Effect of Diclofenac and Simvastatin on Bone Defect Healing-An In Vivo Animal Study.

Non-steroidal, anti-inflammatory drugs and statins are two widely prescribed drug classes that affect bone formation. The aim of this study was to elucidate the effect of diclofenac and simvastatin in artificial bone defect healing. One hundred and forty-four male Wistar rats were used, and the specimens were divided into groups, with respect to the route of drug administration and the type of defect healing (with or without collagen membrane), and subgroups, with respect to the study duration (2, 4 or 8 weeks). Diclofenac was intramuscularly administered while simvastatin was administered both systemically and locally. Animals were euthanized and specimens were histomorphometrically analyzed to evaluate the percentage of new bone formation (%). Bone healing that occurred without any intervention developed more steadily than that of all other groups. Diclofenac exerted a clear, direct inhibitory effect on bone healing and its systemic administration should be avoided. The systemic administration of simvastatin was related to severe myopathy, while the solvent for the local administration of simvastatin seemed to play significant role in bone growth, as simvastatin, when it is administered intraperitoneally in a DMSO solution, appeared to promote bone healing. Local administration may have a significant impact on bone healing and it should be further investigated with the type of solvent or carrier that is used, which both may play a significant role in bone repair induction.

Alveolar ridge alterations in the maxillary anterior region after tooth extraction through orthodontic forced eruption for implant site development: a clinical CBCT study.

OBJECTIVE: To investigate the effects of orthodontic forced eruption (OFE) with the straight-wire appliance in the dimensions of the alveolar process when used for extracting compromised maxillary anterior teeth and implant site development. MATERIAL AND METHODS: Cone-beam computed tomography (CBCT) scans of 7 patients needing extraction of 17 maxillary anterior teeth were obtained before and immediately after OFE. Alveolar plate height and thickness measurements were performed on the buccal and palatal socket walls in CBCT sagittal cross sections. Statistical analysis included sample size calculation, paired t-test, and Wilcoxon test to evaluate alveolar plate dimensional changes and linear regression analysis to assess whether bone changes and the feasibility of implant insertion were associated to tooth type and root length, baseline alveolar plate thickness, and age. RESULTS: OFE caused statistically significant reduction of the buccal alveolar plate height (1.95 ± 1.83 mm) and significant increase of the palatal alveolar plate height (1.31 ± 2.41 mm) in the central tooth socket areas. Buccal reduction was associated positively to the baseline root length and negatively to the thickness of the corresponding plate in the apical level. A non-significant increase was noted in both buccal (0.23 ± 0.93 mm) and palatal (0.63 ± 1.59 mm) proximal bone. Inadequate buccal bone support hindered immediate implant placement in six sockets; however, all inserted implants showed adequate and gradually increasing stability from insertion to final restoration. CONCLUSIONS: OFE resulted in favourable increase in the heights of the palatal and proximal alveolar bone and significant reduction in the buccal plate height, which inhibited implant placement in 35% of the treated sockets.

Effect of clopidogrel in bone healing-experimental study in rabbits.

BACKGROUND: Clopidogrel is a widely prescribed drug for prevention of myocardial infarction and stroke in patients at risk. It inhibits thrombus formation via inhibition of the P2Y12 purinergic receptor on platelets, which is important in their activation by ADP. However, the P2Y12 receptor has also been found to be expressed in both osteoblasts and osteoclasts. Accumulated evidence suggests that purinergic receptors regulate important functions of bone turnover. Previous studies on the effect of clopidogrel on bone metabolism indicated potential harmful effects, but their results remain conflicting. Thus, clopidogrel treatment may affect bone healing, but it has not yet been studied. AIM: To evaluate if continuous perioperative clopidogrel treatment has any negative effect on bone healing in the rabbit calvarial defect model. METHODS: Sixteen male white New Zealand rabbits were randomly assigned in two groups: One group received daily 3 mg/kg of clopidogrel per os and the other group received the vehicle alone for a week prior to the surgical procedures; the treatments were continued for another 6 wk postoperatively. The surgical procedures included generation of two circular calvarial defects 11 mm in diameter in every animal. After the 6-wk period of healing, postmortem radiographic and histomorphometric evaluation of the defects was performed. RESULTS: Both the surgical procedures and the postoperative period were uneventful and well tolerated by all the animals, without any surgical wound dehiscence, signs of infection or other complication. New bone was formed either inwards from the defect margins or in the central portion of the defect as separated bony islets. While defect healing was still incomplete in both groups, the clopidogrel group had significantly improved radiographic healing scores. Moreover, the histomorphometric analysis showed that bone regeneration (%) was 28.07 ± 7.7 for the clopidogrel group and 19.47 ± 4.9 for the control group, showing a statistically significant difference between them (P = 0.018). Statistically significant difference was also found in the defect bridging (%), i.e. 72.17 ± 21.2 for the clopidogrel group and 41.17 ± 8.5 for the control group, respectively (P = 0.004), whereas there was no statistical difference in bone tissue density between the groups. CONCLUSION: Our results indicate that maintenance of perioperative clopidogrel treatment does not negatively affect bone healing but rather promotes it. Further research is needed in order to find useful applications of this finding.

