Stability Development of Immediately Loaded Hybrid Self-Tapping Implants Inserted in the Posterior Maxilla: 1-Year Results of a Randomized Controlled Trial.

The objective of the present study was to elucidate stability development of immediately loaded hybrid self-tapping implants inserted in the posterior maxilla. Forty-eight hybrid self-tapping implants with a chemically modified surface (∅4.1; length: 8 mm) were inserted bilaterally in the maxillary first and second premolar and first molar sites of 8 patients. In each patient, both sides of the maxilla were assigned randomly to either immediate (IL) or early (EL) loading group. Implant stability was evaluated by means of resonance frequency analysis immediately after implant placement and after 1, 2, 3, 4, 5, 6, 12, 26, and 52 weeks. High values of primary stability were found in both groups (71.91 ± 6.52 implant stability quotient [ISQ] in IL group; 73.87 ± 6.5 ISQ in EL group), with significant differences between the groups at the different time points. Initial decrease in stability was observed between the first and fifth weeks in the IL group and between the first and third weeks for the EL group. In the IL group 1 implant was removed after 3 weeks due to lack of stability. Early results of this study showed the ability of hybrid self-tapping dental implants with a chemically modified surface to achieve sufficient primary stability and to maintain high values of secondary implant stability in bone type 3 and 4, even when loaded immediately. Minimal alterations in stability were observed for both investigated groups, but the EL group showed faster recovery after an initial drop in stability.

Efficacy of fentanyl transdermal patch in pain control after lower third molar surgery: A preliminary study

BACKGROUND: Surgical removal of impacted lower third molars is a common oral surgical procedure, generally followed by moderate to severe postoperative pain. Transdermal drug delivery as a concept offers interesting possibilities for postoperative pain control. The aim of this study was to evaluate the efficacy of transdermal system with fentanyl in relieving pain following impacted lower third molar surgery. MATERIAL AND METHODS: Seventeen patients with bilateral impacted lower third molars were included in this preliminary study. For postoperative pain control, patients randomly received a fentanyl patch plus placebo tablet after the first operation and regular (placebo) patch and an analgesic, after the second operation. Analgesia was evaluated during first 24 hours postoperatively according to patients' reports about time of first pain appearance and additional analgesic consumption. Pain severity was rated using a 10 cm long visual analogue scale (VAS). RESULTS: Intensity of postoperative pain and postoperative analgesic consumption were significantly lower after the Fentanyl Transdermal System (FTS) was applied (p < 0.05). Duration of postoperative analgesia was significantly higher with FTS when compared to control treatment (p < 0.05). CONCLUSIONS: Based on the results of this preliminary study, transdermal system with fentanyl significantly reduced postoperative pain after third molar surgery

Correlation of bone vascularity in the posterior mandible and subsequent implant stability: a preliminary study.

OBJECTIVES: Bone vascularity is an important factor in process of osseointegration. The aim of this study was to find whether or not blood perfusion of the bone around the prepared implant sites influences subsequent implant stability. METHODS: Patients with bilaterally edentulous mandible were treated with dental implants. Bone vascularity in implant sites was previously noted using Laser Doppler Flowmetry (LDF). Implant stability quotient (ISQ) was measured during follow-up period of 26th week. Statistical distribution and correlation between LDF and ISQ values were presented. Other variables (type of implant loading; sex and distance from the apical part of implant sites to the roof of the mandibular canal) were collected and correlated with LDF values. RESULTS: The mean recorded LDF value was 53.05 perfusion unit. Eighteen implants were immediately loaded, and the other 18 were early loaded. In the group of early loaded implants, a statistically significant correlation between mean value of LDF and changing value of resonance frequency analysis (P < 0.05) was noted at 5th, 6th, 12th, and 26th weeks. Using Pearson coefficient of correlation, there was no statistically significant relationship between other variables and LDF values. CONCLUSION: LDF values of implant sites might determine future implant stability.

Immediate vs. early loading of SLA implants in the posterior mandible: 5-year results of randomized controlled clinical trial.

OBJECTIVES: The aim of this study was to compare clinical results of immediate and early loading (EL) self-tapping implants placed in posterior mandibles. MATERIAL AND METHODS: Twelve patients with bilateral edentulous posterior mandibular were randomly assigned to treatment either with immediate (test) or early loaded implants (control). Seventy-two self-tapping implants with SLA surface (Ø 4, 1/4, 8 mm; length 8 and 10 mm) were analyzed in this study. Test implants (36) were loaded on the day of surgery and control implants 6 weeks later. The measuring of implant stability quotient (ISQ) was performed on 0, 6th, 12th, and 52nd week after implant insertion. The bone resorption, modified plaque, and bleeding index were notified at 1 and 5 years later. RESULTS: After 5 years, survival in the both groups was 100%. The mean value of primary implant stability was 76.92 ± 0.79 ISQ. In the first 6 weeks, ISQ values significantly increased in the test group (77.92 ± 1.16 vs. 79.61 ± 0.90) as well as in the control group (7.92 ± 1.05 vs. 77.55 ± 0.99). A significant longitudinal increase in ISQ value was recorded in test and control group. The differences between immediate and early loaded implants were statistically insignificant (P > 0.05). At the 5 years, no statistically significant differences were found between immediate and early loaded implants with respect to mean crestal bone loss measurements (0.4 ± 0.24 vs. 0.8 ± 0.15 mm), mean bleeding index (0.22 ± 0.11 vs. 0.25 ± 0.11), and mean plaque index (0.17 ± 0.15 vs. 0.19 ± 0.20). CONCLUSION: Based on these results, the self-tapping implants inserted in posterior mandible can provide adequate primary stability value as the main factor for immediate and EL protocol.

