Round Burr Research Articles

Pectoralis Major Tendon Repair: Transosseous Suture Technique

Background: Pectoralis major ruptures are rare injuries that occur in young men between 20 and 40 years of age, typically during resistance training in the eccentric phase of muscle contraction. As the incidence of these ruptures increases with increasing activity levels and use of anabolic steroids, it is important to understand effective repair techniques. Indications: Repair of the ruptured pectoralis major tendon is indicated for young, active patients seeking to regain full functionality of the affected upper extremity. Technique Description: In short, after the pectoralis major is identified, the insertion site is revealed just lateral to the biceps tendon. The site for the bone trough is then exposed through cauterization of superficial tissue, and a cortical bone trough is drilled vertically using a small round burr. The location of 3 pilot holes is identified just lateral to the cortical bone trough, and then the holes are drilled to allow for placement of the anchors later in the procedure. The tendon itself is then identified, and sutures are placed in the bulk of the muscle tendon in a Krackow fashion. After the tendon is properly sutured, it is placed under tension to test the structural integrity of the suture pattern and ensure proper load capacity. The sutures are then passed through the pilot holes, the tendon is pulled down into the trough, and the sutures are tied down to the bone. Results: After an appropriate rehabilitation protocol is followed for up to 6 months postoperatively, the transosseous suture technique in the context of pectoralis major tendon repairs allows for adequate tissue to bone healing and near-complete restoration of patient functionality and strength. Conclusion: Acute repair of pectoralis major tendon tears using a transosseous suture technique is effective in restoring upper extremity strength and functionality and is associated with high patient satisfaction. The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Paper 07: Biomechanical Evaluation of Posterior Shoulder Instability with a Clinically Relevant Posterior Bone Loss Model

Objectives: Though recognized as a risk factor, posterior glenoid bone loss has only recently been characterized and is distinctly different than anterior glenoid bone loss patterns. Existing biomechanical studies are limited by employment of anterior glenoid bone loss models which are different in both orientation and morphology than posterior glenoid bone loss, and testing in a single neutral arm position thus not fully accounting for the contribution of capsuloligamentous structures in various at-risk arm positions. The purpose of this study was to evaluate the biomechanical effectiveness of a posterior labral repair in the setting of a clinically relevant bone loss model using 3-dimensional computed tomography modeling of patients with recurrent posterior shoulder instability in various at-risk arm positions. Methods: Ten fresh-frozen cadaveric shoulders (mean age: 55.4 years, range: 39-65) were prepared by removing all tissue except the capsule and distal rotator cuff insertions. A joint coordinate frame was established, the specimens were potted, then mounted to a customized fixture on 6-degrees-of-freedom robotic arm. A posterior labral tear was created, then repaired with 3 horizontal mattress sutures and secured by drilling 6 transosseous holes along the peripheral glenoid face exiting the anterior glenoid neck. The sutures were secured for the labral repair states to the mounted fixture under maximal tension and released for the labral tear states and for creating the sequential bone loss models. Bone loss models were created based off a cohort of CT data on patients undergoing revision posterior labral repair surgery to develop 2 clinically relevant 3D models of glenoid bone loss: the first simulating the mean bone loss in this cohort and represented 7% or small bone loss; the second was the mean + 2SD representing 28% or large bone loss. The bone loss was created on each specimen with a 3mm round burr to match each respective 3D printed template (Figure 1). Each specimen was tested in 7 consecutive states: (1) native anatomy, (2) posterior labral tear (6-9 o’clock), (3) posterior labral repair, (4) mean posterior glenoid bone loss with labral tear, (5) mean posterior glenoid bone loss with labral repair, (6) large posterior glenoid bone loss with labral tear, and (7) large posterior glenoid bone loss with labral repair. Each state underwent 75N of posterior-inferior force and 75N of compression during the four tests at 60 and 90 degrees of flexion and 60 and 90 degrees of scaption. Posterior-inferior translation, lateral translation, and dislocation force were measured for each condition. Statistical analysis was performed using two-factor random-intercepts linear mixed-effects models. Results: Compared to the labral tear state, significant increases in dislocation forces occurred with labral repair independent of bone loss state or arm position with values as follows: 14.8N (60° scaption), 12.2N (90° scaption), 11.1N (60° flexion), and 10.1N (90° flexion) with mean 12.1 ± 2.0N across all arm positions (Figure 2). Dislocation force significantly decreased between no bone loss and small bone loss (mean 12.4 ± 0.7N) and between small bone loss and large bone loss (mean 11.8 ± 2.1N) regardless of labral state in all arm positions (table 1). Posterior-inferior translation significantly decreased with labral repair compared to labral tear states independent of bone loss state in all arm positions (Table 1). Lateral translation of the humeral head significant increased when the labrum was repaired independent of bone loss state in all arm positions except 90° scaption and decreased progressively in all bone loss states in all arm positions (table 1). In the native state, the shoulder significantly translated posterior-inferior in scaption at 60° and 90° elevation compared to flexion (p<0.017) and was most unstable in 60° scaption with 29.9 ± 6.1mm posterior-inferior translation (Figure 3). Conclusions: This is the first study to biomechanically evaluate posterior glenoid bone loss using a clinical model in various at-risk arm positions on a 6 degree-of-freedom robot and through a precise linear effects model has established values for the increase in dislocation force posterior labral repair provides regardless of bone loss. The most significant finding of the study is that independent of bone loss, labral repair reduced posterior dislocation forces by 12.1 ± 2.0N and significantly decreased posterior-inferior translation. With a mean decrease in dislocation force of 12.4 ± 0.7N with small (7%) bone loss, labral repair alone may be enough to restore shoulder stability in most individuals. However, significant increases in posterior bone loss may require bony augmentation for adequate stability based on individual factors such as age and activity level. [Table: see text][Figure: see text][Figure: see text]

