Implants placed in an alveolar ridge with a sloped configuration. A 3-year prospective multicenter study.

AIM: The aim of the present study was to evaluate soft and hard tissue alterations around implants with a modified marginal portion placed in a healed, sloped ridge over 3 years of follow-up. MATERIAL AND METHODS: 65 patients with a single recipient implant site in an alveolar ridge with a lingual-buccal sloped configuration were recruited. Implants with a modified geometry in the marginal portion were installed in such a way that the sloped part of the device was located at the buccal and most apical position of the osteotomy preparation. Crowns were placed 21 weeks after implant placement. Radiologic examinations were performed at implant installation and at 1 and 3 years of follow-up. Bleeding on probing (BoP), probing pocket depth (PPD), and clinical attachment level (CAL; from the crown margin) were recorded at the insertion of the prosthesis and after 1 and 3 years. RESULTS: 57 patients with 57 implant-supported restorations attended the 3 years follow-up examination. The radiographic analysis revealed a mean marginal bone loss of 0.57 mm during the 3 years period. While the average bone loss between 1 and 3 years amounted to 0.30 mm, approximately 50% of the implants showed no bone loss during this period. The results from the clinical examinations showed a CAL gain of 0.11 ± 0.85 mm between baseline and 3 years of follow-up. About 65% of the implants showed no loss of attachment between 1 and 3 years. BoP and PPD ≥5 mm were identified at <10% of implants at the 3 years examination. CONCLUSION: Hard and soft tissues formed around dental implants that were designed to match the morphology of an alveolar ridge with a lingual-buccal sloped configuration remained stable over 3 years.

Pitfalls of Surgeon-Engineer Communication and the Effect of In-House Engineer Training During Digital Planning of Patient-Specific Implants for Orbital Reconstruction.

PURPOSE: The use of patient-specific implants for reconstruction of complex orbital floor defects is increasing and requires communication with an industry partner, which warrants investigation. Therefore, the aim of this study was to evaluate the effects of in-house training of engineers on such communication as well as to identify frequent sources of problems and their solutions for improvement of the implant-planning workflow. METHODS: We conducted a retrospective cross-sectional study and enrolled a sample of patients who had undergone orbital reconstruction with patient-specific implants between 2017 and 2020. The predictor variables were in-house training (additional training completed in hospital or not) and implant complexity (complex [multiwalled implants] vs less complex [isolated orbital floor reconstructions]). The outcome variables were duration of communication, message length, and need for synchronous communication or modifications to the original design. Descriptive, univariate, and multivariate statistics were computed, and statistical significance was set at a P value of < 0.05. RESULTS: This study included the data of 66 patients (48 men and 18 women, average age: 42.27 years). The complexity of the implant statistically significantly increased the duration of the communication (8.76 vs 16.03 days; P = .004). In 72.73%, the initial design had to be changed. Engineers trained in house required less communication to plan less-complex implants and generally needed fewer corrections to the original design (P = .020 and P = .036, respectively). Problems during planning were observed in 25.76% of the cases, with an insufficient diagnostic 3-dimensional data set being the most common (15.15%). CONCLUSIONS: In-house training of engineers is time-saving while planning the workflow for patient-specific implants, especially in less-complex cases, given that design changes are not needed often. The high rate of data sets that were insufficient for planning patient-specific implants suggests that diagnostic 3-dimensional data sets should already meet the requirements for such planning.

[Complex reconstructions in the facial and cranial regions]. / Komplexe Rekonstruktionen im Gesichts- und im Schädelbereich.

Posttraumatic reconstruction of the neurocranium and viscerocranium is an essential part of modern oral and maxillofacial surgery, in addition to oncological surgery, surgery of congenital craniofacial deformities and dental surgery. Due to the complex anatomy of the facial skull and significant esthetic and functional demands on its reconstruction, reconstructive trauma surgery in this area places the highest demands on the surgeon. This is all the more true if definitive craniomaxillofacial surgical treatment can sometimes only be performed with considerable delays for the benefit of other life-threatening injuries. In order to take these prerequisites into account, achievements of modern biomedical technology, such as intraoperative real-time navigation, computer-assisted planning and computer-assisted manufacturing (CAD/CAM) of patient-specific biomodels and implants, came up early for use in oral and maxillofacial surgery. In combination with intraoperative three-dimensional imaging, these methods result in a treatment pathway tailored to the individual patient, which is directly checked for quality at every step and thus ensures the best possible result for the patient. The use of these technologies extends far beyond the original indications in the area of orbital reconstruction and restoration of bony defects with simple geometry, such as skull defects. Nowadays, even the most complex pan-facial fractures can be restored esthetically and functionally by means of digitalized preliminary planning and individualized skull, orbital and zygomatic implants as well as total temporomandibular joint prostheses.

