Comparison of an Er: YAG laser osteotome versus a conventional drill for the use in osteo- odonto-keratoprosthesis (OOKP).

OBJECTIVES: The osteo-odonto-kerato-prosthesis (OOKP) procedure is a complex, multi-stage, multidisciplinary surgical intervention for the treatment of severe corneal blindness. One step of the OOKP consists of creating a precise hole into a tooth in which an optic cylinder is subsequently inserted; its shape must ensure a perfect watertight fit. The Er: YAG laser (L) used in this study is part of CARLO®, the first laser osteotome that enables surgical planning based on computed tomography data, robot guidance, and a precise execution of laser cuts in teeth and bone tissue, using laser photoablation rather than conventional mechanical methods. The purpose of this study was to assess whether the Er: YAG laser is non-inferior compared to a conventional drill. METHODS: Thirty-two bovine incisors were grounded to a thickness of 1.5 mm. In 16 teeth, a 3.5 mm hole was drilled progressively into each tooth, using dental burs (B) of increasing diameter that were attached to a fixed drill machine. In the other 16 teeth, a hole was created using an Er: YAG laser at a wavelength of 2.94 µm (Part of CARLO®). In seven teeth of each group, the cylinder was inserted and fixated with polymethylmethacrylate (PMMA) bone cement. In the remaining seven teeth of each group, the cylinder was inserted without fixation material (press-fit). After bonding and drying, all specimens were stored in water until force measurements were recorded using a uniaxial traction machine. The force required to move the optical cylinder out of the hole in the tooth was measured using an Instron 3344 testing system. Scanning electron microscope (SEM) and light microscope (LM) visualization of the holes created with the laser and the drill were performed in two teeth (SEM)/four teeth (LM) per method. RESULTS: Significant differences (P < 0.001) were found for the following parameters: B PMMA versus B press-fit; B PMMA versus L press-fit; L PMMA versus B press-fit; L PMMA-L press-fit. This shows that PMMA bone cement fixation is superior to press-fit. No significant differences were found between B PMMA-L PMMA (P = 0.93) and B press-fit-L press-fit (P = 0.83). The SEM pictures showed a smoother surface using L. CONCLUSIONS: The laser cut holes were as strong as bur-drilled holes, although SEM pictures showed a smoother surface of the laser cut holes. Hence, laser osteotomes open the possibility to custom fit the hole exactly to the width of the cylinder, which represents a potential advantage of the laser over the conventional bur. Lasers Surg. Med. 51:531-537, 2019. © 2019 Wiley Periodicals, Inc.

Traumatic ulcerative granuloma with stromal eosinophilia - clinical case report, literature review, and differential diagnosis.

BACKGROUND: Traumatic ulcerative granuloma with stromal eosinophilia (TUGSE) is a rare self-limiting condition of the oral mucosa. The lesion manifests as an isolated ulcer that can be either asymptomatic or associated with mild to severe pain, and in most cases, it affects the tongue. TUGSE lesions may mimic malignancy such as squamous cell carcinoma, CD30 positive lymphoproliferative disorder, or infectious diseases such as primary syphilis, tuberculosis, or Epstein-Barr virus mucocutaneous ulcer. Histologically dominating cells are lymphocytes, histiocytes, and eosinophils. CASE PRESENTATION: We describe a TUGSE case of a patient with a solitary ulcer on the lower left retromolar buccal plane. Upon presentation, the patient reported a swelling on the buccal mucosa of the left lower jaw since 1 year with rapid growth over the last days and mild pain while chewing. The diameter of the intraoral lesion on the lower left retromolar buccal plane was approximately 4 × 3 cm; the lesion presented as indurated base with a central superficial ulceration of 2 × 1 cm, indicative for a malignant process. Histologically, the ulceration showed an expanding, infiltrative, and vaguely granulomatous morphology, involving the superficial mucosa and the fatty tissue, and extended between the deep striated muscle fibers. The lesion was rich in lymphocytes, histiocytes, and eosionophils intermingled with activated T-blasts without phenotypic abnormalities. TUGSE was then diagnosed based on the phenotype (especially the lacking expression of CD30, the retained T-cell phenotype, and the absence of Epstein-Barr virus), the clinical presentation, and the morphology. Twenty-six months after diagnosis, no recurrence of the ulceration was seen. CONCLUSIONS: As TUGSE may mimic malignancy or infectious diseases, biopsy is mandatory and should be combined with thorough clinical examination. A screening for infectious diseases (mainly syphilis, Epstein-Barr virus, and HIV infections) must be performed routinely. In most cases, the lesions resolve spontaneously, obviating the need of further actions other than clinical follow-up. The pathogenesis of TUGSE lesions is still under debate, although local traumatic events and a locotypic immune response have been suggested to be major contributing factors.

