Exceptional Cases Demand Exceptional Personalized Solutions: The Next Level in Dental Rehabilitation.

Defects and bone loss in the maxilla and mandible pose significant challenges for dental rehabilitation. This paper focuses on complex cases of bimaxillary dental rehabilitation, where traditional dental implant protocols were not feasible in at least one jaw. Four patients were examined conceptually, where conventional dental implant placement (n = 20) was combined in either the same or opposite jaw with a patient-specific subperiosteal implant (n = 5). This study evaluates aspects such as primary stability, prosthodontic restoration, complications, and soft tissue management over the observation period. None of the five patient-specific subperiosteal implants (IPS Implants® Preprosthetic; KLS-Martin Group, Tuttlingen, Germany) experienced failure or showed any loosening of screws, with the longest observation period extending to 68 months. These implants were securely fixated away from the posts, without any biomechanical restrictions on loading from the time of insertion. Planning and manufacturing, including the initial suprastructure, followed a fully digital workflow. The number of screws required for multivector fixation ranged from 13 to 22. All dental implants placed remain functional, definitive prosthodontic restoration has been performed, and no stability loss or peri-implantitis has been observed. The IPS Implants® Preprosthetic emerges as a valuable consideration when conventional implant dentistry protocols encounter limitations.

Dental rehabilitation in irradiated oral cancer patients using patient-specific dental implants - Clinical outcome and oral health-related quality of life.

INTRODUCTION: Dental rehabilitation in oral cancer patients is essential for good oral health-related quality of life (OHRQoL). Patient-specific dental implants are suitable for treating tumor-related bony defects, resulting in satisfactory OHRQoL. However, knowledge concerning the clinical outcome and OHRQoL following tumor irradiation is lacking. MATERIAL AND METHODS: A retrospective analysis was carried out to evaluate clinical outcomes and OHRQoL in eight patients who received patient-specific dental implants and implant-supported dentures after surgical treatment for oral cancer with additional irradiation. OHRQoL assessment was performed using the German long version of the oral health impact profile (OHIP) questionnaire (OHIP-G53). RESULTS: Clinical examination revealed successful dental rehabilitation in all the patients with only minor impairments. Restricted stability and function of implants were not observed. OHIP sum-scores of all the patients indicated acceptable OHRQoL, but this varied between patients treated in the upper or lower jaw. Single-item sum-scores concerning the adverse events "difficulty in chewing," "food catching," "sore jaw," "sore spots," and "unclear speech" were detected to be the worst, and pain-related OHIP dimensions demonstrated the highest scores (followed by functional limitation, physical disability, and psychosocial impact) with a worse OHRQoL following lower jaw treatment. Other dimension sum-scores were overall lower and nearly equally distributed in patients. CONCLUSIONS: Dental rehabilitation of irradiated oral cancer patients using patient-specific dental implants may be suitable, leading to acceptable OHRQoL. However, implant insertion in the upper jaw seems to be more favorable. Further studies on patient-specific dental implants are warranted to validate the current results.

Computer-assisted orbital and midfacial reconstruction.

Objective: Computer assistance has become indispensable in the reconstruction of the orbit and midface. Although these are key areas of an individual's esthetic appearance, defects or deformities of the midface, especially those of the orbit, are treated diversely. Methods: The aim of this article is to present the wide utility of computer-assistance in modern craniomaxillofacial surgery, including virtual planning, computer-aided design, guided surgery, navigational control, patient-specific implants, and quality control via image fusion. Results: There have been rapid advances in both digital planning and manufacturing processes, with continual improvements. Conclusions: Patient-specific implants have pushed the boundaries of reconstructive surgery in all surgical specialties.

Comparing Original and Universal Screwdrivers and How They Affect Friction in the Screw.