Angiogenic effects of mesenchymal stem cells in combination with different scaffold materials.

Tissue survival in regenerative tissue engineering requires rapid vascularization, which is influenced by scaffold material and seeded cell selection. Poly-l-lactide-co-glycolide (PLGA) and beta-tricalcium phosphate (ß-TCP) are well-established biomaterials with angiogenic effects because of their material properties. Given the importance of the seeded cell type as a co-factor for vascularization, mesenchymal stem cells (MSCs) are known to have high angiogenic potential. We hypothesized that PLGA and ß-TCP scaffolds seeded with MSCs would effectively induce a potent angiogenic response. Therefore, we studied the angiogenic effects after implanting PLGA and ß-TCP scaffolds seeded with isogeneic MSCs in vivo. Fifty-six BALB/c mice were equally divided into seven groups and underwent implantation of the dorsal skinfold chambers. Two MSC groups were seeded on collagen-coated PLGA or ß-TCP scaffolds, whereas groups 3-6 received collagen-coated or uncoated scaffolds without MSCs. No scaffold implantation was performed for group 7, which served as the control. Angiogenesis was assessed in vivo via intravital fluorescence microscopy. Angiogenic responses were noted on all scaffolds, whereupon MSC angiogenic response was significantly enhanced on days 6 and 10. Additionally, a comparison of biomaterials indicated increased angiogenic activity for ß-TCP scaffolds compared with PLGA scaffolds. In conclusion, seeding ß-TCP scaffolds with MSCs can accelerate vitalization and a combination of both significantly improves angiogenesis.

Three-dimensional analysis of the velopharyngeal region in patients with cleft palate and healthy individuals.

PURPOSE: This study aims to attain metric data of the velopharyngeal dimensions of healthy subjects as well as patients with velopharyngeal insufficiency using the example of cleft and lip palate (CLP) in order to determine possible differences in the volumes of both groups. METHODS: Volumes and distances of velopharyngeal areas were analyzed retrospectively using cone beam computed tomography data sets (n = 60). Group 1 included healthy patients receiving dental implants (n = 31). Group 2 was represented by patients with surgically closed cleft lip and palate (n = 29). RESULTS: Biggest differences among mean values of both groups were found for: minimum axial area (p = 0.000), airway area caudal (p = 0.000), distance between posterior nasal spine and posterior pharyngeal wall (PPW) (p = 0.014), mean distance between velum and PPW (p = 0.000), length of PPW (p = 0.000) and length of anterior pharyngeal wall (p = 0.000). CONCLUSION: Differences in the shape and geometry of the velopharyngeal area in subjects with a regular velopharyngeal structure and function and patients with cleft palate do exist. The significant differences found here can be categorized into two groups: one reflects distances between the anterior and posterior pharynx, presenting longer distances for patients with CLP. The second significant difference regards values of length in cranio-caudal direction, which is longer in healthy subjects. With regards to these values, one could conclude, that even though total volumes of both groups did not differ in size, group 1 shows three-dimensional velopharyngeal shapes that are longer and narrower, whereas shapes of patients of group 2 tend to be wider and shorter in general.

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.

Nasolabial Flap Improves Healing in Medication-Related Osteonecrosis of the Jaw.

