Volkan Arısan

Accuracy of Two Stereolithographic Guide Systems for Computer-Aided Implant Placement: A Computed Tomography-Based Clinical Comparative Study

BACKGROUND Stereolithographic surgical guides provide significant benefits during the simultaneous placement of multiple implants with regard to the final prosthetic plan. However, deviation from the planning poses a significant risk. Deviations of implants that were placed by bone-, tooth-, and mucosa-supported stereolithographic surgical guides were examined in this study. METHODS After enrolling 54 eligible patients, 294 implants were planned on cone-beam computerized tomography CB(CT)-derived images. Sixty guides, both single- and multiple-type, were produced using two commercial systems. Mucosa-supported guides were fixed with osteosynthesis screws. Implants were inserted, and at the end of osseointegration period, a new CB(CT) scan was performed. Preoperative planning was merged with the new CB(CT) data to identify the deviations between the planned and placed implants for each support type and manufacturer. The Kruskal-Wallis and Mann-Whitney U tests were used for comparison (P <0.05). RESULTS There were no damage-related complications in any critical anatomy. Implants that were placed by bone-supported guides had the highest mean deviations (5.0 degrees +/- 1.66 degrees angular, and 1.70 +/- 0.52 mm and 1.99 +/- 0.64 mm for implant shoulder and tip, respectively), whereas the lowest deviations were measured in implants that were placed by mucosa-supported guides (2.9 degrees +/- 0.39 degrees angular, and 0.7 +/- 0.13 mm and 0.76 +/- 0.15 mm for implant shoulder and tip, respectively). CONCLUSIONS Computer-aided planning and manufacturing surgical guides in accordance with CB(CT) images may help clinicians place implants. Rigid screw fixation of a single guide incorporating metal sleeves and a special drill kit further minimizes deviations.

Implant surgery using bone‐ and mucosa‐supported stereolithographic guides in totally edentulous jaws: surgical and post‐operative outcomes of computer‐aided vs. standard techniques

OBJECTIVES The aim of this study was to compare the surgical and post-operative outcomes of a computer-aided implant surgery performed by bone- and mucosa-supported stereolithographic (SLA) guides against the standard technique. MATERIAL AND METHODS Multiple- and single-type SLA guides from two commercial manufacturers were produced and a total of 341 implants were placed to 52 patients using the standard technique (Control group), bone- (bone-supported guide [BSG] group) and mucosa-supported SLA guides (Flapless group) in 21, 16 and 15 patients, respectively. Surgical duration (min), number of analgesics (tablets) as well as hemorrhage, difficulty in mouth opening (or trismus) and other incidences were recorded. Pain and swelling was assessed using the visual analog scale (VAS). Parametric and non-parametric tests were used for statistical analysis (P<.05). RESULTS The mean surgery duration (23.53+/-5.48 min) and the number of analgesics consumed (four tablets) in the Flapless group were lower than those in the control (68.71+/-11.4 min and 10 tablets) and BSG groups (60.94+/-13.07 min and 11 tablets, P<0.01). The change in pain scores (VAS) and the number of analgesics consumed in time were statistically significant (P<0.01 and 0.05, respectively) and the Flapless group reported a lower pain score than the BSG (P<0.01) and Control groups (P<0.001). The Flapless group experienced less hemorrhage (chi(2)=4.12, P=0.041 on the day of surgery) and fewer instances of trismus (chi(2)=6.91, P=0.031 the day after surgery). The differences in early-term failures were not statistically significant between the groups (log-rank test: P=0.782). CONCLUSION The use of mucosa-supported single SLA guides for flapless implant placement may help reduce the surgery duration, pain intensity, related analgesic consumption and most other complications typical in the post-implant surgery period. However, there are particular drawbacks in both guide types and further studies are required to confirm the prosthodontic conformity and long-term success of implants placed using computer-assisted techniques.

Conventional multi-slice computed tomography (CT) and cone-beam CT (CBCT) for computer-assisted implant placement. Part I: relationship of radiographic gray density and implant stability.

PURPOSE The relationship of conventional multi-slice computed tomography (CT)- and cone beam CT (CBCT)-based gray density values and the primary stability parameters of implants that were placed by stereolithographic surgical guides were analyzed in this study. MATERIALS AND METHODS Eighteen edentulous jaws were randomly scanned by a CT (CT group) or a CBCT scanner (CBCT group) and radiographic gray density was measured from the planned implants. A total of 108 implants were placed, and primary stability parameters were measured by insertion torque value (ITV) and resonance frequency analysis (RFA). Radiographic and subjective bone quality classification (BQC) was also classified. Results were analyzed by correlation tests and multiple regressions (p < .05). RESULTS CBCT-based gray density values (765 ± 97.32 voxel value) outside the implants were significantly higher than those of CT-based values (668.4 ± 110 Hounsfield unit, p < .001). Significant relations were found among the gray density values outside the implants, ITV (adjusted r(2)  = 0.6142, p = .001 and adjusted r(2)  = 0.5166, p = .0021), and RFA (adjusted r(2)  = 0.5642, p = .0017 and adjusted r(2)  = 0.5423, p = .0031 for CT and CBCT groups, respectively). Data from radiographic and subjective BQC were also in agreement. CONCLUSIONS Similar to the gray density values of CT, that of CBCT could also be predictive for the subjective BQC and primary implant stability. Results should be confirmed on different CBCT scanners.