The present study focused on investigating whether universal screwdriver kits cause less friction between the screwdriver and the abutment screw than original screwdrivers. For this purpose, 2 original screwdrivers (Straumann and BEGO) and a universal screwdriver kit (bredent) were investigated. On 1 implant per screwdriver, 26 abutments were properly attached one after the other with the corresponding abutment screws. After tightening the abutment screw, the force required to pull the screwdriver off the screw head was determined with a spring balance. For both manufacturers, greater pull-off forces were measured when using the original screwdrivers than when using the universal screwdriver. The pull-off force (mean ± SD) required for the Straumann original screwdriver was 3.7 ± 1.4 N, while that required for the universal screwdriver was 0.1 ± 0.1 N (P < .001). The pull-off force was 1.5 ± 1.5 N for the BEGO original screwdriver and 0.7 ± 0.9 N for the universal screwdriver (P = .19). Using original manufacturer-supplied screwdrivers could thus minimize the risk of the screwdriver slipping out of the screw head during dental treatment and being swallowed or aspirated by the patient.

Time is crucial in malignant tumor cases: Speeding up the process of patient-specific implant creation.

Purpose: Patient-specific implants are commonly used to reconstruct lower jaw defects following surgical treatment for head and neck squamous cell carcinoma. The planning process of surgery is time-consuming and can delay the "time to surgery," which should be as short as possible. Therefore, this study aimed to evaluate the planning process to speed up and identify any sources of problems. Patients and methods: In this retrospective study, we enrolled patients who underwent continuous resection of the mandible in combination with reconstruction with a patient-specific implant between 2016 and 2021. The predictor variables were in-house training of the engineers and implant complexity (complex [with additional features] vs. less complex [resembling standard reconstruction plates]). The outcome variables were the duration of communication, message length, and the need for synchronous communication or modifications to the original design. Descriptive and univariate statistics were computed, and statistical significance was set at P < 0.05. Results: The data from 83 patients were included in this study. The mean duration of communication was 14.05 ± 13.58 days. The implant complexity and training status of the engineer had no statistically significant influence on the primary outcome variables. As for the secondary outcome variables, the implant complexity significantly influenced the chance that the planned operation had to be postponed (15/16 [93.75%] were complex cases, P = 0.001). The most frequent cause of problems in the planning process was an insufficient dataset, which was not dependent on the type of imaging. Conclusions: The overall duration of the patient-specific implant creation process is too long to meet oncological requirements. Therefore, standardization of the planning process to accelerate implant creation is of utmost importance. In addition, a common standard imaging format (independent of the type of imaging) for oncological cases could eliminate all delays caused by insufficient datasets in the future.

Outcome and Quality of Life after Individual Computer-AssistedReconstruction of the Midface. / Ergebnisse und Lebensqualität nach individueller computer-gestützter Rekonstruktion des Mittelgesichtes.

Often, midfacial defects are not only relevant regarding functional aspects but also esthetics of such congenital or acquired deformities impair significantly the patients' quality of life. Reconstructions of the midface do not only include replacing lost or non-developed tissue but moreover to achieve predictable results with regard to esthetics as well as function for the individual patient. Digital planning modalities including different surface and volume data in combination with modern additive manufacturing techniques for biomodel and implant production and intraoperative support by using real and virtual 3D volume data for navigation and intraoperative imaging, but also securing the outcome based on postoperative analysis have been implemented in modern midface reconstruction and represent new standards for medical care. The objective of this paper is to describe modern options of patient-specific midfacial reconstruction with integration of computer-assisted planning and production techniques.

Novel approach for treating challenging implant-borne maxillary dental rehabilitation cases of cleft lip and palate: a retrospective study.

PURPOSE: Dental restoration in cleft lip and palate (CLP) patients is demanding and often results in bone loss and dental implant failure. Furthermore, unfavorable conditions of hard and soft tissues as well as skeletal deformities aggravate surgical and dental treatment. Therefore, this study was designed to assess the feasibility of using a new type of patient-specific implant (IPS-preprosthetic®) in CLP patients. METHODS: Of the 63 patients who received a IPS-preprosthetic® implant in the Department of Oral and Maxillofacial Surgery at the Hannover Medical School, Germany, six patients were treated for a CLP deformity with significant soft and hard tissue impairment. Two patients were partially edentulous, whereas four patients were edentulous for the maxilla. All implants were inserted in a single-step outpatient surgery and were followed up for up to 40 months. RESULTS: Within the observation period, no implant failed and no screw loosening or change in stability of the implant to recipient site occurred (mean number of screws: 21). This study demonstrates, for the first time, the efficient use of a one-piece multivector screw primarily retained a stable patient-specific implant for implant-borne prosthodontic rehabilitation of CLP patients with deformities and challenging initial situations. CONCLUSIONS: IPS-preprosthetic® implants offer a novel approach to implant dentistry treatment protocols, especially in difficult cases of unusual anatomy, even when previous conventional treatment fails.