Safety of dental extractions during uninterrupted single or dual antiplatelet treatment.

Optimal dental management in patients on long-term antiplatelet treatment is not clearly defined. Antiplatelet discontinuation increases the risk of thrombotic complications, whereas uninterrupted antiplatelet therapy, which is the currently recommended approach, is assumed to increase the bleeding hazard after dental procedures. We sought to prospectively compare the risk of immediate and late postextraction bleeding in patients receiving uninterrupted single or dual antiplatelet therapy. We recruited 643 consecutive patients referred for dental extractions. In total 111 (17.3%) were on clinically indicated antiplatelet therapy: aspirin (n = 42), clopidogrel (n = 36), and aspirin and clopidogrel (n = 33). Controls (n = 532, 82.7%) were not on antiplatelet treatment. Immediate and late bleeding complications were recorded. Compared to controls the risk of prolonged immediate bleeding was higher in patients on dual antiplatelet therapy (relative risk [RR] 177.3, 95% confidence interval [CI] 43.5 to 722, p <0.001) but not in patients on aspirin alone (RR = 6.3, 95% CI 0.6 to 68.4, p = 0.2) or clopidogrel alone (RR = 7.4, 95% CI 0.7 to 79.5, p = 0.18); however, all immediate bleeding complications in all treatment groups were successfully managed with local hemostatic measures. No patient developed any late hemorrhage. In conclusion, dental extractions may be safely performed in patients receiving single or dual antiplatelet therapy when appropriate local hemostatic measures are taken, thus averting thrombotic risk of temporary antiplatelet discontinuation.

Incidence of impacted and supernumerary teeth–a radiographicstudy in a North Greek population

Objectives: The aim of the present study was to investigate the prevalence of impacted and supernumerary teeth,apart from third molars. Study design: This was a retrospective study of 1.239 panoramic radiographs taken of patients who presented tothe Department of Dentoalveolar Surgery, Implantology and Radiology at the School of Dentistry of the Aristotle University of Thessaloniki, Greece between 1991 and 1999. The panoramic radiographs and dental records were reviewed in order to determine whether there were impacted or supernumerary teeth. Observations were also made on the space in dentition, corresponding to the position of each impacted tooth, the lack of space for tootheruption, transmigration, retained primary teeth or prosthetic restoration. Results: A total of 170 (13.7%) patients presented with at least one impacted tooth. None of them had an impactedincisor. Impacted canines were the most prevalent dental anomaly (8.8%), followed by impacted premolars (2.2%).Supernumerary teeth (1.8%) and impacted molars (1%) were the least common anomalies. Among the 225 impacted teeth, the most frequently affected teeth were the canines (59.6%), followed by premolars (19.1%), and supernumerary teeth (15.1%), while the incidence of impacted molars was substantially lower (6.2%). Conclusions: The most frequently impacted teeth were the maxillary canine, the second mandibular premolarand the second mandibular molar. The majority of the supernumerary teeth consisted of mesiodens. There was space in the dentition of each impacted tooth in 29.3% of the cases examined; there was a retained primary toothin 25.1%, and a prosthetic restoration had been constructed in 24%. Insufficient space for the eruption of the impactedtooth and transmigration was observed in 17.3% and 4.2% of the cases, respectively (AU)

Incidence of impacted and supernumerary teeth-a radiographic study in a North Greek population.