Comparison of Artificial Intelligence-Based Applications for Mandible Segmentation: From Established Platforms to In-House-Developed Software.

Medical image segmentation, whether semi-automatically or manually, is labor-intensive, subjective, and needs specialized personnel. The fully automated segmentation process recently gained importance due to its better design and understanding of CNNs. Considering this, we decided to develop our in-house segmentation software and compare it to the systems of established companies, an inexperienced user, and an expert as ground truth. The companies included in the study have a cloud-based option that performs accurately in clinical routine (dice similarity coefficient of 0.912 to 0.949) with an average segmentation time ranging from 3'54″ to 85'54″. Our in-house model achieved an accuracy of 94.24% compared to the best-performing software and had the shortest mean segmentation time of 2'03″. During the study, developing in-house segmentation software gave us a glimpse into the strenuous work that companies face when offering clinically relevant solutions. All the problems encountered were discussed with the companies and solved, so both parties benefited from this experience. In doing so, we demonstrated that fully automated segmentation needs further research and collaboration between academics and the private sector to achieve full acceptance in clinical routines.

Fibula Graft Cutting Devices: Are 3D-Printed Cutting Guides More Precise than a Universal, Reusable Osteotomy Jig?

Individual cutting guides for the reconstruction of lower jaw defects with fibular grafts are often used. However, the application of these osteotomy tools is costly and time intensive. The aim of this study was to compare the precision of osteotomies using a 3D-printed guide with those using a universal, reusable, and more cost-efficient Multi-Use Cutting Jig (MUC-Jig). In this non-blinded experimental study, 10 cranio-maxillofacial surgeons performed four graft removals each in a randomized order using the same osteotomy angle, both proximally (sagittal cut) and distally (coronal cut), of a graft (45°, 30°, 15°, or 0°), first with the MUC-Jig then with the 3D-printed cutting guide. The 40 fibula transplants (Tx) of each method (n = 80) were then analyzed concerning their Tx length and osteotomy angles and compared to the original planning data. Furthermore, the surgeons' subjective perception and the duration of the two procedures were analyzed. The mean relative length and mean relative angle deviation between the MUC-Jig (-0.08 ± 1.12 mm; -0.69° ± 3.15°) and the template (0.22 ± 0.90 mm; 0.36° ± 2.56°) group differed significantly (p = 0.002; p = < 0.001), but the absolute deviations did not (p = 0.206; p = 0.980). Consequently, clinically comparable osteotomy results can be achieved with both methods, but from an economic point of view the MUC-Jig is a more cost-efficient solution.

In Vitro Mechanical and Biological Properties of 3D Printed Polymer Composite and ß-Tricalcium Phosphate Scaffold on Human Dental Pulp Stem Cells.

