A segmental osteotomy with 3D virtual planning to move a malpositioned dental implant

Background Correct positioning and alignment of dental implants are crucial to successfully meet the aesthetic and functional criteria in implant-prosthetic rehabilitation. When an implant is in the wrong position, especially in the esthetical zone, there are limited options to solve it. Some techniques have been described to reposition implants, such as reverse torque, trephine drills, and segmental osteotomies; current approaches aim to reduce the damage of the periimplant tissues. Case presentation A 20-year-old man with good general health was referred to the oral and maxillofacial surgery department of the CES University, Medellin Colombia in 2017, He had undergone a previous camouflage orthodontic therapy for a dental Class III, which finished in 2014, posteriorly a dental implant was placed in 2015 to replace upper right lateral incisor (1.2) before vertical growth of maxilla was complete; therefore, the implant was retained in a coronal position. A segmental osteotomy was suggested to reposition the implant in a more caudal position, a 3D surgical cut guide obtained by virtual planning was used to increase osteotomy accuracy and lower human error, to avoid the risk of damaging the adjacent tissues and to achieve a predictable result. Conclusions The segmental alveolar osteotomy is an effective alternative to reposition an implant; however, it must be carefully planned because human error remains a possibility that may affect the final result. Therefore, 3D planning is a better way to minimize these mistakes during the surgical procedure and the final position of the implant.

Bioactivity of an Experimental Dental Implant with Anodized Surface

Background: Several studies proved that anodic oxidation improves osseointegration. This study aimed to optimize osseointegration through anodization in dental implants, obtaining anatase phase and controlled nanotopography. Methods: The division of the groups with 60 titanium implants was: control (CG); sandblasted (SG); anodized (AG): anodized pulsed current (duty cycle 30%, 30 V, 0.2 A and 1000 Hz). Before surgery, surface characterization was performed using Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), X-ray Dispersive Energy Spectroscopy (EDS) and Raman Spectroscopy. For in vivo tests, 10 New Zealand white rabbits received an implant from each group. The sacrifice period was 2 and 6 weeks (n = 5) and the specimens were subjected to computed microtomography (μCT) and reverse torque test. Results: AFM and SEM demonstrated a particular nanotopography on the surface in AG; the anatase phase was proved by Raman spectroscopy. In the μCT and in the reverse torque test, the AG group presented better results than the other groups. Conclusion: The chemical composition and structure of the TiO2 film were positively affected by the anodizing technique, intensifying the biological characteristics in osseointegration.

Temporal Changes in Reverse Torque of Locking-Head Screws Used in the Locking Plate in Segmental Tibial Defect in Goat Model

The objective of this study was to evaluate changes in peak reverse torque (PRT) of the locking head screws that occur over time. A locking plate construct, consisting of an 8-hole locking plate and 8 locking screws, was used to stabilize a tibia segmental bone defect in a goat model. PRT was measured after periods of 3, 6, 9, and 12 months of ambulation. PRT for each screw was determined during plate removal. Statistical analysis revealed that after 6 months of loading, locking screws placed in position no. 4 had significantly less PRT as compared with screws placed in position no. 5 (p < 0.05). There were no statistically significant differences in PRT between groups as a factor of time (p > 0.05). Intracortical fractures occurred during the placement of 151 out of 664 screws (22.7%) and were significantly more common in the screw positions closest to the osteotomy (positions 4 and 5, p < 0.05). Periosteal and endosteal bone reactions and locking screw backout occurred significantly more often in the proximal bone segments (p < 0.05). Screw backout significantly, negatively influenced the PRT of the screws placed in positions no. 3, 4, and 5 (p < 0.05). The locking plate-screw constructs provided stable fixation of 2.5-cm segmental tibia defects in a goat animal model for up to 12 months.

Biomechanical and biochemical evaluation of the effect of systemic application of omeprazole on the osseointegration of titanium implants

Background This study aimed to investigate the effects of systemic omeprazole treatment on the osseointegration of titanium implants. Material and methods After surgical insertion of titanium implants into the metaphyseal part of rats’ both right and left tibial bones, the animals were randomly divided into three equal groups: control (n = 8), omeprazole dosage-1 (n = 8) (OME-1), and omeprazole dosage-2 (n = 8) (OME-2) and totally 48 implants were surgically integrated. The rats in the control group received no treatment during the four-week postoperative experimental period. In the OME-1 and OME-2 groups, the rats received omeprazole in doses of 5 and 10 mg/kg, respectively, every 3 days for 4 weeks. After the experimental period, the rats were euthanized. One rat died in each group and the study was completed with seven rats in each group. Blood serum was collected for biochemical analysis, and the implants and surrounding bone tissue were used for biomechanical reverse-torque analysis. In the biomechanical analysis, implants that were not properly placed and were not osseointegrated were excluded from the evaluation. Results One-way analysis of variance and Tukey’s honestly significant difference test and Student’s t test were used for statistical analysis. The reverse-torque test (control (n = 9), OME-1 (N = 7), and OME-2 (n = 7)) analysis of biochemical parameters (alkaline phosphatase, calcium, phosphorus, aspartate aminotransferase, alanine amino transferase, urea, and creatinine) revealed no significant differences between the groups (control (n = 7), OME-1 (N = 7), and OME-2 (n = 7)) (P > 0.05). Conclusions Omeprazole had no biomechanical or biochemical effects on the osseointegration process of titanium implants.