Ex vivo Evaluation of a New Drill System for Placement of Percutaneous Bone Conduction Devices.

The procedure for installation of a percutaneous bone-conducting device has undergone significant improvements since its introduction 40 years ago. Today, the linear incision technique with tissue preservation (LITT-P) and the minimally invasive procedure (MIPS) are the most commonly used approaches. In both these techniques, a gradual increase of the osteotomy using a three-step drilling sequence is utilized, as this approach can allow a stepwise deepening and widening of the osteotomy in the mastoid and can prevent bone overheating. A new minimally invasive procedure (MONO) has been developed that allows an osteotomy to be performed and enables complete removal of the bone volume in one single drill step for a 4 mm implant using a novel parabolic twist drill. Here, the feasibility of the MONO procedure was qualitatively and quantitatively evaluated in terms of the dura response to drill trauma in comparison with the outcomes achieved with guide drills used for the LITT-P and MIPS techniques. Fresh frozen temporal bone from a human cadaver was subjected to penetration by three drills beyond the base of the mastoid bone to different depths. The sites were evaluated, and the damage to and possible penetration of the dura were determined. The results showed that for a drill depth exceeding mastoid bone thickness by not more than 1 mm, damage to the dura was limited or nonexistent, whereas for a drill depth exceeding bone thickness by 2 mm, damage increased, or the dura was penetrated. There was a trend toward more damage and penetration for both the round burr and MIPS guide drill compared with the MONO drill bit. From this experimental ex vivo study, it can be concluded that if the dura is encountered, the MONO system is not more inclined to penetrate the dura than the conventional LITT-P and MIPS systems.

Influence of different separating mediums applied on the immediate dentin sealing in the tensile strength of temporary restorations