OBJECTIVES: The aim of the present study was to investigate the prevalence of impacted and supernumerary teeth, apart from third molars. STUDY DESIGN: This was a retrospective study of 1.239 panoramic radiographs taken of patients who presented to the Department of Dentoalveolar Surgery, Implantology and Radiology at the School of Dentistry of the Aristotle University of Thessaloniki, Greece between 1991 and 1999. The panoramic radiographs and dental records were reviewed in order to determine whether there were impacted or supernumerary teeth. Observations were also made on the space in dentition, corresponding to the position of each impacted tooth, the lack of space for tooth eruption, transmigration, retained primary teeth or prosthetic restoration. RESULTS: A total of 170 (13.7%) patients presented with at least one impacted tooth. None of them had an impacted incisor. Impacted canines were the most prevalent dental anomaly (8.8%), followed by impacted premolars (2.2%). Supernumerary teeth (1.8%) and impacted molars (1%) were the least common anomalies. Among the 225 impacted teeth, the most frequently affected teeth were the canines (59.6%), followed by premolars (19.1%), and supernumerary teeth (15.1%), while the incidence of impacted molars was substantially lower (6.2%). CONCLUSIONS: The most frequently impacted teeth were the maxillary canine, the second mandibular premolar and the second mandibular molar. The majority of the supernumerary teeth consisted of mesiodens. There was space in the dentition of each impacted tooth in 29.3% of the cases examined; there was a retained primary tooth in 25.1%, and a prosthetic restoration had been constructed in 24%. Insufficient space for the eruption of the impacted tooth and transmigration was observed in 17.3% and 4.2% of the cases, respectively.

Evaluation of peri-implant marginal bone loss using modified abutment connections at various crestal level placements.

The purpose of this study was to evaluate crestal bone loss around 282 two-piece implants with straight (n = 193) and platform-switched (n = 89) abutment connections after placement at various crestal levels. Implants were assigned into two groups according to straight and platform-switched abutment connections. Each group was further subdivided into three groups depending on the location (supracrestal, crestal, or subcrestal) of the implant cervical platform. Linear measurements of bone resorption were made from the implant's platform to the first point of bone-to-implant contact at the time of implant placement and 2 years postrestoration. Data were statistically analyzed. Statistically significant differences were found between subgroups in both straight and platform-switched categories. The only nonstatistically significant difference (P = .341) arose when comparing the supra- and subcrestal locations in the straight abutment connection group. The platform-switched group exhibited significantly less bone loss (P = .046) only in subcrestal locations. The platform-switched concept was not beneficial during the overall comparison, but it was for the subcrestal location of the abutment connection. Crestal placement of the implant-abutment connection resulted in higher marginal bone resorption in both straight and platform-switched abutments.

Comparison of acceptance, preference, and efficacy between jet injection INJEX and local infiltration anesthesia in 6 to 11 year old dental patients.

Needleless devices have been developed to provide anesthesia without injections. Little controlled research has examined the acceptability of needleless devices in pediatric patients. The aims of the study were to compare children's acceptance and preference for one type of needleless jet injection with classical local infiltration as well as to evaluate the efficacy of the needleless anesthesia. Eighty-seven nonfearful children with no previous experience of dental anesthesia were studied using a split-mouth design. The first dental procedure was performed with the classical infiltration anesthesia. The same amount of anesthetic was administered using the INJEX needleless device in a second session 1 week later, during which a second dental procedure was performed. Patients rated their acceptance and preference for the 2 methods, and the dentist recorded data about the need for additional anesthesia. More negative experiences were reported for the INJEX method. Most (73.6%) of the children preferred the traditional method. Among the 87 treatment procedures attempted following the use of INJEX, 80.5% required additional anesthesia, compared with 2.3% of those attempted following traditional infiltration. Traditional infiltration was more effective, acceptable, and preferred, compared with the needleless INJEX.

A comparison of panoramic image quality between a digital radiography storage phosphor system and a film-based system.