3D printed biomaterials have been extensively investigated and developed in the field of bone regeneration related to clinical issues. However, specific applications of 3D printed biomaterials in different dental areas have seldom been reported. In this study, we aimed to and successfully fabricated 3D poly (lactic-co-glycolic acid)/ß-tricalcium phosphate (3D-PLGA/TCP) and 3D ß-tricalcium phosphate (3D-TCP) scaffolds using two relatively distinct 3D printing (3DP) technologies. Conjunctively, we compared and investigated mechanical and biological responses on human dental pulp stem cells (hDPSCs). Physicochemical properties of the scaffolds, including pore structure, chemical elements, and compression modulus, were characterized. hDPSCs were cultured on scaffolds for subsequent investigations of biocompatibility and osteoconductivity. Our findings indicate that 3D printed PLGA/TCP and ß-tricalcium phosphate (ß-TCP) scaffolds possessed a highly interconnected and porous structure. 3D-TCP scaffolds exhibited better compressive strength than 3D-PLGA/TCP scaffolds, while the 3D-PLGA/TCP scaffolds revealed a flexible mechanical performance. The introduction of 3D structure and ß-TCP components increased the adhesion and proliferation of hDPSCs and promoted osteogenic differentiation. In conclusion, 3D-PLGA/TCP and 3D-TCP scaffolds, with the incorporation of hDPSCs as a personalized restoration approach, has a prospective potential to repair minor and critical bone defects in oral and maxillofacial surgery, respectively.

Piezoelectric harvesting of an autogenous bone graft from the zygomaticomaxillary region: case report.

The zygomaticomaxillary region offers a large amount of cortical bone that can be obtained simply and safely using the precise and selective cutting properties of a piezosurgical device. A block from this area fits nicely into anterior or premolar maxillary recipient sites and is thus the ideal choice, as no secondary surgical field is needed. As in conventional sinus bone graft procedures, the complication rate is minimal and after a 5-month healing period, the augmented region can be used for stable and esthetic oral implant placement.

Callus mineralization following distraction osteogenesis of the mandible monitored by scanning acoustic microscopy (SAM).

BACKGROUND: Scanning acoustic microscopy uses ultrasound to analyse histomorphology of tissues with microscopic resolution and delivers data about physical properties of the specimen. MATERIAL AND METHODS: Bony consolidation was monitored by scanning acoustic microscopy in 12 embedded specimens of dog mandibles after distraction osteogenesis. Increasing mineralization was detected by measurements of acoustic impedance (Z). RESULTS: There was a strong correlation between acoustic impedance and time of consolidation. Measurements of the speed of sound (v) provided specific information about non-mineralized zones of the distracted area. Distribution of density in the distracted area could be reconstructed by using the measurements of acoustic impedance and speed of sound. CONCLUSION: The method seems suitable for studying bone remodelling qualitatively and quantitatively.

Possible problems of moulding the regenerate in mandibular distraction osteogenesis -- experimental aspects in a canine model.

INTRODUCTION: Moulding of the regenerate created by distraction osteogenesis has been shown clinically to be efficient and good enough so that for complex three-dimensional deformities, final adjustments by moulding the regenerate may be part of the treatment plan. This study assessed possible drawbacks of moulding a regenerate, taking into consideration compressive and tensile forces acting simultaneously on the fresh callus. METHOD: Distraction osteogenesis in 15 Beagle mandibles was performed using custom made devices which allowed for lengthening as well as for angulation. After linear distraction of 10 mm, a defined 20 degrees angulation was performed in one step. The position of the fulcrum of the device allowed simultaneously compression and stretching of the regenerated bone. Effects on bone healing were assessed after 6 and 13 weeks of consolidation respectively and compared with a control group where only linear distraction was performed. RESULTS: Radiological and histological investigations demonstrated that no significant differences between the biological behaviour of the compressed and the stretched zones of the regenerate could be found. However, there were signs showing the more critical character of the stretched area. After 6 weeks of consolidation some specimens revealed delayed ossification of the stretched zone. Under stable conditions, this delay was compensated for after 13 weeks of consolidation and complete osseous healing occurred. CONCLUSION: Under stable conditions, a fresh regenerate can be moulded to a considerable extent without permanently endangering osseous healing. Nevertheless tensile forces acting on the regenerate should be minimized to prevent damage to the new bone. This can be achieved by overdistraction prior to callus moulding or by gradually changing the vector of distraction during the lengthening process.

Intraorbital abscess: a rare complication after maxillary molar extraction.