PURPOSE: Medication-related osteonecrosis of the jaw (MRONJ) is an adverse side effect of antiresorptive and antiangiogenic therapeutic agents that is difficult to treat owing to its high relapse rate. The aim of the present study was to determine whether patients with MRONJ treated using decortication and a nasolabial flap compared with those who underwent decortication with mucoperiosteal flaps have better outcomes regarding stable wound closure. MATERIALS AND METHODS: Two groups of patients with MRONJ and intraoral exposed bone were evaluated in a cohort clinical study retrospectively. The primary predictor variable was the treatment group. The experimental group used the nasolabial flap for wound closure, and the control group used the mucoperiosteal flap for closure. The outcome variable was successful wound closure defined as a symptomless and closed wound after at least 12 months. Other study variables included factors such as perioperative drug holiday, duration of postoperative oral antibiotic administration, and postoperative use of nasogastric feeding tubes. Cox proportional hazard regression analysis and Kaplan-Meier curves were used to determine the factors independently associated with the dependent variable. The Mann-Whitney U test and χ2 test were used for analyses regarding group-related data. RESULTS: Both groups showed similar demographics. The 16 study patients receiving nasolabial flaps had a mean age of 69.9 years, and the 16 control patients receiving mucoperiosteal flaps had a mean age of 71.8 years. Both groups included 10 women and 6 men. Of the 16 patients in each group, 15 had received a bisphosphonate and 1, monoclonal antibody therapy. All evaluated patients underwent combined treatment, including decortication and intravenous antibiotics. Of the 16 patients receiving nasolabial flaps, symptomless intact wound closure was achieved in 68.8%. Of the 16 patients with mucoperiosteal closure, 18.7% achieved wound closure, with 81.2% developing a relapse of MRONJ, a statistically significant difference (P < .001). No statistically significant differences were found between the 2 groups in the demographic variables. The mean interval to relapse for the experimental and control groups was 13.6 ± 7.8 and 8.2 ± 7.9 months, respectively (P = .017). CONCLUSIONS: MRONJ is a complication of antiosteoclastic treatment of mostly oncologic, palliative patients, which requires a very methodical approach to surgical treatment. A variety of different methods have been reported. The use of nasolabial flaps can be considered as a highly reliable option for coverage the bone wound with less morbidity than microvascular free flaps and better long-term results compared with mucoperiosteal flaps.

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.

A prospective clinical study to evaluate the performance of zirconium dioxide dental implants in single-tooth edentulous area: 3-year follow-up.

BACKGROUND: Traditionally, dental implants have been made from titanium or titanium alloys. Alternatively, zirconia-based ceramic implants have been developed with similar characteristics of functional strength and osseointegration. Ceramic implants offer advantages in certain settings, e.g. in patients who object to metal dental implants. The aim of this study was to investigate the mid-term (36 months) clinical performance of a ceramic monotype implant in single-tooth edentulous area. METHODS: This was a prospective, open-label, single-arm study in patients requiring implant rehabilitation in single-tooth edentulous area. Ceramic implants (PURE Ceramic Implant, Institut Straumann AG, Basel, Switzerland) with a diameter of 4.1 mm were placed following standard procedure and loaded with provisional and final prostheses after 3 and 6 months, respectively. Implant survival rate and implant success rate were evaluated and crestal bone levels were measured by analysing standardized radiographs during implant surgery and at 6, 12, 24 and 36 months. RESULTS: Forty-four patients received a study implant, of whom one patient withdrew consent after 3 months. With one implant lost during the first 6 months after surgery, the implant survival rate was 97.7% at 6 months. No further implants were lost over the following 30 months, and 3 patients were lost to follow-up during this time frame. This led to a survival rate of 97.5% at 36 months. Six months after implant surgery 93.0% of the implants were considered "successful", increasing to 97.6% at 12 months and remaining at this level at 24 months (95.1%) and 36 months (97.5%). Bone loss was most pronounced in the first half-year after implant surgery (0.88 ± 0.86 mm). By contrast, between 12 and 36 months the mean bone level remained stable (minimal gain of 0.06 [± 0.60] mm). Hence, the overall bone loss from implant surgery to 36 months was 0.97 (± 0.88) mm. CONCLUSIONS: In the follow-up period ceramic implants can achieve favourable clinical outcomes on a par with titanium implants. For instance, these implants can be recommended for patients who object to metal dental implants. However, longer term studies with different edentulous morphology need to confirm the present data. TRIAL REGISTRATION: Registered on www.clinicaltrials.gov : NCT02163395 .

Neck Dissection's Burden on the Patient: Functional and Psychosocial Aspects in 1,652 Patients With Oral Squamous Cell Carcinomas.