AIM: To compare digital panoramic images acquired for the presurgical assessment of third molars captured with a storage phosphor-based system with conventional film panoramic radiographs. METHODS AND MATERIALS: A total of 51 pairs of digital and conventional panoramic images, made simultaneously, were included in this study. The images were evaluated for diagnostic quality prior to third molar surgery by two experienced oral surgeons and rated with a four-point grading scale. RESULTS: Despite the fact that conventional panoramic images were rated higher than the digital images, the difference was not statistically significant. CONCLUSIONS: Conventional and digital panoramic images were found to be of comparable image quality with regard to their diagnostic contribution to third molar surgery. CLINICAL SIGNIFICANCE: This study is contributory to understanding differences in image quality between digital and conventional panoramic radiography for certain diagnostic tasks. The lack of significant differences in image quality may be an endorsement for digital panoramic radiography.

Evaluation of the osteogenic potential in experimental defects, with and without bone marrow, in the rabbit tibia: a pilot study.

PURPOSE: The influence of bone marrow in the osteogenic potential of bone has not been evaluated in the rabbit tibia model. Previous studies employed this model extensively to test the osteogenic capabilities of bone grafts. The primary aim of the present study was to assess the role of bone marrow in the healing of experimental defects in the rabbit tibia model. MATERIALS AND METHODS: Ten New Zealand rabbits were divided into two groups of five each. In the first experimental test group (PoP), the marrow cavity was emptied completely under a 6-mm defect in the rabbit tibia metaphysis; the marrow was replaced by plaster of Paris, and a round piece of lyophilized collagen membrane was placed in contact with the endosteum and rested on the plaster. In the second experimental group (control), similar artificial defects were made, but the marrow was left intact. After 8 weeks, the animals were sacrificed and prepared for histologic and histomorphometric analysis. RESULTS: There was a statistically significant difference (P = .016) in newly formed bone area between the control group (mean, 68.08% +/- 12.09%) and the PoP group (mean, 54.02% +/- 13.93%). Similarly, there was a statistically significant difference in new bone density (P < .001) between the control group (mean, 95.99% +/- 1.74%) and the PoP group (mean, 75.37% +/- 13.27%). CONCLUSIONS: The current study confirms the significant effect that bone marrow has in bone regeneration and also the true regenerative capabilities of the osseous walls of the defects. The proposed experimental model may be a more reliable method of investigating and comparing the potential of different graft materials and methods.

Osseointegration of Osseotite and machined-surfaced titanium implants in membrane-covered critical-sized defects: a histologic and histometric study in dogs.

The texture of an implant's surface can influence the rate and extent of bone fixation as expressed by the amount of linear bone-to-implant contact (BIC). The purpose of this study was to compare the bone density and linear BIC between Osseotite and machined-surface implants placed in bony defects without graft material and covered by a membrane. Thirty 2 mm diameter, 10 mm length custom implants were prepared for this study having a 'split surface,' with one side having the acid-etched surface and the opposite side having a machined surface. Defects were created in the iliac wing of three adult mongrel dogs where a 6-mm-diameter drill was used to generate a 5-mm-deep defect. The implants were inserted into the center of the defect with 5 mm secured into the bone leaving 5 mm free in the defect with a 2 mm gap between the implant and surrounding bone. Expanded polytetrafluroethelyene membranes were placed over the defect sites stabilized with Biotack pins. The healing times were 2, 3, and 5 months. Histologic and histometric analysis showed significantly lower BIC in the defect region as compared with the portion of implant placed into native bone for both implant surfaces in all groups. There was no difference in BIC values at 2- and 5-month periods between the two surfaces in the regenerated area, while BIC values for Osseotite surfaces were significantly higher than the machined surfaces at 3 months' healing time. Changes in bone density, observed between the three groups, affected correspondingly the BIC values in both implant surfaces, the effect being more pronounced in the Osseotite surface.

Needle-less local anesthesia: clinical evaluation of the effectiveness of the jet anesthesia Injex in local anesthesia in dentistry.

