Thomas Jensen

Maxillary sinus floor augmentation with Bio-Oss or Bio-Oss mixed with autogenous bone as graft: a systematic review.

AIMS The objective of the present systematic review was to test the hypothesis of no differences in the implant treatment outcome when Bio-Oss or Bio-Oss mixed with autogenous bone is used as graft for the maxillary sinus floor augmentation (MSFA) applying the lateral window technique. MATERIAL AND METHODS A MEDLINE (PubMed) search in combination with a hand search of relevant journals was conducted by including human studies published in English from January 1, 1990 to June 1, 2010. The search provided 879 titles and 35 studies fulfilled the inclusion criteria. Considerable variation in the included studies prevented meta-analysis from being performed and no long-term study comparing MSFA with the two treatment modalities was identified. Also, the survival of suprastructures after the two augmentation procedures was not compared within the same study. RESULTS The 1-year implant survival was compared in one study demonstrating no statistically significant difference. The implant survival was 96% with Bio-Oss and 94% with a mixture of 80% Bio-Oss and 20% autogenous mandibular bone. Addition of a limited amount of autogenous bone to Bio-Oss seemed not to increase the amount of new bone formation and bone-to-implant contact compared with Bio-Oss. CONCLUSIONS Therefore, the hypothesis of no differences between the use of Bio-Oss or Bio-Oss mixed with autogenous bone as graft for MSFA could neither be confirmed nor rejected.

Volumetric changes of the graft after maxillary sinus floor augmentation with Bio-Oss and autogenous bone in different ratios: a radiographic study in minipigs

OBJECTIVE The objective of the present study was to learn about the volumetric changes of the graft after maxillary sinus floor augmentation with Bio-Oss and autogenous bone from the iliac crest or the mandible in different ratios in minipigs. MATERIAL AND METHODS Bilateral maxillary sinus floor augmentation was performed in 40 minipigs with: (A) 100% autogenous bone, (B) 75% autogenous bone and 25% Bio-Oss, (C) 50% autogenous bone and 50% Bio-Oss, (D) 25% autogenous bone and 75% Bio-Oss, and (E) 100% Bio-Oss. The autogenous bone graft was harvested from the iliac crest or the mandible and the graft composition was selected at random and placed concomitant with implant placement. Computed tomographies of the maxillary sinuses were obtained preoperatively, immediately postoperatively, and at euthanasia after 12 weeks. The volumetric changes of the graft were estimated using the Cavalieri principle and expressed as mean percentage with a 95% confidence interval (CI). RESULTS The mean volume of the graft was reduced by (A) 65% (95% CI: 60-70%), (B) 38% (95% CI: 35-41%), (C) 23% (95% CI: 21-25%), (D) 16% (95% CI: 12-21%), and (E) 6% (95% CI: 4-8%). The volumetric reduction was significantly influenced by the ratio of Bio-Oss and autogenous bone (P<0.001), but not by the origin of the autogenous bone graft (P=0.2). CONCLUSIONS The volume of autogenous bone grafts from the iliac crest and the mandible is reduced significantly after maxillary sinus floor augmentation in minipigs. The graft volume is better preserved after the addition of Bio-Oss and the volumetric reduction is significantly influenced by the ratio of Bio-Oss and autogenous bone. However, further studies are needed addressing the amount of new bone formation and bone-to-implant contact before the final conclusion can be made about the optimal ratio of Bio-Oss and autogenous bone.

Comparison of Degrees of Left Ventricular Dilation Within Three Hours and Up to Six Days After Onset of First Acute Myocardial Infarction

Following an acute myocardial infarction (AMI) there is immediate deterioration of contractility in the infarcted left ventricular (LV) wall. This can be followed by regional dilation (expansion) as well as global remodeling. We examined 35 consecutive patients--with no history of myocardial ischemia--who were admitted to hospital within 3 hours after initial symptoms and with ST-segment changes on an electrocardiogram consistent with transmural ischemia. Echocardiography was performed at admission, and at 6 hours, 12 hours, 24 hours, 3 days, and 6 days after onset of the AMI. Within 3 hours after onset of symptoms an increase in both end-diastolic volume index (EDVI) and end-systolic volume index (ESVI) was found in both anterior and inferior infarcts when compared with healthy controls (mean +/- SD EDVI: 99 +/- 13 ml/m2 [anterior], 69 +/- 17 ml/m2 [inferior], 51 +/- 15 ml/m2 [controls], p < or = 0.00001; ESVI: 62 +/- 12 ml/m2 [anterior], 38 +/- 11 ml/m2 [inferior], 17 +/- 6 ml/m2 [controls], p < or = 0.00001). At all points in time, volumes were larger in anterior infarcts than in inferior infarcts (p < 0.05). The volumes did not change during the 6 days (p > 0.1). Thus, major LV dilation is present within 3 hours after onset of symptoms of first AMI. The dilation is more pronounced in anterior versus inferior infarcts. From 3 hours until day 6 no further changes in LV volumes occurred.