PURPOSE: In this study of patients with oral squamous cell carcinoma, the authors sought to clarify the functional and psychosocial harms of neck dissection (ND), which lessens quality of life. MATERIALS AND METHODS: The study included questionnaire responses from patients with oral squamous cell carcinoma (n = 1,652) and clinicians (n = 1,489), as collected in the DÖSAK Rehab Study. Psychosocial and functional factors were assessed. Functional and psychosocial outcomes in patients who did not receive ND were compared with those in patients who underwent selective supraomohyoid ND (SND), modified radical ND (MND), and radical ND (RND). RESULTS: Patients with ND had lower quality of life than those without ND. Burdens after SND (n = 923) were generally lesser than those after MND (n = 301) or RDN (n = 678). There were meaningful differences between the SND, MND, and RND and without-ND groups in impairments in speech intelligibility for strangers and familiar persons, ingestion and swallowing, tongue mobility, opening of the mouth, lower jaw mobility, neck mobility, and shoulder and arm movement (P < .05). Many patients with ND faced a lower functional status and negative professional and financial consequences. CONCLUSIONS: Because of the burdens associated with ND, the decision to perform this treatment for oral squamous cell carcinoma should incorporate information on health-related quality of life and survival rates.

A prospective clinical study to evaluate the performance of zirconium dioxide dental implants in single-tooth gaps.

INTRODUCTION: Dental implants have traditionally been made from titanium or its alloys, but recently full-ceramic implants have been developed with comparable osseointegration properties and functional strength properties to titanium. These ceramic implants may have advantages in certain patients and situations, for example, where esthetic outcomes are particularly important. OBJECTIVE: The objective of this investigation was to evaluate the performance of a newly developed full-ceramic ZrO2 monotype implant design (PURE Ceramic Implant; Institut Straumann AG, Basel, Switzerland) in single-tooth gaps in the maxilla and mandible. MATERIAL AND METHODS: This was a prospective, open-label, single-arm study in patients requiring implant rehabilitation in single-tooth gaps. Full-ceramic implants were placed, with provisional and final prostheses inserted after 3 and 6 months, respectively. Crestal bone level was measured at implant placement and after 6 and 12 months. Implant survival and success were evaluated after 6 and 12 months. Further evaluations are planned after 24 and 36 months. RESULTS: Forty-six patients were screened for potential study participation, of whom 44 (17 men and 27 women, mean age 48 ± 14 years) were recruited into the study. The majority of implants (90.9%) were placed in the maxilla. The implant survival and implant success rate after 12 months were 97.6%. A minor change of the mean bone level occurred between implant loading (final prosthesis insertion after 6 months) and 12 months (-0.14 mm) after initial bone remodeling was observed between implant placement and loading (-0.88 mm). CONCLUSIONS: The results indicated that monotype ceramic implants can achieve clinical outcomes comparable to published outcomes of equivalent titanium implants.

Perioperative Bromelain Therapy after Wisdom Teeth Extraction - A Randomized, Placebo-Controlled, Double-Blinded, Three-Armed, Cross-Over Dose-Finding Study.

Reduction in postoperative edema and inflammatory reactions is the key to the posttraumatic regeneration process. Use of bromelain is well established in this indication, but there is some controversy with regard to the optimal dosing of this drug. The aim of our study was therefore to investigate the efficacy of dosage-dependent therapy with bromelain in patients after wisdom teeth extraction by comparing the registered dosage 1000 FIP (Fédération Internationale Pharmaceutique) against higher dosages of 3000 FIP and 4500 FIP. A total of 75 patients were randomized to one of the three dosage arms, and 68 of these patients were finally analyzed in the modified intention-to-treat population. Patients involved underwent two surgery sessions: one study period being conducted under treatment with bromelain and the other with placebo. Postoperative swelling determined by a 3D face scanning system was defined as the primary endpoint; further efficacy parameters were maximum swelling, pain, difficulty in swallowing, and use of analgesics. A superiority of treatment with 3000 FIP and 4500 FIP versus 1000 FIP could not be demonstrated. The analysis of pooled bromelain treatments versus placebo did, however, show a clear trend in favor of bromelain for all assessments. Adverse events did not occur more frequently under bromelain therapy compared with placebo. This study thus clearly supports the clinical relevance of treatment of postoperative conditions with bromelain, and the recommended daily dose was sufficiently effective in this trial and indication. Copyright © 2016 John Wiley & Sons, Ltd.