Comparison of conventional and digital workflow for dental rehabilitation with a novel patient-specific framework implant system: an experimental dataset evaluation.

PURPOSE: This study aimed to evaluate the efficiency of a digital workflow by comparing the accuracy of prosthetic teeth positioning between virtual standard-size digitally constructed and conventional dental laboratory-fabricated prostheses. METHODS: Twenty-five computed tomography datasets with a dentate upper jaw were selected after applying inclusion criteria to 100 random datasets obtained from the institutional library, and partially edentulous maxillae were constructed virtually. Digital datasets of temporary prostheses were fabricated on these virtually constructed edentulous maxillae in two ways: one dataset comprised prostheses that were fabricated conventionally using prosthetic teeth and wax in the dental laboratory and then scanned using a model scanner, whereas the other dataset was designed virtually using standardized virtual dental arches. The digital datasets of both prostheses were compared for differences at six dental-based measurement points with the original patient dentition. RESULTS: Overall, the conventional design pathway was more accurate than the digital one (conventional 2.915 ± 1.388 mm, digital 3.609 ± 2.052 mm, P < 0.001). However, when all six measurement points were evaluated individually, only three points showed significant differences in the tooth positions. Compared with the original dentition, the deviations were less in the anterior teeth region than in the molar region, fulfilling the esthetic expectations of the patients. Standardized virtual dental arches were practically adequate because virtual reconstruction of every edentulous case using these virtual arches was possible without any additional modifications. CONCLUSION: It is possible to fabricate clinically acceptable temporary prostheses using a comprehensive digital workflow based on standardized digital dental arches.

Referencing for intraoperative navigation: Evaluation of human bias.

Navigation-assisted surgery is the gold standard for complex reconstructive procedures of the midface and facial skeleton, and artificial and anatomical landmarks are often used for reference. The correct identification of these landmarks before surgery is crucial for the accuracy of the navigation system. This study aimed to investigate the human errors in reference point placement. This retrospective study investigated 228 reference-point positions in 51 cases where navigation was utilized. The discrepancies between the actual reference point-position and manually planned preoperative reference points were quantified using Brainlab iPlanCMF 3.0.6. The referencing methods used in these cases included dental registration splints, osteosynthesis materials, anatomical landmarks, and combinations of these methods. The average discrepancy in the actual and manually planned reference points was 0.29 ± 0.41 mm. The use of anatomical landmarks demonstrated a significantly lower deviation (p < 0.05), although the differences between the errors in reference-point placement using dental registration splints, osteosynthesis materials, or combinations of these methods were not statistically significant. The frequency of misplacement of reference points was significantly higher than expected. These errors might have been caused by human bias during manual placement of the points or intraoperative difficulties caused by extensive metal artifacts. Thus, we postulate that the surgical personnel involved in planning navigation-assisted surgery should undergo intensive training. The development of new referencing methods that are less susceptible to these causes of error might help overcome human bias.

Managing the severely atrophic maxilla: Farewell to zygomatic implants and extensive augmentations?

BACKGROUND: Dental rehabilitation of severe atrophic upper jaws remains challenging. A new generation of subperiosteally placed and rigid multi-vector bone-anchored patient-specific implants proposes an innovative line extension in implant dentistry. This single-center retrospective study focused on treating severely atrophic maxillae using these implants. METHODS: All patients who were treated with a patient-specific implant (IPS Implant® Preprosthetic, KLS-Martin, Tuttlingen, Germany) at Hannover Medical School due to severe atrophy of the maxilla who had no history of malignancy, cleft lip or palate, or trauma were evaluated regarding implant stability and prosthetic restoration, as well as complications. RESULTS: Out of a total of 58 inserted implants, 13 implants in 10 patients, which were placed to treat a severely atrophic upper jaw, were identified. The mean follow-up period was 8.2 months (1-29 months). All implants were clinically stable over the entire period. All patients with an observation period of over 2 months received prosthetics for restoration. Minor complications, screw fractures, infection, and exposure of the framework were observed, but these did not lead to failure. CONCLUSION: This initial follow-up suggests that this new generation of implants represents a valuable treatment alternative, especially for patients with a history of failed dental implant placement. Larger numbers of cases and longer observation periods are required to confirm our findings.

