Journal of Oral Implantology最新文献

Among the complications that can occur at dental implants, the fracture of any implant component is a relatively infrequent but clinically relevant problem. Because of their mechanical characteristics, small diameter implants are at higher risk of such complication. The aim of this laboratory and finite element method (FEM) study was to compare the mechanical behavior of a 2.9- and 3.3-mm-diameter implant with a conical connection under standard static and dynamic conditions, following the International Organization for Standardization (ISO) 14801:2017. Finite element analysis was performed to compare the stress distribution on the tested implant systems under a 300-N, 30° inclined force. Static tests were performed with a load cell of 2 kN; the force was applied on the experimental samples at 30° with respect to the implant-abutment axis, with an arm of 5.5 mm. Fatigue tests were performed with decreasing loads, at 2-Hz frequency, until 3 specimens survived without any damage after 2 million cycles. The emergence profile of the abutment resulted the most stressed area in finite element analysis, with a maximum stress of 5829 and 5480 MPa for 2.9- and 3.3-mm-diameter implant complex, respectively. The mean maximum load resulted in 360 N for 2.9-mm-diameter and 370 N for 3.3-mm-diameter implants. The fatigue limit was recorded to be 220 and 240 N, respectively. Despite the more favorable results of 3.3-mm-diameter implants, the difference between the tested implants could be considered clinically negligible. This is probably due to the conical design of the implant-abutment connection, which has been reported to present low stress values in the implant neck region, thus increasing the fracture resistance.

Satisfactory function, esthetics, and phonetics together with long-term stability and minimal complications are all considered as metrics that define a successful outcome. The current case report is documentation of a mandibular subperiosteal implant with a successful follow-up of 56 years. Numerous issues can be credited for the long-term successful outcome including selection of the patient, heedfulness of basic anatomic and physiologic principles, design of the implant and superstructure, surgical execution, application of sound restorative principles, conscientious hygiene, and clockwork recare. The case demonstrates intense cooperation and coordination among the surgeon, restorative dentist, and laboratory technical staff, together with long-lasting patient compliance. Execution of the treatment with a mandibular subperiosteal implant helped this patient overcome the status of a dental cripple. The highlight of the case is that it is the longest success ever documented in the history of any type of implant treatment.

The aim of this article was to compare baseline residual ridge height using Cone-beam Computed Tomography (CBCT) and panoramic radiographs. A secondary aim was to examine the magnitude of vertical bone gain 6 months after trans-crestal sinus augmentation and compare it between operators. Thirty patients, who underwent trans-crestal sinus augmentation simultaneously with dental implant placement, were included in this retrospective analysis. Surgeries were done by 2 experienced surgeons (EM and EG) using the same surgical protocol and materials. Preoperative residual ridge height was measured on panoramic and CBCT images. The final bone height and the magnitude of the vertical augmentation were measured on panoramic X ray taken 6 months after surgery. Mean residual ridge height measured preoperatively using CBCT was 6.07 ± 1.38 mm, whereas these same measurements on the panoramic radiographs yielded similar results (6.08 ± 1.43 mm), which were statistically insignificant (P = .535). Postoperative healing was uneventful in all cases. All 30 implants were successfully osseointegrated at 6 months. The mean overall final bone height was 12.87 ± 1.39 mm (12.61 ± 1.21 and 13.39 ± 1.63 mm for operators EM and EG, respectively; P = .19). Likewise, mean postoperative bone height gain was 6.78 ± 1.57 mm, which was 6.68 ± 1.32 and 6.99 ± 2.06 mm for operators EM and EG, respectively (P = .66). A moderate positive correlation was found between residual bone height and final bone height (r = 0.43, P = .002). A moderate negative correlation was found between residual bone height and augmented bone height (r = -0.53, P = .002). Sinus augmentation performed trans-crestally produce consistent results with minimal interoperator differences between experienced clinicians. Both CBCT and panoramic radiographs produced similar assessment of the preoperative residual bone height.