The effect on bone growth enhancement of implant coatings with hydroxyapatite and collagen deposited electrochemically and by plasma spray.

Skeletal bone consists of hydroxyapatite (HA) [Ca(10)(PO(4))(6)(OH)(2)] and collagen type I, both of which are osseoconductive. The goal of osseointegration of orthopedic and dental implants is the rapid achievement of a mechanically stable long-lasting fixation between bone and an implant surface. In this study, we evaluated the mechanical fixation and tissue distribution surrounding implants coated with three surfaces: plasma-sprayed HA coating, thinner coating of electrochemical-assisted deposition of HA, and an identical thin coating with a top layer of mineralized collagen. Uncoated plasma-sprayed titanium (Ti-6Al-4V) served as negative control. The electrochemical-assisted deposition was performed near physiological conditions. We used a canine experimental joint replacement model with four cylindrical implants (one of each treatment group) inserted in the humeri cancellous metaphyseal bone in a 1 mm gap. Observation time was 4 weeks. The mechanical fixation was quantified by push-out test to failure, and the peri-implant tissue formation by histomorphometric evaluation. HA coatings deposited by plasma spray technique or electrochemically, increased the mechanical fixation and bone ongrowth, but there was no statistical difference between the individual HA applications. Addition of collagen to the mineralized phase of the coating to create a more bone natural surface did not improve the osseoconductive effect of HA.

Maxillary sinus floor augmentation with Bio-Oss or Bio-Oss mixed with autogenous bone as graft in animals: a systematic review

The objective of the present systematic review was to test the hypothesis of no differences between the use of Bio-Oss or Bio-Oss mixed with autogenous bone as graft for maxillary sinus floor augmentation (MSFA) applying the lateral window technique, as evaluated in animals. A MEDLINE (PubMed), Embase, and Cochrane Library search in combination with a hand-search of relevant journals was conducted by including animal studies published in English from 1 January 1990 to 1 June 2010. The search provided 879 titles and 14 studies fulfilled the inclusion criteria. The volumetric stability of the graft improved significantly with increased proportion of Bio-Oss. Bone regeneration, bone-to-implant contact (BIC), biomechanical implant test values, and biodegradation of Bio-Oss after MSFA with Bio-Oss or Bio-Oss mixed with autogenous bone have never been compared within the same study in animals. Thus, the hypothesis of no differences between the use of Bio-Oss and Bio-Oss mixed with autogenous bone as graft for MSFA could neither be confirmed nor rejected based on existing animal studies.

Donor Site Morbidity Associated With Autogenous Bone Harvesting From the Ascending Mandibular Ramus

Purpose:The objective of the present retrospective study was to assess long-term morbidity and postoperative complications after autogenous bone harvesting from the ascending mandibular ramus. Materials and Methods:Bone harvesting from the ascending mandibular ramus was conducted in a consecutive case series, including 325 patients, at The Department of Oral and Maxillofacial Surgery, Aalborg University Hospital, Denmark from January 1, 2000 to December 31, 2010. Records and radiographs were retrospectively analyzed. Results:Temporary neurosensory disturbances in the inferior alveolar nerve were found in 6.1% of the patients. Only 0.5% of the patients had permanent neurosensory disturbances. Severe hematoma occurred in 20 patients, while infection occurred in only 1 patient. Conclusions:Within the limitations of a retrospective case series study, the present study suggests that harvesting of autogenous bone from the ascending mandibular ramus is a safe surgical procedure with minimal donor site morbidity and few postoperative complications.

Local delivery of zoledronate from a poly (D,L-lactide)-Coating increases fixation of press-fit implants.

Early secure fixation of total joint replacements is crucial for long‐term survival. Antiresorptive agents such as bisphosphonates have been shown to increase implant fixation. We investigated whether local delivery of zoledronate from poly‐D, L‐lactide (PDLLA)‐coated implants could improve implant fixation and osseointegration. Experimental titanium implants were bilaterally inserted press‐fit into the proximal tibiae of 10 dogs. On one side the implant was coated with PDLLA containing zoledronate. The contralateral implant was uncoated and used as control. Observation period was 12 weeks. Implant fixation was evaluated with histomorphometry and biomechanical push‐out test. We found an approximately twofold increase in all biomechanical parameters when comparing data from the zoledronate group with their respective controls. Histomorphometry showed increased amount of preserved bone and increased bone formation around the zoledronate implants. This study indicates that local delivery of zoledronate from a PDDLA coating has the potential to increase implant fixation.