Modified technique for rehabilitation of facial paralysis using autogenous fascia lata grafts.

PURPOSE: In this retrospective study we used a modified surgical technique for midface reanimation in patients with facial nerve paralysis. Facial atonicity can cause functional impairment regarding speech articulation, oral competence, breathing, and eyelid closure. Furthermore, esthetic and psychological aspects play an important role in patients' emotional interaction and social integration. The chosen rehabilitative technique should offer support against prolapse of facial structures and remedy of functional disabilities and, thereby, prevention of social stigmatization due to disease-related changes in appearance. MATERIALS AND METHODS: Between 2005 and 2013, fascia lata grafts were used as static support in 15 cases of unilateral facial paralysis. Two fascia lata grafts were subcutaneously inserted in the upper and lower lips crossing the midline and sutured at 4 points, including the unaffected part of the orbicularis oris muscle and modiolus. The slings were suspended against the zygomatic arch with an osteosynthesis plate. RESULTS: The patients perceived surgery results as considerably improving their appearance, speech, and alimentation. In 93.3% of cases, no postoperative complications occurred. The follow-up results (8 months to 8 years) remained stable. CONCLUSIONS: This retrospective study showed the advantages of static facial reanimation in appropriate cases. The bony fixated support of the fascial slings allows an immediate improvement of facial symmetry. Additional attachment points including the unaffected part of the orbicularis oris muscle and the use of 2 independent fascia lata slings allow a more accurate adjustment of suspension forces and an incomplete dynamic reanimation of the mouth corner. With respect to its simplicity and minimal invasiveness, this surgical procedure is associated with low morbidity and rapid improvement of the patient's esthetic appearance.

Increasing the accuracy of orbital reconstruction with selective laser-melted patient-specific implants combined with intraoperative navigation.

PURPOSE: Advances in technology have allowed increasing degrees of accuracy in the treatment of orbital deformities. The purpose of this study was to compare the accuracy of pre-bent titanium mesh (PBTM) and selective laser-melted patient-specific implants (PSIs) in unilateral orbital reconstruction after traumatic injury. The authors hypothesized that selective laser-melted PSIs would more accurately reconstruct the orbit. MATERIALS AND METHODS: A retrospective review of 34 cases of primary reconstruction of unilateral orbital fractures treated using selective laser-melted PSIs (group 1, n = 17) or PBTM (group 2, n = 17) was performed. The primary outcome measurements were orbital volume excess and the anterior, medial, and posterior intraorbital angles. The Mann-Whitney U test was used to assess the difference in orbital volume and angular deviation between the 2 groups. The level of statistical significance was set at .05. All P values were 2-sided. RESULTS: The comparison of mean values for the 2 groups showed significant differences for the anterior angle (PBTM: mean, 11.3; standard deviation [SD], 1.8; PSI: mean, 4.1; SD, 0.7; P = .001), but not the medial (PBTM: mean, 11.6; SD, 2.0; PSI: mean, 8.2; SD, 1.9; P = .170) and posterior (PBTM: mean, 10.8, SD, 2.8; PSI: mean, 8.2, SD, 1.4; P = .760) angles between the unaffected and reconstructed orbits. The postoperative difference in volume between the unaffected and reconstructed orbits differed significantly between the 2 study groups (PBTM: mean, 0.6; SD, 0.1; PSI: mean, 0.4; SD, 0.1; P = .029). CONCLUSION: The results of this study suggest that complex orbital fractures can be reconstructed with an even higher degree of accuracy with selective laser-melted PSIs than with PBTM.

Presentation and Evaluation of a Modified Wax-Bite Dental Splint for Surgical Navigation in Craniomaxillofacial Surgery.