Sufficient bone volume is necessary for placing a dental implant in an ideal position. To restore severely insufficient bone volume, autogenous block graft procedures with various intraoral donor sites are presented in the literature. The aims of this retrospective study are to present the dimensions and volume of the potential ramus block graft site, and to evaluate possible effect of mandibular canal diameter and its position in relation to mandibular ramus block graft volume. Two-hundred cone-beam computed tomography (CBCT) images were evaluated. The maximum length, width, height, and volume of the potential ramus block graft site, mandibular canal diameter, mandibular canal-mandibular basis distance, and mandibular canal-crest distance were measured. Mandibular canal diameter, mandibular canal-crest distance, and mandibular canal-mandibular basis distance were 3.139 ± 0.446 mm, 15.376 ± 2.562, and 7.834 ± 1.285 mm, respectively. In addition, the dimensions of the potential ramus block graft sites were measured 11.156 ± 2.297 mm × 10.390 ± 3.420 mm × 8.816 ± 1.720 mm (height × length × width). Moreover, the potential ramus bone block volume was calculated as 1.076 ± 0.398 cm3. While a positive correlation was detected between mandibular canal-crest distance and the potential ramus block graft volume (r = .160, P = .025), a negative correlation was found between mandibular canal-mandibular basis distance and the potential ramus block graft volume (r = -.020, P = .001). Mandibular ramus is one of the predictable intraoral donor sites for bone augmentation procedures. However, ramus has some volumetric limitations related to its neighboring anatomic structures. It seems to be important to evaluate lower jaw in a 3-dimensional manner to prevent surgical complications.

The purpose of this case report is to feature an interesting case where a staged approach was used to manage a failed implant site that led to a late sinus graft infection and sinusitis with an oroantral fistula (OAF), by using functional endoscopic sinus surgery (FESS) and an intraoral press-fit block bone graft technique. Sixteen years ago, a 60-year-old female patient underwent maxillary sinus augmentation (MSA) with 3 implants placed simultaneously in the right atrophic ridge. However, No. 3 and 4 implants were removed due to advanced peri-implantitis. The patient later developed purulent discharge from the site, headache, and complained of air leakage due to an OAF. The patient was referred to an otolaryngologist for FESS to treat the sinusitis. Two months after FESS, the sinus was re-entered. Residual inflammatory tissues and necrotic graft particles in the OAF site were removed. A block bone harvested from the maxillary tuberosity was press-fitted to the OAF site and grafted. After 4 months of grafting, the grafted bone was well incorporated with the surrounding native bone. Two implants were successfully placed in the grafted site with good initial stability. The prosthesis was delivered 6 months after implant placement. After the 2 years of follow-up, patient was functioning well without sinus complications. Within limitation of this case report, the staged approach via FESS and intraoral press-fit block bone graft is an effective method that can be used to successfully manage OAF and vertical defects at the implant site.

Introduction: A sinus floor elevation via lateral window (LSFE) is one of the most widely used bone augmentation procedures for implant therapy in the posterior area of the maxilla.  Locating and preparing a correct opening window on the lateral sinus wall is a key step of this procedure. Conventionally, the surgeon design and locate the window after the flap is reflected based upon the information obtained from cone-beam computed tomography (CBCT) images or other diagnostic aids. Nevertheless, in spite of the advancements in CBCT imaging, clinicians may still experience hardship in situating and procuring meticulous access to the maxillary sinus by using CBCT alone. Therefore, in cases requiring a LSFE simultaneous to implant placement, a maxillary sinus surgical guide (MSSG) has been tested and reported to be the amiable method to be utilized as a conjunct, to prevent unpredictable consequences according to its application in implying both the direction for the implant and the location of the lateral window.

Case series: This article presents 3 clinical cases with a fully digital approach to guide the opening of the lateral wall of the maxillary sinus, as well as the simultaneous placement of a single implant in an ideal 3D position. Based on the CBCT images and intraoral scan, a surgical guide was fabricated base on 3D software. During the surgery, this teeth-supported template can be placed intraorally, guiding sinus window opening preparation.