Lateral ridge augmentation with Bio-Oss alone or Bio-Oss mixed with particulate autogenous bone graft: a systematic review

The objective of this systematic review was to test the hypothesis of no difference in implant treatment outcomes when using Bio-Oss alone or Bio-Oss mixed with particulate autogenous bone grafts for lateral ridge augmentation. A search of the MEDLINE, Cochrane Library, and Embase databases in combination with a hand-search of relevant journals was conducted. Human studies published in English from 1 January 1990 to 1 May 2016 were included. The search provided 337 titles and six studies fulfilled the inclusion criteria. Considerable variation prevented a meta-analysis from being performed. The two treatment modalities have never been compared within the same study. Non-comparative studies demonstrated a 3-year implant survival of 96% with 50% Bio-Oss mixed with 50% autogenous bone graft. Moreover, Bio-Oss alone or Bio-Oss mixed with autogenous bone graft seems to increase the amount of newly formed bone as well as the width of the alveolar process. Within the limitations of this systematic review, lateral ridge augmentation with Bio-Oss alone or in combination with autogenous bone graft seems to induce newly formed bone and increase the width of the alveolar process, with high short-term implant survival. However, long-term studies comparing the two treatment modalities are needed before final conclusions can be drawn.

Topical bisphosphonate augments fixation of bone-grafted hydroxyapatite coated implants, BMP-2 causes resorption-based decrease in bone

Bone allograft is used in total joint arthroplasties in order to enhance implant fixation. BMPs are known to stimulate new bone formation within allograft, but also known to accelerate graft resorption. Bisphosphonates are strong inhibitor of bone resorption. The aim of this study was to investigate whether the bisphosphonate zoledronate was able to counteract the accelerated graft resorption without interfering with the BMP induced bone formation. In the present study the two drugs alone and in combination were studied in our canine model of impaction bone grafting. We included 10 dogs in this study. Cancellous allograft bone grafts were soaked in either saline or zoledronate solution (0.005mg/mL) and then vehicle or BMP2 (0.15mg rhBMP2) was added. This produced four treatment groups: A) control, B) BMP2, C) zoledronate and D) BMP2+zoledronate. The allograft treated with A, B, C or D was impacted into a circumferential defect of 2.5mm around HA-coated porous Ti implants. Each dog received all four treatment groups with two implants in the distal part of each femur. The group with allograft soaked in zoledronate (C) showed better biomechanical fixation than all other groups (p<0.05). It had less allograft resorption compared to all other groups (p<0.005) without any statistically significant change in new bone formation. The addition of BMP2 to the allograft did not increase new bone formation significantly, but did accelerate allograft resorption. This was also the case where the allograft was treated with BMP2 and zoledronate in combination (D). This caused a decrease in mechanical implant fixation in both these groups compared to the control group, however only statistically significant for the BMP2 group compared to control. The study shows that topical zoledronate can be a valuable tool for augmenting bone grafts when administered optimally. The use of BMP2 in bone grafting procedures seems associated with a high risk of bone resorption and mechanical weakening.

Local delivery of zoledronate from a poly (D,L-lactide)-coating increases fixation of hydroxy-coated implants.

Initial secure implant fixation predicts long‐term survival. Bisphosphonates are anti‐resorptive agents. They have been shown to increase implant fixation. We investigated whether local delivery of zoledronate from a poly‐d,l‐lactide (PDLLA)‐coating could improve fixation and osseointegration of hydroxy‐apatite coated implants. Cylindrical hydroxy‐apatite coated implants were bilaterally inserted press‐fit into the proximal tibiae of 10 dogs. On one side the implant was coated with PDLLA containing zoledronate. The PDLLA coating was applied upon the hydroxy‐apatite coating. We used the contralateral implant as control. This implant was not coated with a poly‐d,l‐lactide. Observation period was 12 weeks. We evaluated implant fixation with histomorphometry and biomechanical push‐out test. Zoledronate resulted in an approximately threefold increase in all biomechanical parameters when comparing data with their respective controls. We found that zoledronate increased preservation of old lamellar bone and increased formation of new woven bone. This study indicates that local delivery of zoledronate from a PDDLA coating has the potential to increase implant fixation. Studies investigating different doses of zoledronate and longer follow‐up are needed.