Objective: To evaluate the ability of different separating mediums to prevent adhesion between provisionalrestorations and hybridized dentin surfaces when used with the Immediate Dentin Sealing technique (IDS).Material and Methods: 120 extracted human teeth — 40 premolars and 80 molars — were selected to integrateacrylics samples separated into 4 different groups (n=10) according to the separating medium used for IDSprotection. Forty samples were made of three teeth mounted in a self-cure acrylic resin block (Jet, Classic, SãoPaulo, Brazil) arranged side by side, simulating the positioning and proximal contacts present in the dental archbetween the second premolar, first molar and second molar. A standard dental preparation for ultra-thin occlusalveneer was performed and complete occlusal dentin exposure was achieved by selective removal of the occlusalenamel with a high-speed conical round burr (Code: 1801.4138 FG, KG Sorensen, Medical Burs Ind. e Com. dePontas e Brocas Cirúrgicas Ltda, São Paulo, Brazil). Dentin hybridization were performed on the control groupand 3 different groups of separating mediums (n=10): PC—commercial provisional separating agent (Pro-VCoat, Bisco, Schaumburg, USA); GG—glycerin gel (K-Y Gel; Johnson & Johnson Industry and Commerce LTDA,São Paulo, Brazil); PJ—petroleum jelly (Rioquímica, São Paulo, Brazil). Provisionalization were manufacturedon the prepared teeth. After 2 weeks, the tensile test was performed, and the analysis of the failure pattern wasperformed by 3D laser confocal microscopy and Scanning Electron Microscopy (SEM). The data were analyzedwith the 1-way ANOVA and the Tukey test (a = 0.05). Results: Significantly lower tensile strength values werefound for the commercial provisional separating agent (30.39 ± 10.01 N) compared to others (p < 0.05).Conclusion: The commercial provisional separating agent showed greater effectiveness on protecting hybridizeddentin against the provisional restorations. KEYWORDSDental bonding agent; Dental restoration temporary; Immediate dentin sealing.

Minimally Invasive Interphalangeal Arthrodesis.

Distal interphalangeal joint fusion is usually the surgical treatment for primary or posttraumatic osteoarthrosis when conservative measures fail. All fusion techniques aim for solid fusion with joint chondral resection, bone to bone contact and stable fixation in an adequate position. This is performed with an open dorsal approach considering the risks of soft tissue complications. We describe a technique of resecting bone cartilage and getting stable fixation with 2 mini incisions, 1 lateral and 1 in the digital pulp. Using a digital block anesthesia and under fluoroscopy, a small round burr is introduced into the joint by a lateral joint line stab incision. The joint space is enlarged by manual traction on the finger. After adequate cartilage resection, good bone to bone contact in an adequate position is fixed with a cannulated Herbert screw inserted percutaneously by the finger pulp. We describe 4 cases operated with this technique, 3 for pain and 1 for esthetics. All 4 demonstrated good results and were satisfied. X-rays showed solid fusion in 8 to 12 weeks. There was one complication with skin burning because of the burr heating and the authors describe how to avoid it. Minimally invasive distal interphalangeal joint fusion is a simple, reproducible technique that maintains the important steps for a solid arthrodesis with the advantage of preserving the soft tissue envelope.

Surgical Burr-Assisted Lateral Osteotomy Technique in Septorhinoplasty.

Achieving aesthetic and functional results in rhinoplasty requires meticulous techniques, and postoperative edema, ecchymosis, and pain can deteriorate the desired outcomes. Different osteotomy techniques are defined to have optimal outcomes while reducing edema, ecchymosis, and pain. In this study, the authors compared conventional and power-assisted surgical burr osteotomy techniques in terms of early postoperative complications. Patients who underwent primary open septorhinoplasty were included in the study and were divided into 2 groups. The first group had lateral endonasal osteotomy with conventional guided osteotomes, and the second group had lateral osteotomy with surgical round burr. Edema and ecchymosis scoring systems were used on the postoperative first, third, and seventh day to evaluate postoperative edema and ecchymosis, and the visual analog scale was used to evaluate pain severity on the postoperative period. Out of 70 patients who had undergone septorhinoplasty, 36 received conventional osteotomy and 34 received surgical round burr osteotomy. Periorbital ecchymosis scores were significantly lower in the second group on the postoperative first, third, and seventh days. The periorbital edema scores were significantly lower in the second group on the first postoperative day but no difference was found between postoperative days 3 and 7. Also, the pain scores were significantly lower in the second group. Osteotomy with surgical round burr yields less ecchymosis, edema, and pain in the early postoperative period than conventional osteotomy in primary septorhinoplasty patients.