OBJECTIVES: To clinically evaluate the jet injection Injex (Rösch AG Medizintechnik) using 2 different anesthetic solutions, and to compare the jet injection and the standard needle injection techniques. METHOD AND MATERIALS: Of the 32 patients in the study, 10 received mepivacaine 3% anesthetic solution by means of the jet injection technique, while the remaining 22 patients received lidocaine 2% with epinephrine 1:80,000 by the same method. The 14 patients in whom pulp anesthesia was achieved were selected for an additional evaluation of the pulp reaction using standard needle injection anesthesia. The differences between the 2 compounds with Injex were statistically evaluated by means of independent-samples t test analysis. The differences between subgroups receiving both jet injection and needle injection anesthesia were evaluated by means of paired t test analysis. RESULTS: The administration of mepivacaine 3% using Injex did not achieve pulp anesthesia in any of the 10 patients, although the soft tissue anesthesia was successful. The administration of lidocaine with epinephrine using Injex resulted in pulp anesthesia in only 14 patients; soft tissue anesthesia was observed in all patients of this group. There was no statistically significant difference between Injex and the needle injection technique in onset of anesthesia. However, the duration of anesthesia was significantly longer for the needle infiltration group than for the Injex injection group. CONCLUSION: The anesthetic solution should be combined with a vasoconstriction agent when the Injex technique is implemented.

Bone regeneration around implants using spherical and granular forms of bioactive glass particles.

PURPOSE: It has been reported that previous Biogran (3i Implant Innovations, Inc., Palm Beach Gardens, FL) can be converted in vitro into hydroxyapatite (Biogran II) to accelerate new bone formation. The purpose of this study was to evaluate the bone regeneration around implants placed in critical-sized defects in rabbit tibia using granular and spherical forms of Biogran II in regards to implant contact, bone-to-graft contact, bone graft area, and total bone volume. MATERIALS AND METHODS: Twelve adult New Zealand rabbits were used, offering 24 surgical sites (1 in each tibia), where 6-mm round defects were created allowing the homocentric insertion of a screw type experimental implant with Osseotite (3i Implant Innovations, Inc.) surface. Half of the defects (group A) were filled up with spherical and half (group B) with granular forms of Biogran II. Ossix (3i Implant Innovations, Inc.) membranes covered the surgical sites. RESULTS: The histological evaluation after 8 weeks showed new bone formation in both groups, without any statistically significant differences in regards to bone-to-implant contact, bone-to-graft contact, bone graft area, and bone volume. Both dissolution of the outer shell and inner silica gel of the particles were observed mostly in spherical particles. In addition, new bone formation within the protected pouch interconnected with the surrounding new bone was observed exclusively in spherical particles of Biogran II. CONCLUSION: Faster dissolution of both outer and inner portions of spherical particles of Biogran II led to better integration with the surrounding new bone during an 8-week period of healing.

The role of temperature in the action of mepivacaine.

The role of temperature in the action of local anesthetics was studied in 20 healthy young volunteers with plain 3% mepivacaine injected periapically twice in their maxillary first premolar, the first time with the solution at a temperature of 20 degrees C and the second time at 4 degrees C. The pulpal response was measured with a pulp tester every minute. The onset of pulp anesthesia was found to be of no statistical difference between 20 degrees C and 4 degrees C. On the other hand, mepivacaine at a temperature of 4 degrees C was found to have a statistically significant longer duration of action. Our conclusion is that the drop in temperature of mepivacaine from 20 degrees C to 4 degrees C provides a longer duration of pulpal anesthesia.

The role of temperature in the action of local anesthetics: a double study in vitro and in vivo.

The purpose of this study was the examination of the role of temperature in the action of lidocaine via electrophysiological recordings on the sciatic nerve of the rat in vitro and in vivo. 20 Male Wistar rats were used in each type of experiment. In vitro, lidocaine shows no statistically significant difference regarding the onset of anesthesia but at the temperature of 25 degrees C it is significantly more potent on the establishment of anesthesia compared to the temperature of 36.5 degrees C. In vivo, lidocaine at the temperature of 4 degrees C is statistically significantly more effective in the establishment and the duration of anesthesia related to the temperature of 20 degrees C.

Clinical evaluation of immediate loaded upper anterior single implants.