A New Strategy for Patient-Specific Implant-Borne Dental Rehabilitation in Patients With Extended Maxillary Defects.

PURPOSE OF THE STUDY: Patients undergoing ablative tumor surgery of the midface are faced with functional and esthetic issues. Various reconstructive strategies, such as implant-borne obturator prostheses or microvascular tissue transfer, are currently available for dental rehabilitation. The present study shows the first follow-up of patients treated with patient-specific implants (IPS Implants® Preprosthetic) for the rehabilitation of extended maxillary defects following ablative surgery. PATIENTS AND METHODS: All patients treated with patient specific implants due to postablative maxillary defects were included. 20 implants were placed in the 19 patients (bilateral implants were placed in one of the cases). In 65.75% of the cases, resection was performed due to squamous cell carcinoma. In addition to the primary stability, the clinical implant stability, soft tissue management, successful prosthodontic restoration, and complications were evaluated at a mean follow-up period of 26 months. RESULTS: All patient-specific implants showed primary stability and were clinically stable throughout the observation period. Definitive prosthodontic restorations were performed in all patients. No implant loosening was observed. Major complications occurred only in previously irradiated patients with insufficient soft tissue conditions (p = 0.058). Minor complications such as exposure of the underlying framework or mucositis were observed, but they never led to failure of restorations or implant loss. CONCLUSIONS: Treatment of postablative maxillary defects with patient-specific implants offers a safe alternative with predictable results for full and rapid dental rehabilitation, avoiding time-consuming augmentation procedures and additional donor-site morbidity.

Changes in Emergency Patient Presentation to a Maxillofacial Surgery Department During the COVID-19 Pandemic.

PURPOSE: To examine possible changes in the emergency patient volume and reasons for presentation to an oral and maxillofacial surgery department during the coronavirus disease 2019 (COVID-19) pandemic and the resulting contact prohibitions. We hypothesized that the pandemic would lead to fewer patients presenting with emergent conditions. METHODS: A total of 939 patients, who presented to the Department for Oral and Maxillofacial Surgery of Hannover Medical School during the first 4 weeks of contact prohibitions in Germany, starting from March 23, 2020 until April 19, 2020, and in comparable periods were examined. The number of patients, reason for presentation, and required treatments were documented and compared to the years 2018 and 2019. Special attention was paid to the changes in trauma cases. RESULTS: We found that the number of patients in 2020 was significantly lower (P(2019) < .001, P(2018) < .01), but sex and age distributions were comparable to those in the previous years. Both the absolute and relative frequencies of dental diagnoses were significantly lower in 2020 (P(2019) < .001, P(2018) < .001), while the proportion of patients who presented with trauma was significantly higher (P(2019) < .001, P(2018) < .001). A significant decrease in patient number to the hospital, despite private practices being closed, was presumably due to patients' infection-related concerns. Trauma cases were more frequent in private settings, and traumatic events under the influence of alcohol were frequent. The circumstances and not the absolute number of trauma events had changed. CONCLUSIONS: The results of this study suggest that the COVID-19 pandemic has important effects on the use of emergency services concerning oral and maxillofacial surgery in Germany.

CAD/CAM-based referencing aids to reduce preoperative radiation exposure for intraoperative navigation.

BACKGROUND: All intraoperative navigation systems need a referencing procedure prior to utilization, usually requiring an additional computed tomography (CT) or cone beam computed tomograph (CBCT) scan. As new techniques in the field of Computer-aided design / Computer-aided manufacturing (CAD/CAM) have evolved, it seemed favourable to develop a new referencing method not relying on additional CT or CBCT scans. METHODS: A digital maxillary dental scan was used to create a referencing splint by CAD/CAM containing four reference points. By matching scanned dental model and initial trauma-CT, the splints position and thus the reference points were digitally simulated. These splints data were imported into the navigation system in Standard Tessellation Language (STL) format. These data were also 3D printed and the resulting piece was placed on the anatomical models' teeth. The methods accuracy was then assessed in vitro. CONCLUSION: Our method for referencing of intraoperative navigation can be feasible to avoid an additional CT or CBCT prior to navigation.