Sealing Ability of Calcium Silicate-based Materials in the Repair of Furcal Perforations: A Laboratory Comparative Study

To assess the sealing ability of two calcium silicate-based materials in the treatment of iatrogenic furcal perforations using a dye-penetration leakage model. Furcation perforations were performed using a size 12 round burr on the pulp chamber floor of 20 first mandibular molars. The teeth were then randomly divided into two groups, two additional molars served as negative controls. The defects were then filled with mineral trioxide aggregate (MTA) Angelus in the first group and Biodentine in the second group. Leakage at the repaired sites was then evaluated using the methylene blue dye penetration technique. Significant differences in microleakage were found between the two groups at 72 hours (p < 0.001). MTA Angelus had greater dye penetration than Biodentine with a statistically significant difference. Subsequently, the sealing ability of Biodentine was significantly better than MTA Angelus (p < 0.001). However, the mean values of leakage and inadequate adhesion were significantly different from the theoretical value for both the MTA Angelus (p < 0.001) and Biodentine (p < 0.001). The current results suggested that Biodentine possesses higher sealing quality than MTA Angelus. Yet, both materials are not ideal and still need improvement to ensure perfect adhesion in case of furcal perforation. This article aims to compare the sealing ability of one dental repair material over another, after iatrogenically producing a furcal perforation. Leakage resistance and sealing ability are important factors in favoring the outcome of an endodontic treatment of a tooth that could otherwise be condemned for extraction.

Simple New Screw Insertion Technique without Extraction for Broken Pedicle Screws.

Spinal transpedicular screw fixation is widely performed. Broken pedicle screw rates range from 3%-7.1%. Several techniques have been described for extraction of broken pedicle screws. However, most of these techniques require special instruments. We describe a simple, modified technique for management of broken pedicle screws without extraction. No special instruments or drilling in an adjacent pedicle are required. We used a high-speed air drill with a round burr. With C-arm fluoroscopy guidance, the distal fragment of a broken pedicle screw was palpated using free-hand technique through the screw entry hole. A high-speed air drill with a round burr (not a diamond burr) was inserted through the hole. Drilling began slowly and continued until enough space was obtained for new screw insertion. Using this space, we performed new pedicle screw fixation medially alongside the distal fragment of the broken pedicle screw. We performed the insertion with a previously used entry hole and pathway in the pedicle. The same size pedicle screw was used. Three patients were treated with this modified technique. New screw insertion was successful in all cases after partial drilling of the distal broken pedicle screw fragment. There were no complications, such as screw loosening, dural tears, or root injury. We describe a simple, modified technique for management of broken pedicle screws without extraction. This technique is recommended in patients who require insertion of a new screw.

Is More Cortical Bone Decortication Effective on Guided Bone Augmentation?

This study aims to evaluate the possible effect of more cortical bone decortication (CBD) on guided bone augmentation. A total of 16 New Zealand rabbits and 32 titanium domes were used. No cortical bone decortication was applied to the control group and in the study groups, the cortical bones were decorticated with a round burr (Group A: 1 hole with bleeding, Group B: 5 holes with bleeding, Group C: a thin layer of compact bone was completely removed with no bleeding). Then 2 titanium domes were placed on the calvarium of each rabbit with hydroxyapatite/beta-tricalcium phosphate. After 3 months, the animals were sacrificed and specimens were sent for histological and histomorphometric analysis. Histological and histomorphometric analysis showed that bone decortication with burr significantly increased new bone regeneration in all the experimental groups compared with the control group (P <0.05). No statistically significant difference was determined between the study groups. In conclusion, CBD, which has no negative impact on surgery, has a positive effect on guided bone augmentation. However, a greater amount of CBD does not have a greater effect.

