplasty. In 24 patients with complete clefts of the palate, either the newly developed or classic technique was performed. Four years following primary surgery, speech performance and type of breathing were analyzed. RESULTS: Even in wide clefts of the soft palate, repair was easily accomplished using the wave-line technique. Complete closure of the nasal, muscular, and oral layers was achieved, and no postoperative fistula was observed. An average lengthening of the soft palate of 56% (range 24% to 83%) was observed immediately following velar repair with the wave-line technique. Speech was significantly better in the wave-line group (p <.05). Furthermore, physiological breathing was observed more often in these patients. CONCLUSION: Primary repair of clefts of the soft palate using the wave-line technique is straightforward, safe, and easy. On the basis of the present results, this technique seems superior to the classic intravelar veloplasty.