Management of pandemic or large-scale emergencies in Germany with a focus on the current and potential role of university schools of dentistry: Can it help in COVID-19 time?

BACKGROUND: The study presented here systematically examines the potential involvement of dental, oral and maxillofacial centres (ZMK) in the management of pandemia or in large-scale emergencies. It looks at available material and infrastructural resources and how they can be brought to bear in such incidents or situations. The aim was to gain an initial scientific overview of how ZMK can potentially contribute to the handling of a pandemia or mass casualty (MASCAL) situation in terms of available resources as well as their location within the hospital as a whole and their integration into the existing infrastructure. The study was conducted on the basis of a questionnaire consisting of 70 individual questions, which was sent to all universities in Germany that offer a course of study in dental medicine. The responses were then statistically evaluated. RESULTS: The study outlines the current status of ZMK and discusses what could be an important component of emergency medical care in the overall hospital context. CONCLUSION: The involvement of ZMK-with their own resources and existing infrastructural links to the hospital as a whole-could lead to faster and more effective patient treatment in the event of a pandemic or MASCAL situation.

The Impact of Different Augmentative Methods on the Expression of Inflammatory Factors.

Many animal studies show that an intact periosteum plays an important role in osseous regeneration. The potential effect of an in vivo periosteal barrier membrane on the expression of specific proteins has not been examined sufficiently. The aim of the present study is to investigate the influence of the flap preparation method and collagen membrane on the emission of inflammatory factors. This study examines 20 patients with dental implants who had previously undergone an augmentation. A soft tissue sample was taken during augmentation and 3 months later from the same location. Samples were always taken from the margins of a previously prepared mucoperiosteal flap. The flap was raised with a conventional periosteal elevator in the control group and with a piezoelectric device in the test group. In both groups, we covered half of the augmented bone with a native collagen membrane (NCM; Geistlich Bio-Gide). This allowed us to examine the same incision area with and without a membrane. An immunohistochemical analysis was performed for collagen IV, fibronectin, and inflammatory factors such as cluster of differentiation 31 (CD31), cyclooxygenase-2 (COX-2), and interleukin 6 (IL-6). There was a clear difference in the expression of specific proteins after the piezoelectric device and the periosteal elevator were used. The expression of fibronectin, IL-6, and COX-2 was higher after preparation with the periosteal elevator than after piezoelectric periosteum dissection. The expression of collagen IV was higher after the piezoelectric procedure. No difference was observed for CD31. The membrane had no effect on the expression of collagen IV, fibronectin, IL-6, and COX-2. The type of periosteal preparation influences the expression of specific proteins. With regard to the factors examined here, NCM did not appear to influence the wound healing cascade.

Evaluation of accuracy in implant site preparation performed in single- or multi-step drilling procedures.

OBJECTIVES: Dental implant failure and insufficient osseointegration are proven results of mechanical and thermal damage during the surgery process. We herein performed a comparative study of a less invasive single-step drilling preparation protocol and a conventional multiple drilling sequence. Accuracy of drilling holes was precisely analyzed and the influence of different levels of expertise of the handlers and additional use of drill template guidance was evaluated. MATERIAL AND METHODS: Six experimental groups, deployed in an osseous study model, were representing template-guided and freehanded drilling actions in a stepwise drilling procedure in comparison to a single-drill protocol. Each experimental condition was studied by the drilling actions of respectively three persons without surgical knowledge as well as three highly experienced oral surgeons. Drilling actions were performed and diameters were recorded with a precision measuring instrument. RESULTS: Less experienced operators were able to significantly increase the drilling accuracy using a guiding template, especially when multi-step preparations are performed. Improved accuracy without template guidance was observed when experienced operators were executing single-step versus multi-step technique. CONCLUSION: Single-step drilling protocols have shown to produce more accurate results than multi-step procedures. The outcome of any protocol can be further improved by use of guiding templates. Operator experience can be a contributing factor. CLINICAL RELEVANCE: Single-step preparations are less invasive and are promoting osseointegration. Even highly experienced surgeons are achieving higher levels of accuracy by combining this technique with template guidance. Hereby template guidance enables a reduction of hands-on time and side effects during surgery and lead to a more predictable clinical diameter.