Preimplantation filling of tooth socket with beta-tricalcium phosphate/polylactic-polyglycolic acid (beta-TCP/PLGA) root analogue: clinical and histological analysis in a patient.

INTRODUCTION: Bone resorption is a physiological process after tooth extraction. The use of bone substitutes to fill the tooth socket is suggested to prevent bone resorption and establish good bone architecture for implant placement. A pure beta-tricalcium phosphate coated with copolymer (polylactic-polyglycolic acid) as a root analogue, is suitable for filling tooth sockets. CASE REPORT: We presented a patient successfully treated with root analogue after extraction of the right second lower premolar. Three months later, the patient was planned for the placement of six TE ITI dental implants into the mandible. During the sugery, the biopsy of bone-like tissue from the previously treated socket was taken. All the implants were immediately loaded due to good primary stability. Histological analysis of the specimen revealed fibrous healing in the area treated with root analogue. CONCLUSION: The use of beta-tricalcium phosphate coated with copolymers after tooth extraction enables satisfactory bone architecture for consequent implant treatment.

Guided bone regeneration with a synthetic biodegradable membrane: a comparative study in dogs.

OBJECTIVES: The aim of the present study was to compare a newly developed biodegradable polylactide/polyglycolide/N-methyl-2-pyrrolidone (PLGA/NMP) membrane with a standard resorbable collagen membrane (RCM) in combination with and without the use of a bone substitute material (deproteinized bovine bone mineral [DBBM]) looking at the proposed tenting effect and bone regeneration. MATERIALS AND METHODS: In five adult German sheepdogs, the mandibular premolars P2, P3, P4, and the molar M1 were bilaterally extracted creating two bony defects on each site. A total of 20 dental implants were inserted and allocated to four different treatment modalities within each dog: PLGA/NMP membrane only (Test 1), PLGA/NMP membrane with DBBM (Test 2), RCM only (negative control), and RCM with DBBM (positive control). A histomorphometric analysis was performed 12 weeks after implantation. For statistical analysis, a Friedman test and subsequently a Wilcoxon signed ranks test were applied. RESULTS: In four out of five PLGA/NMP membrane-treated defects, the membranes had broken into pieces without the support of DBBM. This led to a worse outcome than in the RCM group. In combination with DBBM, both membranes revealed similar amounts of area of bone regeneration and bone-to-implant contact without significant differences. On the level of the third implant thread, the PLGA/NMP membrane induced more horizontal bone formation beyond the graft than the RCM. CONCLUSION: The newly developed PLGA/NMP membrane performs equally well as the RCM when applied in combination with DBBM. Without bone substitute material, the PLGA/NMP membrane performed worse than the RCM in challenging defects, and therefore, a combination with a bone substitute material is recommended.

The closure of oroantral communications with resorbable PLGA-coated beta-TCP root analogs, hemostatic gauze, or buccal flaps: a prospective study.

OBJECTIVE: The aim of this study was to compare the treatment of oroantral communications (OACs) with bioresorbable root analogs made of poly(lactide-co-glycolide) (PLGA)-coated beta-tricalcium phosphate (beta-TCP), hemostatic gauze or a buccal flap technique. STUDY DESIGN: In this prospective clinical study, 30 patients with oroantral communications were randomly assigned to a treatment. Clinical success, vestibular depth at the defect site, pain, and swelling were monitored. RESULTS: The OAC closure was successful in all cases. The vestibular depth stayed constant in the groups treated with the PLGA-beta-TCP composite or hemostatic gauze. In contrast, a vestibular depth reduction of 1.2 +/- 0.2 mm was observed in the buccal flap group, indicating atrophy of the alveolar ridge in these patients. Furthermore, pain and swelling were more pronounced in this group. CONCLUSION: Closures of OACs with PLGA-beta-TCP composite or hemostatic gauze are reliable minimally invasive methods that minimize atrophy of the alveolar ridge, swelling, and pain compared with a buccal flap technique.

Bone regeneration using a synthetic matrix containing a parathyroid hormone peptide combined with a grafting material.