Osseointegration and stability of a modified sand-blasted acid-etched implant: an experimental pilot study in sheep

OBJECTIVE The aim of this pilot study was to compare the early-term osseointegration characteristics of standard (SLA) and modified sand-blasted and acid-etched (modSLA) implants in an experimental animal model. MATERIAL AND METHODS A total of 30 SLA and modSLA implants were placed to the tibiae of three sheep and the insertion torque value (ITV) and resonance frequency analysis (RFA) measurements were performed. RFA measurement was repeated on 3 and 6 weeks healed implants after which the animals were sacrificed for histomorphometric analysis. Bone-to-implant contact was assessed on the non-decalcified sections. Six weeks healed implants were also subjected to the reverse torque test (RTT). Results were analyzed by the Friedman test, Kruskal-Wallis test and Spearman rank correlation test. RESULTS All implants reached to a strong primary stability with a mean 36.13 ± 2.47 and 35.47 ± 2.85 N/cm ITV. In the surgical stage, RFA values for SLA and modSLA implants were found to be 72.27 ± 3.17 and 71.6 ± 2.87, respectively. After 3 weeks of healing, mean BIC% (80.64 ± 13.89%) and RFA value (76.8 ± 1.14) of modSLA implants were significantly higher (P=0.0002) than that of SLA implants (64.39 ± 21.2 BIC% and 74.2 ± 4.76 RFA). However, no statistically significant difference between SLA and modSLA implants was recorded after 6 weeks of healing. Both implants revealed similar results in the RTT test (115.2 ± 4.14 and 117 ± 4.47 N/cm for SLA and modSLA implants, respectively). No correlation was found between RFA and BIC%. CONCLUSION Within the limits of this pilot study, it can be concluded that modSLA implants achieve a higher bone contact and stability at earlier time points when compared with SLA implants.

The effect of injectable calcium phosphate cement on bone anchorage of titanium implants: an experimental feasibility study in dogs.

Calcium phosphate has high osteotransductive potential. The injectable form of calcium phosphate cement (ICAP) can be used as an adjunctive supportive agent for dental implants. The aim of this study was to assess the effect of an ICAP on the reverse torque resistance of titanium implants. Two implant beds (total 24) were prepared in each proximal tibia of 6 beagles. ICAP was injected into one of prepared implant beds (test) and the implant was inserted. The next implant was inserted without ICAP to serve as control. Three dogs were killed after 2 weeks and 3 after 12 weeks. Retrieved implants were subjected to reverse torque test. Results were analyzed with Students t-test. Scanning electron microscope (SEM) was used for further evaluation. Mean torque values in 2-week healed implants were 52.48 N cm and 50.57 N cm for test and control implants, respectively (p=0.4). 12-week healed implants showed 81.61 N cm and 76.71 N cm for test and control implants, respectively (p=0.14). Results indicated no statistical difference between test and control implants for either healing time. SEM images of tested samples revealed close contact between the bone-ICAP-titanium surface. ICAP must be tested on further developed experimental models.

Conventional multi-slice computed tomography (CT) and cone-beam CT (CBCT) for computer-aided implant placement. Part II: reliability of mucosa-supported stereolithographic guides.

PURPOSE Deviations of implants that were placed by conventional computed tomography (CT)- or cone beam CT (CBCT)-derived mucosa-supported stereolithographic (SLA) surgical guides were analyzed in this study. MATERIALS AND METHODS Eleven patients were randomly scanned by a multi-slice CT (CT group) or a CBCT scanner (CBCT group). A total of 108 implants were planned on the software and placed using SLA guides. A new CT or CBCT scan was obtained and merged with the planning data to identify the deviations between the planned and placed implants. Results were analyzed by Mann-Whitney U test and multiple regressions (p < .05). RESULTS Mean angular and linear deviations in the CT group were 3.30° (SD 0.36), and 0.75 (SD 0.32) and 0.80 mm (SD 0.35) at the implant shoulder and tip, respectively. In the CBCT group, mean angular and linear deviations were 3.47° (SD 0.37), and 0.81 (SD 0.32) and 0.87 mm (SD 0.32) at the implant shoulder and tip, respectively. No statistically significant differences were detected between the CT and CBCT groups (p = .169 and p = .551, p = .113 for angular and linear deviations, respectively). CONCLUSIONS Implant placement via CT- or CBCT-derived mucosa-supported SLA guides yielded similar deviation values. Results should be confirmed on alternative CBCT scanners.

A randomized clinical trial of an adjunct diode laser application for the nonsurgical treatment of peri-implantitis.