BACKGROUND: The orbit is prone to being affected by an odontogenous infection, owing to its anatomical proximity to the maxillary sinus. A possible reason for an ophthalmic manifestation of a dental abscess is extraction of an acutely inflamed tooth. CASE DESCRIPTION: The authors describe the treatment of a man who had painful swelling and redness in the area of his right eye after having a maxillary molar extracted a few days previous. A general dentist referred the patient to the clinic after he began to experience a progressive deterioration of vision of his right eye. Emergency surgical intervention prevented impending loss of vision, and subsequent healing was uneventful. CLINICAL IMPLICATIONS: To avoid serious complications, clinicians should not perform a tooth extraction when the patient is in the acute stage of a maxillary sinus infection. Appropriate diagnostic imaging and profound evaluation of the clinical state play major roles in managing the treatment of patients with inflammatory processes that involve the oral and paraoral regions.

Cone-beam computed tomography for planning and assessing surgical outcomes of osteo-odonto-keratoprosthesis.

PURPOSE: The aim of this study was to investigate the feasibility and effectiveness of cone-beam computed tomography (CBCT) in the planning, assessment, and follow-up for osteo-odonto-keratoprosthesis (OOKP). METHODS: Six OOKP patients received a CBCT scan. CBCT scans were performed before and/or between ∼5 and 504 months after the primary OOKP intervention. Preoperative and postoperative results of the CBCT were assessed, regarding the available teeth and to assess the loss of bone in 1 patient, respectively. Resorption of the osteo-odonto-lamina was measured and graded. Five different measurements (I-V) were performed in the coronal and transversal views of CBCT. RESULTS: Four CBCT scans were performed preoperatively and 4 postoperatively. The follow-up time of the patients is between ∼1 to 528 months. Visualization of the potential donor teeth resulted in accurate 3-dimensional visualization of the tooth-lamina-bone complex. CBCT was found to help in the preoperative decision-making process (diameter of optical implant) and in enabling accurate postoperative evaluation of the bone volume and resorption zones of the OOKP. Loss of bone could be measured in a precise range and showed in the completed cases an average loss of 20.2%. CONCLUSIONS: The use of CBCT simplifies the preoperative decision making and ordering process. It also helps in determining the postoperative structure and resorption of the prosthesis.

Maxillofacial reconstruction with prefabricated osseous free flaps: a 3-year experience with 24 patients.

Between January of 1998 and May of 2002, 25 prefabricated osseous free flaps (23 fibula and two iliac crest flaps) were transferred in 24 patients to repair maxillary (six flaps) or mandibular (eight flaps) defects after tumor resection, severe maxillary (four flaps) or mandibular (one flap) atrophy (Cawood VI), maxillary (one flap) or mandibular (three flaps) defects after gunshot injury, and maxillary (two flaps) defects after traffic accidents. Prefabrication included insertion of dental implants, positioned with a drilling template in a preplanned position, and split-thickness grafting. Drilling template construction was based on the prosthetic planning. The template determined the position of the implants and the site and angulation of osteotomies, if necessary. The mean delay between prefabrication and flap transfer was 6 weeks (range, 4 to 8 weeks). While the flap was harvested, a bar construction with overdentures was mounted onto the implants. The overdentures were used as an occlusal key for exact three-dimensional positioning of the graft within the defect. The bar construction also helped to stabilize the horseshoe shape of the graft. The follow-up period ranged from 2 months to 4 years (mean, 21 months), during which time two total and three partial flap losses occurred. One total loss was due to thrombosis of the flap veins during the delay period, whereas the other total loss was caused by spasm of the peroneal artery. Two partial losses were due to oversegmentation of the flaps with necrosis of the distal fragment, whereas one partial loss was caused by disruption of the vessel from the distal part. Of the 90 implants that were inserted into the prefabricated flaps during the study period, 10 were lost in conjunction with flap failure; of the remaining 80 implants, four were lost during the observation period, for a success rate of 95 percent. Flap prefabrication based on prosthetic planning offers a powerful tool for various reconstructive problems in the maxillofacial area. Although it involves a two-stage procedure, the time for complete rehabilitation is shorter than with conventional procedures.

The Comprehensive AOCMF Classification System: Midface Fractures - Level 3 Tutorial.