Among the guidelines to be followed in the selection of patients who are suitable for treatment with dental implants, there must be accurate assessment and evaluation of the factors that will lead to a functionally long-lasting and aesthetically pleasing result. The latter, which includes the maintenance and development of hard and soft tissues, undoubtedly presents a significant challenge in clinical implantology. The purpose of this study was the clinical evaluation of the methods currently available for the aesthetic restoration of the anterior maxilla using single implants that were loaded immediately. Forty-three patients were treated over 2 years using single implants with immediate nonfunctional loading. The patients were divided into two groups, groups A and B (i.e., immediate implant installation and late implant installation, respectively). Guided bone regeneration techniques were performed in 10 patients in group A and three patients in group B and involved buccal fenestrations orbuccal dehiscence around the implants. The parameters studied were: 1) the anatomical requirements necessary in selecting such patients and the limitations that might affect (to a lesser or greater degree) the desired results; 2) the planning and application of surgical techniques, both with immediate and short-term delay postextraction implantation, as well as the placing of implants in areas with long-term dental loss; and c) the results, after radiologic and clinical follow-up visits every 6 months, for an overall period of 2 years. No implant failure was recorded, and the therapeutic procedures were considered completely successful in all cases, without significant radiographic peri-implant marginal bone loss (i.e., average bone loss in mm +/- SD, 0.75 +/- 1.05 in group A and 0.875 +/- 0.625 in group B) or significant clinical differences in peri-implant sulcus depth (average difference in mm +/- SD, 0.3 +/- 0.2 in group A and 0.4 +/- 0.375 in group B). In cases where guided bone regeneration techniques were applied, the results were considered successful and final, and the aesthetic results were deemed more satisfactory than was expected. The procedure was successful in all cases in terms of both osseointegration and aesthetics. The use of dental implants with nonfunctional loading in particularly sensitive aesthetic areas is recommended unreservedly, given the existence of the anatomical requirements, good initial stability, and the absence of extensive bone loss in the area receiving the implant. In addition, application of this treatment method leads, within a very short time, to a particularly successful aesthetic result, reducing the number of surgeries and the duration of treatment.

Effect of autogenous harvest site location on the outcome of ridge augmentation for implant dehiscences.

Treatment planning for the placement of an implant in a site with a thin crestal ridge should address the probability that a buccal dehiscence will result. The aim of the present investigation was to perform guided bone regeneration (GBR) around implants with buccal dehiscences and evaluate the outcomes of using autogenous bone grafts harvested from three different intraoral sites. Forty-six Osseotite implants, 4 mm in diameter, were placed in thin crestal ridges, resulting in an uncovered implant surface from the buccal aspect. The lengths of the buccal dehiscences ranged from 3 to 7 mm as measured from the implant cervix to the most apical extent of the uncovered threads. A standard GBR technique was carried out to augment the bone defect around the buccal implant surface immediately after implant placement. The cases were divided into three groups according to receipt of an autogenous bone graft from the ramus, tuberosity, or mandibular symphysis. In all cases, e-PTFE membranes were used to cover the grafted areas. Grafted sites were exposed after 6 months, membranes were removed, and residual distance between the implant cervix and most uncovered thread was recorded. All grafting materials were able to produce a certain degree of bone regeneration. In terms of bone change level, the three groups were not equal. The mandibular symphysis group exhibited the highest mean bone growth level, followed by the ramus group. The tuberosity produced the poorest result. Mandibular and ramus autogenous bone grafts represent the best choice in materials for GBR procedures around implants, while tuberosity bone grafts can be used as an alternative.

Osseointegration of Osseotite and machined titanium implants in autogenous bone graft. A histologic and histomorphometric study in dogs.

It has been shown that a roughened implant surface results in a higher percentage of bone to implant contact (%BIC) than a machined one. A modified implant surface using a dual thermo-acid etching process (Osseotite) has been introduced and evaluated clinically, mechanically and histologically. The aim of the present study was the histological evaluation of the %BIC between the Osseotite or machined surfaces and the autogenous bone graft. Twenty-two custom-made split-type 10-mm-long implants having two opposing surfaces (Osseotite and machined) were placed between the cranial and caudal dorsal iliac spine at the iliac wing of two adult mongrel dogs. An artificial bone defect was created leaving a 2 mm empty space around the coronal 5 mm of the implants, while the apical 5 mm was stabilized in the existing basal bone. The defects around the implants were filled with particulate autogenous bone graft, covered by an Osseoquest membrane, and left to heal for 5 months. All inserted implants showed a complete integration in the bone tissue. It was found that the resulting %BIC at the Osseotite surface was significantly higher than at the machined one in both regenerated (46.44+/-15.81% vs. 28.59+/-12.04%) and basal bone areas (32.32+/-15.09% vs. 17.25+/-7.40%). The findings of this study imply that the use of autogenous bone graft resulted in significantly higher %BIC values in the regenerated area than in the basal bone area itself, for both implant surfaces.