PURPOSE: The aim of the present study was to test whether a newly developed synthetic matrix made of polyethylene-glycol (PEG) containing a covalently bound peptide of the parathyroid hormone (PTH1-34) enhances bone regeneration compared to grafting procedures and to spontaneous healing. MATERIALS AND METHODS: In each of 16 rabbits used, 4 titanium cylinders were screwed into perforated slits made in the cortical bone of the calvaria. The cylinders were either left empty (control) or filled with 1 of the following: (1) PEG matrix and hydroxyapatite/tricalcium phosphate (HA/TCP) granules, (2) PEG matrix containing 100microg/mL of PTH and HA/TCP granules, or (3) PEG matrix containing 20microg/mL of PTH1-34 and HA/TCP granules. After 8 weeks, the animals were sacrificed, and ground sections were obtained for histology. RESULTS: Quantitative histomorphometry demonstrated a significantly increased amount of newly formed bone for PTH1-34 compared to sites treated with PEG and HA/TCP and to empty control sites (P < .01; analysis of variance and subsequent pairwise Student t test). The mean percentages of mineralized bone were 19.6%+/-6.0% for 100 microg/mL PTH, 18.0% +/- 6.2% for 20microg/mL PTH, 12.0% +/-6.5% for PEG and HA/TCP without PTH, and 10.5% +/-3.7% for the empty control. The mean areas of bone regenerated within the cylinders were 53.5% +/-22.7% for 100 microg/mL PTH, 51.1% +/-22.6% for 20 microg/mL PTH, 34.3% +/- 22.5% for PEG and HA/TCP without PTH, and 23.2% +/-10.1% for the empty control. DISCUSSION: Human and animal trials have demonstrated that daily systemic injection of PTH increases bone mineral density. The present study showed that local administration of PTH was also effective in stimulating bone formation. CONCLUSION: It is concluded that this synthetic PEG hydrogel containing a covalently bound peptide of the PTH combined with HA/TCP granules significantly stimulated in situ bone augmentation in rabbits.

[Influence of the myocardial bridging phenomenon on the myocardial structure and the coronary arteries wall structure changes].

BACKGROUND/AIM: Our research was performed to evaluate the influences of the myocardial bridgings of coronary arteries on the myocardial and coronary arteries wall structure chages, that could be a reason for multiple heart malfunctions. METHODS: We analyzed the autopsy material, collected during a five-years period, and especially the group of 575 cases with the major aim to diagnose mors naturalis. In all cases with the presence of myocardial bridge over the arterial coronary wall revealed at autopsy, samples were taken for microscopic verification and examination. RESULTS: We found myocardial bridges over the coronary arteries or their major branches in 27 of the cases (4.70%). We believe that myocardial bridges compromise coronary perfusion by cyclic compression of the overbridged vessels, and that it could be the initial factor in the pathogenesis of arteriosclerotic degeneration processes on the coronary artery wall. We found different grades of arteriosclerotic changes in 88.89% of the cases, as well as fibrosis of myocardium in 88.89% and lipomatosis in 66.67% of the cases with the present myocardial bridges. CONCLUSION: Our results suggested that myocardial bridging of coronary arteries and/or their branches was the pathological and even lethal phenomenon that de serves more intensive clinical evaluation.

Platelet-rich plasma and fibrin as delivery systems for recombinant human bone morphogenetic protein-2.

The aim of the present study was (1) to test whether or not platelet-rich plasma (PRP) or commercially available fibrin can increase bone regeneration compared with non-treated defects and (2) to test whether or not PRP or fibrin increases bone regeneration when used as a delivery system for recombinant human bone morphogenetic protein-2 (rhBMP-2). In 16 New Zealand White rabbits, four evenly distributed 6 mm diameter defects were drilled into the calvarial bone. The following five treatment modalities were randomly allocated to all 64 defects: (0) untreated control, (1) fibrin alone, (2) PRP alone, (3) fibrin with 15 microg rhBMP-2 and (4) PRP with 15 microg rhBMP-2. For the fibrin gels and the PRP containing rhBMP-2, the 15 microg rhBMP-2 was incorporated by precipitation within the matrices before their gelation. After 4 weeks, the animals were sacrificed and the calvarial bones were removed for histological preparation. The area fraction of newly formed bone was determined in vertical sections from the middle of the defect by applying histomorphometrical analysis. A mean area fraction of newly formed bone was found within the former defect of 23.4% (+/-13.5%) in the control sites, of 28.4% (+/-17.4%) in the fibrin sites and of 34.5% (+/-17.4%) in the PRP sites. The statistical analysis revealed no significant difference in bone formation between the three groups (ANOVA). Addition of 15 microg rhBMP-2 in the fibrin gel (59.9+/-20.3%) and the PRP gels (63.1+/-25.3%) increased bone formation significantly. No significant difference was observed between sites, where PRP or fibrin has been used as a delivery system for rhBMP-2 (ANOVA). In conclusion, the application of fibrin gels or PRP gels to bone defects is not superior to leaving the defect untreated. Regarding the amount of bone formation, the application of 15 microg rhBMP-2 in bone defects enhances the healing significantly at 4 weeks. In this animal model, commercially available fibrin and autologous PRP gels are equally effective as delivery systems for rhBMP-2.