Examination of Local Periosteal Microcirculation After Application of Absorbable and Nonabsorbable Membranes.

The use of different membranes is common in dentoalveolar surgery. Absorbable and nonabsorbable membranes are used, often beneath the periosteum, to fulfil different functions (as barriers, patches, or spacers). It is still unclear to what extent such membranes affect the biology of the periosteum and what role is played by piezoelectric devices during preparation of the periosteum. We placed two different membranes (absorbable and nonabsorbable) underneath the periosteum of rat calvaria. We prepared the periosteum using different methods (piezoelectric device vs mechanical device). We then examined and analyzed periosteal microcirculation over a period of 28 days. A clear difference was observed between the two methods when used with absorbable membranes: The piezoelectric device offered advantages. Absorbable membranes maintain considerably more local periosteal microcirculation and should be given preference. In addition, we observed an advantage to using a piezoelectric device for periosteal dissection. Therefore, this method should also be used more widely.

A new concept for implant-borne dental rehabilitation; how to overcome the biological weak-spot of conventional dental implants?

BACKGROUND: Every endosseous dental implant is dependent on an adequate amount and quality of peri-implant hard and soft tissues and their fully functional interaction. The dental implant could fail in cases of insufficient bone and soft tissues or due to a violation of the soft to hard tissues to implant shoulder interface with arising of a secondary bone loss. METHOD: To overcome this biological weak-spot, we designed a new implant that allows for multi vector endosseous anchorage around the individual underlying bone, which has to be scanned by computed tomography (CT) or Cone beam CT (CBCT) technique to allow for planning the implant. We developed a workflow to digitally engineer this customized implant made up of two planning steps. First, the implant posts are designed by prosthodontic-driven backward planning, and a wireframe-style framework is designed on the individual bony surface of the recipient site. Next, the two pieces are digitally fused and manufactured as a single piece implant using the SLM technique (selective laser melting) and titanium-alloy-powder. RESULTS: Preoperative FEM-stress-test of the individual implant is possible before it is inserted sterile in an out-patient procedure. CONCLUSION: Unlike any other historical or current dental implant protocol, our newly developed "individual patient solutions dental" follows the principle of a fully functional and rigid osteosynthesis technology and offers a quick solution for an implant-borne dental rehabilitation in difficult conditions of soft and hard tissues.

A customised digitally engineered solution for fixed dental rehabilitation in severe bone deficiency: A new innovative line extension in implant dentistry.

OBJECTIVES: Numerous procedures including soft and hard tissue reconstructions are necessary to allow for final implant-borne dental rehabilitation in patients with severe alveolar atrophy or resected jaws. In these cases, customised digitally engineered patient solutions for fixed or removable dental rehabilitation provide an innovative line extension to conventional implant dentistry. MATERIAL AND METHODS: A wax-up was performed on plaster models that were scanned by 3D laser. The generated stereolithographic files were then fused with the preoperative 3D imaging data. The individualised "dental" patient solutions were designed digitally and comprised a skeletonised anchorage system and a suprastructure connection system. Insertion of the implants was performed on an outpatient basis. Conventional implant-supported prosthodontic rehabilitation was performed. RESULTS: This digital planning algorithm can be applied to manufacture individualised patient solutions. Similar to conventional implant-supported dentures, these implants can be equipped with individual suprastructure connection systems for internal conical connection, ball-retained attachment, and external conical (telescopic) connection. CONCLUSIONS: In patients with severe atrophy or resected jaws, particularly following ablative tumour surgery, customised digitally engineered solutions allow for an innovative, less invasive line extension to conventional implant dentistry. When conventional implant dentistry reaches its limits, they still offer a strategy for implant-borne dental rehabilitation.