PURPOSE: The purpose of the present study was to introduce and evaluate the use of a modified "wax-bite dental splint" for surgical navigation in craniomaxillofacial surgery. MATERIALS AND METHODS: A 2-layer wax bite dental splint was fabricated with an anterior extension, and 8 gutta percha markers were incorporated in each splint for marker-based pair-point registration. To evaluate the accuracy, the occlusal registration of the wax bite dental splint was performed on 10 artificial skulls. Consecutively, all the skulls were scanned using a standardized cone-beam computed tomography scanning protocol with the 2-layer wax bite dental splint in place. Automatic rigid marker-based pair-point registration was performed using the iPlan CMF software, version 3.0 (Brainlab AG, Feldkirchen, Germany) using 8 gutta percha markers incorporated into the wax bite dental splint. Additionally, the registration accuracy of 6 anatomic skeletal landmarks was measured on each skull. RESULTS: The mean registration error for each wax bite dental splint ranged from 0.78 to 1.01 mm. The overall mean registration error for the wax-bite dental splint-based registration was 0.89 ± 0.08 mm. The mean registration error for the 6 anatomic landmarks ranged from 1.23 to 2.3 mm. The overall mean registration error was 1.68 ± 0.28 mm. CONCLUSION: The results of the present study show the potential for a wax-bite dental splint as an alternative rigid registration method for surgical navigation in craniomaxillofacial surgery. Moreover, from a clinical viewpoint, the method is accurate, user-friendly, inexpensive, and not time-consuming.

Template-guided vs. non-guided drilling in site preparation of dental implants.

OBJECTIVES: Clinical success of oral implants is related to primary stability and osseointegration. These parameters are associated with delicate surgical techniques. We herein studied whether template-guided drilling has a significant influence on drillholes diameter and accuracy in an in vitro model. MATERIALS AND METHODS: Fresh cadaveric porcine mandibles were used for drilling experiments of four experimental groups. Each group consisted of three operators, comparing guide templates for drilling with free-handed procedure. Operators without surgical knowledge were grouped together, contrasting highly experienced oral surgeons in other groups. A total of 180 drilling actions were performed, and diameters were recorded at multiple depth levels, with a precision measuring instrument. RESULTS: Template-guided drilling procedure improved accuracy on a very significant level in comparison with free-handed drilling operation (p ≤ 0.001). Inaccuracy of free-handed drilling became more significant in relation to measurement depth. High homogenic uniformity of template-guided drillholes was significantly stronger than unguided drilling operations by highly experienced oral surgeons (p ≤ 0.001). CONCLUSION: Template-guided drilling procedure leads to significantly enhanced accuracy. Significant results compared to free-handed drilling actions were achieved, irrespective of the clinical experience level of the operator. CLINICAL RELEVANCE: Template-guided drilling procedures lead to a more predictable clinical diameter. It shows that any set of instruments has to be carefully chosen to match the specific implant system. The current in vitro study is implicating an improvement of implant bed preparation but needs to be confirmed in clinical studies.

Poly-ε-caprolactone Coated and Functionalized Porous Titanium and Magnesium Implants for Enhancing Angiogenesis in Critically Sized Bone Defects.

For healing of critically sized bone defects, biocompatible and angiogenesis supporting implants are favorable. Murine osteoblasts showed equal proliferation behavior on the polymers poly-ε-caprolactone (PCL) and poly-(3-hydroxybutyrate)/poly-(4-hydroxybutyrate) (P(3HB)/P(4HB)). As vitality was significantly better for PCL, it was chosen as a suitable coating material for further experiments. Titanium implants with 600 µm pore size were evaluated and found to be a good implant material for bone, as primary osteoblasts showed a vitality and proliferation onto the implants comparable to well bottom (WB). Pure porous titanium implants and PCL coated porous titanium implants were compared using Live Cell Imaging (LCI) with Green fluorescent protein (GFP)-osteoblasts. Cell count and cell covered area did not differ between the implants after seven days. To improve ingrowth of blood vessels into porous implants, proangiogenic factors like Vascular Endothelial Growth Factor (VEGF) and High Mobility Group Box 1 (HMGB1) were incorporated into PCL coated, porous titanium and magnesium implants. An angiogenesis assay was performed to establish an in vitro method for evaluating the impact of metallic implants on angiogenesis to reduce and refine animal experiments in future. Incorporated concentrations of proangiogenic factors were probably too low, as they did not lead to any effect. Magnesium implants did not yield evaluable results, as they led to pH increase and subsequent cell death.