This tutorial outlines the details of the AOCMF image-based classification system for fractures of the midface at the precision level 3. The topography of the different midface regions (central midface-upper central midface, intermediate central midface, lower central midface-incorporating the naso-orbito-ethmoid region; lateral midface-zygoma and zygomatic arch, palate) is subdivided in much greater detail than in level 2 going beyond the Le Fort fracture types and its analogs. The level 3 midface classification system is presented along with guidelines to precisely delineate the fracture patterns in these specific subregions. It is easy to plot common fracture entities, such as nasal and naso-orbito-ethmoid, and their variants due to the refined structural layout of the subregions. As a key attribute, this focused approach permits to document the occurrence of fragmentation (i.e., single vs. multiple fracture lines), displacement, and bone loss. Moreover, the preinjury dental state and the degree of alveolar atrophy in edentulous maxillary regions can be recorded. On the basis of these individual features, tooth injuries, periodontal trauma, and fracture involvement of the alveolar process can be assessed. Coding rules are given to set up a distinctive formula for typical midface fractures and their combinations. The instructions and illustrations are elucidated by a series of radiographic imaging examples. A critical appraisal of the design of this level 3 midface classification is made.

The Comprehensive AOCMF Classification System: Classification and Documentation within AOCOIAC Software.

The AOCMF Classification Group developed a hierarchical three-level craniomaxillofacial (CMF) fracture classification system. The fundamental level 1 distinguishes four major anatomical units including the mandible (code 91), midface (code 92), skull base (code 93) and cranial vault (code 94); level 2 relates to the location of the fractures within defined topographical regions within each units; level 3 relates to fracture morphology in these regions regarding fragmentation, displacement, and bone defects, as well as the involvement of specific anatomical structures. The resulting CMF classification system has been implemented into AO comprehensive injury automatic classifier (AOCOIAC) software allowing for fracture classification as well as clinical documentation of individual cases including a selected sample of diagnostic images. This tutorial highlights the main features of the software. In addition, a series of illustrative case examples is made available electronically for viewing and editing.

The Comprehensive AOCMF Classification System: Radiological Issues and Systematic Approach.

The AOCMF Classification Group developed a hierarchical three-level craniomaxillofacial (CMF) classification system with increasing level of complexity and details. The basic level 1 system differentiates fracture location in the mandible (code 91), midface (code 92), skull base (code 93), and cranial vault (code 94); the levels 2 and 3 focus on defining fracture location and morphology within more detailed regions and subregions. Correct imaging acquisition, systematic analysis, and interpretation according to the anatomic and surgical relevant structures in the CMF regions are essential for an accurate, reproducible, and comprehensive diagnosis of CMF fractures using that system. Basic principles for radiographic diagnosis are based on conventional plain films, multidetector computed tomography, and magnetic resonance imaging. In this tutorial, the radiological issues according to each level of the classification are described.

The Comprehensive AOCMF Classification System: Fracture Case Collection, Diagnostic Imaging Work Up, AOCOIAC Iconography and Coding.

The AO classification system for fractures in the adult craniomaxillofacial (CMF) skeleton is organized in anatomic modules in a 3 precision-level hierarchy with account for an increasing complexity and details. Level-1 is most elementary and identifies no more than the presence of fractures in 4 separate anatomical units: the mandible (code 91), midface (92), skull base (93) and cranial vault (94). Level-2 relates the detailed topographic location of the fractures within defined regions of the mandible, central and lateral midface, internal orbit, endo- and exocranial skull base, and the cranial vault. Level-3 is based on an even more refined topographic assessment and focuses on the morphology - fragmentation, displacement, and bone defects - within specified subregions. An electronic fracture case collection complements the preceding tutorial papers, which explain the features and options of the AOCMF classification system in this issue of the Journal. The electronic case collection demonstrates a range of representative osseous CMF injuries on the basis of diagnostic images, narrative descriptions of the fracture diagnosis and their classification using the icons for illustration and coding of a dedicated software AOCOIAC (AO Comprehensive Injury Automatic Classifier). Ninety four case examples are listed in two tables for a fast overview of the electronic content. Each case can serve as a guide to getting started with the new AOCMF classification system using AOCOIAC software and to employ it in the own clinical practice.

The Comprehensive AOCMF Classification System: Mandible Fractures- Level 2 Tutorial.