Conclusion: This technique makes the sinus window opening procedure simple and predictable, reduces surgical time as well as the risk of complications, and allows the placement of the implant in the ideal 3D position.

Introduction: Significant alveolar bone resorption follows tooth extraction. Immediate implant placement alone is not sufficient to prevent this phenomenon.

Case presentation: In this clinical case, a fractured upper first premolar was replaced by an immediate implant and a customized healing abutment designed on the perimeter of the extractive alveolus. After 3 months, the implant was restored. The facial and interdental  soft  tissue  was maintained with  appreciable  success after 5 years. The pre- and 5-year-post-treatment CT scans showed no bone loss.

Conclusion: The use of an interim customized healing abutment helps preventing hard and soft tissues collapse.  This technique is very straightforward and might represent a smart preservation strategy when there is no indication for adjunctive hard or soft tissue grafting.

Introduction This study aimed to assess the effect of slice thickness of 3D printer in fabrication of surgical guide (SG) on the accuracy of dental implant placement. Materials and Methods After preparation of two dry human mandibles, Cone-beam computed tomography (CBCT) scans were obtained, and the location and direction of implants in the edentulous ridge of the mandible were identified using Romexis software. Data in STL format were transferred to a 3D printer and two SGs with 50 µm and 100 µm thicknesses were fabricated for each mandible. Drilling was performed using two SGs. The pre- and post-intervention CBCT scans were superimposed to measure the magnitude of differences. The two groups were compared using the Mann-Whitney U test. Results No significant difference was noted in SGs with 50 and 100 µm thicknesses in the coronal and apical regions of the implants or the depth of drilling. However, the difference in angular deviation was statistically significant. Conclusion Considering the higher accuracy of SGs with 50 µm thickness (despite the presence of a significant difference in AD between the SGs with different thicknesses), it is recommended to use a SG with 50 µm thickness in cases where anatomical limitations exist.

This study investigated the marginal and internal fit and retention of crowns fabricated using 4 different castable pattern production methods, namely plastic burn out coping, computer-aided design and computer-aided manufacturing (CAD-CAM) milled (CAD-CAM-M), CAD-CAM additive (CAD-CAM-A), and conventional. This study consisted of 5 groups including 2 different brands of burn out coping groups (Burn out-Straumann [Burn out-S] group and Burn out-Implance [Burn out-I] group), the CAD-CAM-M group, the CAD-CAM-A group, and the conventional group. A total of 50 metal crown copings were produced in each group with 10 metal crown copings. The marginal gap of the specimens was measured twice-both before and after the cementation and thermocycling processes using a stereomicroscope. A total of 5 specimens were selected randomly-1 from each group for scanning electron microscopy analysis and sectioned longitudinally. The pull-out test was performed on the remaining 45 specimens. The lowest marginal gap value was observed in the Burn out-S group before and after cementation with 88.54-97.48 μm, respectively, while the highest marginal gap was observed in the conventional group (186.27-200.58 μm). Implant systems did not significantly affect the marginal gap values (P > .05). Marginal gap values increased significantly after cementation and thermal cycling in all the groups (P < .0001). The highest retention value was measured in the Burn out-S group while the lowest in the CAD-CAM-A group. The highest occlusal cement gap values were observed in the coping groups (Burn out-S and Burn out-I groups), and the lowest in the conventional group in the scanning electron microscopy analysis. The marginal fit and retention values of the prefabricated plastic burn out coping technique was superior when compared with the other techniques, providing that internal fit was superior with the conventional technique.

One of the most challenging aspects of dental alveolar ridge augmentation surgery is achieving proper wound closure and uneventful healing. To date, most of the open flap approaches have been fraught with complications. Many of these complications can be eliminated if the soft tissue incision is placed away from the surgical site. This paper describes the clinical application of a remote incision in various ridge augmentation surgeries as developed by Dr Hilt Tatum. It is part of the concept of natural implant restoration in stable alveolar bone that Dr Tatum introduced in the early 1970s.