OCCLUSAL TRAUMA OF IMPLANT-SUPPORTED METAL-CERAMIC CROWN: A CASE REPORT

In this article there is a clinical case of occlusion trauma of implant-supported metal-ceramic crown for prosthetics of central incisor. Its uniqueness is the possibility to save dental implant after acute occlusion impact, which was strong enough to break ceramic facing of fixed denture, but not able to destroy bone and implant components. The occlusion force located at the incisal edge of the crown induced a reverse torque to the implant and did not result in its failure or bone resorption. In a year after repeated fixed prosthetics, the results of clinical examination proved absence of any problem with osseointegration. Literature analysis lets us to suggest, that the phenomenon was caused by protective action of cortical bone around of dental implant. Besides, in the case of natural tooth, the bone is suddenly compressed against the conical root; it transfers occlusal breaking to the supporting periodontal ligament. A dental implant has no periodontal ligament but can have a rough surface that may preclude implant failure.

A Novel Technique Using Polytetrafluoroethylene Tape to Solve Screw Loosening Complication in Implant-Supported Single Crowns

This study aimed to analyze a novel technique to make screws with greater untightening resistance and to solve screw loosening in implant-supported single crowns. Thirty grade IV titanium straight abutments were screwed onto 30 external hex implants using grade IV titanium screws (30 Ncm). They were exposed to cyclic loading (300,000 cycles, 200 N). Samples were divided into 4 groups (15 samples per group): new screws (SCREW group) (control), reused screws (rSCREW group), new screws wrapped with polytetrafluoroethylene (PTFE) tape (PTFE group), and reused screws wrapped with PTFE tape (rPTFE group). Reverse torque values (RTVs) were recorded with a digitally calibrated implant motor. Mean RTVs observed were 14.46 N (±1.10 N) for the control group, 14.42 N (±1.22 N) for the rSCREW group, 19.97 N (±1.16 N) for the PTFE group, and 19.13 N (±2.38 N) for the rPTFE group. Statistically significant differences were found between RTVs of both groups employing screws without PTFE tape (SCREW and rSCREW groups) compared with those using screws wrapped with PTFE tape (PTFE and rPTFE) (p < 0.001). These results suggest that wrapping the implant–abutment screw with PTFE tape may effectively lower the risk of loosening and even constitute a solution when this complication occurs in implant single crowns.

Comparing Torque Loss in Standard Implants and Short Implants with Increased Vertical Cantilever Abutments: an In Vitro Study

Objectives: With regard to the prevalence of abutment screw loosening (SL) and bone height reduction, particularly in the posterior regions of the jaws, as well as the contradictory issue of applying short implants instead of surgeries, along with all preparations associated with longer implants, the present study aimed to compare the amount of torque loss in short implants with increased vertical cantilever abutments and standard ones. Material and Methods: In this experimental study, a total number of 20 implants (MegaGen Implant Co., Ltd, South Korea) with 4.5 mm diameter including 10 short implants (7 mm) and 10 standard ones (10 mm) were utilized. Using a surveyor, fixtures were perpendicularly mounted in 13×34 mm resin for short implants and 19×34 mm resin for standard ones. The abutments of the same height but different cuff heights (2.5 mm for the standard implants and 5.5 mm for the short ones) were then tightened with 30 N.cm, via a digital torque meter. To compensate the settling effect, the abutment screw was re-tightened with 30 N.cm after 10 min. Upon applying 500,000 cycles at 75 N.cm and 1 Hz along the longitudinal axis on each sample, blind reverse torque value (RTV) was measured with a digital torque meter. The data were finally analyzed using Student’s t-test. Results: Both groups experienced torque loss, but there was no statistically significant difference between the case and control groups in terms of abutment SL (p = 0451). Conclusion: Short implants seem to be a good mechanical alternative in emergencies with respect to torque loss and abutment SL. KEYWORDS Reverse torque value; Cyclic loading, Short implant; Screw loosening; Crown-implant ratio; Torque loss.