This tutorial outlines the details of the AOCMF image-based classification system for fractures of the mandible at the precision level 2 allowing description of their topographical distribution. A short introduction about the anatomy is made. Mandibular fractures are classified by the anatomic regions involved. For this purpose, the mandible is delineated into an array of nine regions identified by letters: the symphysis/parasymphysis region anteriorly, two body regions on each lateral side, combined angle and ascending ramus regions, and finally the condylar and coronoid processes. A precise definition of the demarcation lines between these regions is given for the unambiguous allocation of fractures. Four transition zones allow an accurate topographic assignment if fractures end up in or run across the borders of anatomic regions. These zones are defined between angle/ramus and body, and between body and symphysis/parasymphysis. A fracture is classified as "confined" as long as it is located within a region, in contrast to a fracture being "nonconfined" when it extents to an adjoining region. Illustrations and case examples of mandible fractures are presented to become familiar with the classification procedure in daily routine.

The Comprehensive AOCMF Classification System: Midface Fractures - Level 2 Tutorial.

The AOCMF Classification Group developed a hierarchical three-level craniomaxillofacial classification system with increasing level of complexity and details. The highest level 1 system distinguish four major anatomical units including the mandible (code 91), midface (code 92), skull base (code 93), and cranial vault (code 94). This tutorial presents the level 2 system for the midface unit that concentrates on the location of the fractures within defined regions in the central (upper, intermediate, and lower) and lateral (zygoma, pterygoid) midface, as well as the internal orbit and palate. The level 2 midface fracture location outlines the topographic boundaries of the anatomical regions. The common nasoorbitoethmoidal and zygoma en bloc fracture patterns, as well as the time-honored Le Fort classification are taken into account. This tutorial is organized in a sequence of sections dealing with the description of the classification system with illustrations of the topographical cranial midface regions along with rules for fracture location and coding, a series of case examples with clinical imaging and a general discussion on the design of this classification. Individual fracture mapping in these regions regarding severity, fragmentation, displacement of the fragment or bone defect is addressed in a more detailed level 3 system in the subsequent articles.

The Comprehensive AOCMF Classification System: Mandible Fractures-Level 3 Tutorial.

This tutorial outlines the details of the AOCMF image-based classification system for fractures of the mandibular arch (i.e. the non-condylar mandible) at the precision level 3. It is the logical expansion of the fracture allocation to topographic mandibular sites outlined in level 2, and is based on three-dimensional (3D) imaging techniques/computed tomography (CT)/cone beam CT). Level 3 allows an anatomical description of the individual conditions of the mandibular arch such as the preinjury dental state and the degree of alveolar atrophy. Trauma sequelae are then addressed: (1) tooth injuries and periodontal trauma, (2) fracture involvement of the alveolar process, (3) the degree of fracture fragmentation in three categories (none, minor, and major), and (4) the presence of bone loss. The grading of fragmentation needs a 3D evaluation of the fracture area, allowing visualization of the outer and inner mandibular cortices. To document these fracture features beyond topography the alphanumeric codes are supplied with distinctive appendices. This level 3 tutorial is accompanied by a brief survey of the peculiarities of the edentulous atrophic mandible. Illustrations and a few case examples serve as instruction and reference to improve the understanding and application of the presented features.

[Not Available]. / Der Zahn im Auge - Die erste in der Schweiz eingebrachte Osteo-Odonto-Keratoprothese.

We report on the first implanted Osteo-Odonto-Keratoprosthesis (OOKP) in Switzerland. The procedure is only performed in cases of severe bilateral corneal vision impairment without alternatives (e. g. allogenic corneal transplant). At this two-staged surgery a single-rooted tooth is removed with its belonging bone and an optic cylinder is centrally inserted. This tooth-bone-optic-cylinder-complex is implanted temporarily submuscular in the infraorbital area. Oral mucosa is removed and transplanted on to the eye. Three months later the complex is removed, the oral mucosa partially detached, the underlying cornea perforated, the lens, iris and anterior vitreous body removed and the tooth-optic-zylinder-complex fixated on the globe. After this procedure, our patient has a best corrected visual acuity of 0,7.