SLM produced porous titanium implant improvements for enhanced vascularization and osteoblast seeding.

To improve well-known titanium implants, pores can be used for increasing bone formation and close bone-implant interface. Selective Laser Melting (SLM) enables the production of any geometry and was used for implant production with 250-µm pore size. The used pore size supports vessel ingrowth, as bone formation is strongly dependent on fast vascularization. Additionally, proangiogenic factors promote implant vascularization. To functionalize the titanium with proangiogenic factors, polycaprolactone (PCL) coating can be used. The following proangiogenic factors were examined: vascular endothelial growth factor (VEGF), high mobility group box 1 (HMGB1) and chemokine (C-X-C motif) ligand 12 (CXCL12). As different surfaces lead to different cell reactions, titanium and PCL coating were compared. The growing into the porous titanium structure of primary osteoblasts was examined by cross sections. Primary osteoblasts seeded on the different surfaces were compared using Live Cell Imaging (LCI). Cross sections showed cells had proliferated, but not migrated after seven days. Although the cell count was lower on titanium PCL implants in LCI, the cell count and cell spreading area development showed promising results for titanium PCL implants. HMGB1 showed the highest migration capacity for stimulating the endothelial cell line. Future perspective would be the incorporation of HMGB1 into PCL polymer for the realization of a slow factor release.

Comparison of Selective Laser Melted Titanium and Magnesium Implants Coated with PCL.

Degradable implant material for bone remodeling that corresponds to the physiological stability of bone has still not been developed. Promising degradable materials with good mechanical properties are magnesium and magnesium alloys. However, excessive gas production due to corrosion can lower the biocompatibility. In the present study we used the polymer coating polycaprolactone (PCL), intended to lower the corrosion rate of magnesium. Additionally, improvement of implant geometry can increase bone remodeling. Porous structures are known to support vessel ingrowth and thus increase osseointegration. With the selective laser melting (SLM) process, defined open porous structures can be created. Recently, highly reactive magnesium has also been processed by SLM. We performed studies with a flat magnesium layer and with porous magnesium implants coated with polymers. The SLM produced magnesium was compared with the titanium alloy TiAl6V4, as titanium is already established for the SLM-process. For testing the biocompatibility, we used primary murine osteoblasts. Results showed a reduced corrosion rate and good biocompatibility of the SLM produced magnesium with PCL coating.

Soft and hard tissue alterations around implants placed in an alveolar ridge with a sloped configuration.

AIM: The aim of this study was to evaluate soft and hard tissue alterations around implants placed in healed, sloped ridge sites. MATERIALS AND METHODS: In this prospective multi-center study, 65 patients between 20 and 74 years of age and with a need for a single tooth replacement were included. All patients presented with a recipient implant site demonstrating a lingual-buccal bone height discrepancy of 2.0-5.0 mm and with a neighboring tooth on its mesial aspect. Implant placement (OsseoSpeed™ Profile implants; Astra Tech AB, Mölndal, Sweden) was performed using a non-submerged installation procedure. The implants were placed in such a way that the sloped part of the device was located at the buccal and most apical position of the osteotomy preparation. As the buccal rim of the implant was positioned at the crestal bone level, the lingual rim became situated either below or at the level of the lingual bone crest. Clinical assessments of bone levels at the buccal and lingual aspects of the implant were carried out immediately after implant installation and at a surgical re-entry procedure performed 16 weeks later. Crowns were placed at 21 weeks after implant placement. Radiographs were obtained immediately after implant placement, at 16 and 21 weeks and at the 1-year re-examination. Clinical assessment of probing pocket depth and clinical attachment levels were carried out at 21 weeks and at 1 year of follow-up. RESULTS: The alterations of the bone levels that occurred between implant placement and the 16-week surgical re-entry were -0.02 mm (lingual) and -0.30 mm (buccal). The average change in interproximal bone levels between implant placement and the 1-year re-examination was 0.54 mm. Clinical attachment level changes between the 21 week and the 1-year examinations varied between 0.1 mm gain and 0.1 mm loss. CONCLUSION: Implant placement in an alveolar ridge with a sloped marginal configuration resulted in minor remodeling with preserved discrepancies between buccal and lingual bone levels.