OBJECTIVE In this radiographic and microbiologic split-mouth clinical trial, efficacy of a diode laser as an adjunct to conventional scaling in the nonsurgical treatment of peri-implantitis was investigated. BACKGROUND DATA Eradication of pathogenic bacteria and infected sulcular epithelium presents a significant challenge in the nonsurgical treatment of peri-implantitis. MATERIALS AND METHODS Ten patients (mean age, 55.1 years; SD, 11.4) with 48 two piece, rough-surface implants and diagnosed with peri-implantitis were recruited (NCT02362854). In addition to conventional scaling and debridement (control group), crevicular sulci and the corresponding surfaces of 24 random implants were lased by a diode laser running at 1.0 W power at the pulsed mode (λ, 810 nm; energy density, 3 J/cm(2); time, 1 min; power density, 400 mW/cm2; energy, 1.5 J; and spot diameter, 1 mm); (laser group). Healing was assessed via periodontal indexes (baseline and after 1 and 6 months after the intervention), microbiologic specimens (baseline and after 1 month), and radiographs (baseline and after 6 months). RESULTS Baseline mean pocket depths (4.71, SD, 0.67; and 4.38, SD 0.42 mm) and marginal bone loss (2.71, SD 0.11; and 2.88, SD 0.18 mm) were similar (p = 0.09 and p = 0.12) between the control and laser groups, respectively. After 6 months, the laser group revealed higher marginal bone loss (2.79, SD 0.48) than the control groups (2.63, SD 0.53) (p < 0.0001). However, in both groups, the microbiota of the implants was found unchanged after 1 month. CONCLUSIONS In this clinical trial, adjunct use of diode laser did not yield any additional positive influence on the peri-implant healing compared with conventional scaling alone.

Vascular endothelial growth factor and biphasic calcium phosphate in the endosseous healing of femoral defects: An experimental rat study

Background/purpose The presence of adequate bone volume is a critical factor in rehabilitative dentistry. Despite the use of many promising alloplasts, success in stimulating bone formation has been limited, mostly due to poor local biological response. Growth factors have been introduced to stimulate angiogenesis and new bone formation. This histologic and histomorphometric study aimed to evaluate the effect of vascular endothelial growth factor (VEGF) and a biphasic alloplastic graft material (BA) on the healing of endosseous defects in rats. Materials and methods Twenty male Wistar rats were used. Two critical-sized bone defects were created in both the right and left femurs of each rat. Each defect was randomly assigned to be treated with VEGF, BA, or VEGF + BA, or to be left empty as a control. Half of the animals were sacrificed after 1 week, and the remaining half were sacrificed after 2 weeks. Inflammation, necrosis, and new bone areas were evaluated by means of histologic and histomorphometric analyses. Results Compared to the control group, defects treated with VEGF alone or in combination with BA showed higher rates of bone formation (33.10–46.60%) on Day 7. Additionally, VEGF significantly reduced inflammation and necrosis (P < 0.001). However, the differences were no longer discernable on Day 14. Conclusion VEGF makes a significant contribution to angiogenesis and osteogenesis in the early stages of bone defect healing, and its combination with an osteoconductive grafting material (BA) may further enhance new bone formation.

Full Mouth Oral Rehabilitation by Maxillary Implant Supported Hybrid Denture Employing a Fiber Reinforced Material Instead of Conventional PMMA.

Many people have life-long problems with their dentures, such as difficulties with speaking and eating, loose denture, and sore mouth syndrome. The evolution of dental implant supported prosthesis gives these patients normal healthy life for their functional and esthetic advantages. This case report presents the fabrication of maxillary implant supported hybrid prosthesis by using Nanofilled Composite (NFC) material in teeth construction to rehabilitate a complete denture wearer patient.

Biodegradation of Injectable Calcium Phosphate Bone Cements: A Dental Perspective

The prevalence of tooth loss and edentulism is among the most ubiquitous diseases of human history. Dental implants have been widely used for the treatment of any type of edentulism. However, the absence of sufficient bone volume usually limits the placement of implants. Many techniques and materials have been developed to restore an adequate volume of bone for future implant placement, but the process of biode‐ gradation and replacement with new bone tissue is still under debate for all grafting materials. Among the available biomaterials, calcium phosphates (CaP) have been under the spot light for their advantages such as the ease of production and lack of disease transfer. The preparation of the material in two phases allowed self-hardening and subsequent space maintenance where it applied. This was of critical importance in load-bearing implants and joint prosthesis where rapid and strong healing is re‐ quired. The injectability also allowed a better handling and manipulation in compro‐ mised areas such as the oral cavity. A novel form of injectable calcium phosphate cement (iCaP) with two distinct formulations was tested on dog tibiae. Healing and ossifica‐ tion at 4 and 12 weeks were assessed by histologic and histomorphometric analysis. No adverse reactions or negative consequences were noted. Mean new bone formation was 22.12 (SD, 15.68), 18.62 (SD, 13.11), and 9.56 (SD, 11.11)% in the groups 1, 2, and the control, respectively. Statistically, significant higher new bone formation was evident in the groups 1 and 2 as compared to the control group (p < 0.01). However, these differences were no more discernable after 12 weeks of healing. The results of the present investigation showed excellent in vivo biocompatibility but insufficient biodegrada‐ tion of the iCaP in the center of the defect area. Further attempts are required to expedite the biodegradation of the iCaP.