Endoscopic Surgical Removal of Calcific Tendinitis of the Rectus Femoris: Surgical Technique

Calcific tendinitis of the rectus femoris (CTRF) is an under-recognized condition and, because of its self-limiting nature, is usually managed conservatively. Nevertheless, when nonsurgical therapy fails, further invasive alternatives are required. At this point, arthroscopic resection provides a minimally invasive and interesting alternative to open surgery. The aim of this work is to report the surgical technique of endoscopic surgical removal in patients with CTRF at the periarticular region of the hip joint. Endoscopic surgical removal of CTRF was performed without traction following anatomic landmarks for hip arthroscopy portal placement. We used the anterolateral portal and the proximal accessory portal to obtain access to the lesion. A shaver and radiofrequency device are useful tools to depict the calcific lesion while the whole resection is performed with a 5-mm round burr. Intraoperative fluoroscopy control during the entire procedure is essential. Endoscopic treatment of calcific tendinitis of the hip is a valuable technique in the treatment of patients who do not respond to conservative treatment.

How Safe Is High-Speed Burring in Spine Surgery? An In Vitro Study on the Effect of Rotational Speed and Heat Generation in the Bovine Spine.

In vitro animal cadaveric study. To identify the appropriate rotational speed and safe bone distance from neural tissue during bone burring in spinal surgery. Bone burring is a common step in spinal surgery. Unwanted frictional heat produced during bone burring may result in thermal injury to the bone and adjacent neural structure. One of the important parameters influencing the bone temperature rise during bone burring is rotational speed. This laboratory-based animal study used bovine spine bones, and the tests were conducted using a steel round burr. The bone temperature was measured simultaneously with thermocouple at the distances of 1 mm, 3 mm, and 5 mm from the burring site during the burring process. The bone burring was done with 4 different rotational speeds of 35,000 revolutions per minute (rpm), 45,000 rpm, 65,000 rpm, and 75,000 rpm. This study showed that increasing the rotational speed significantly elevated bone temperature. The threshold temperature of 47°C was reached when bone was burred for 10 seconds, with a rotational speed of 45,000 rpm. The mean bone temperature measured at a distance 1 mm from the burring site for all 4 rotational speeds was always higher than that measured at a distance of 3 mm and 5 mm and this difference was statistically significant (P < 0.001). There was no significant difference between the mean bone temperature measured at a distance of 3 mm and 5 mm (P > 0.05). Taking 47°C as the threshold temperature for causing significant impairment to the regenerative capacity of bone, a rotational speed of lower than 45,000 rpm is preferable so as to minimize thermal injury to bone tissue. We also concluded that a 3-mm distance between the site of burring and the neural tissue is a safe distance. N/A.

The effect of an Er,Cr:YSGG laser on external adaptation of healthy and decayed cavities

The aim of this study was to evaluate the influence of chlorhexidine and Er,Cr:YSGG laser irradiation on the bond strength and external adaptation in mixed healthy and caries-affected class V cavities before and after thermal cycling. Thirty-six cavity preparations were made in mixed class V buccal human molars, half of them being artificially caries-induced. Any remaining affected dentin was removed from the cavity with a round burr at low speed. The teeth were divided into six groups, according to cleaning agent for both healthy and caries-induced dentin: no treatment, chlorhexidine and erbium, chromium-doped: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser irradiation. A Filtek P90 (3M ESPE, St Paul, MN, USA) silorane adhesive restorative system was used. The specimens were subjected to 5000 thermal cycles (5–55 °C 60 min). Epoxy replicas were obtained to characterize the external adaptation under scanning electron microscopy. The average percentages of non-continuous margins were 5.41% and 6.49% in enamel dentin before thermal cycling and 25% and 33.7% after thermal cycling, respectively. The caries-affected and laser irradiated cavities showed higher non-continuous margins. Thermal cycling was able to raise the percentage of non-continuous margin for all groups. Chlorhexidine did not affect the marginal adaptation results, and the Er,Cr: YSGG laser irradiation showed significantly worse results compared with the control group.

Real-Time Mandibular Angle Reduction Surgical Simulation With Haptic Rendering

Mandibular angle reduction is a popular and efficient procedure widely used to alter the facial contour. The primary surgical instruments, the reciprocating saw and the round burr, employed in the surgery have a common feature: operating at a high-speed. Generally, inexperienced surgeons need a long-time practice to learn how to minimize the risks caused by the uncontrolled contacts and cutting motions in manipulation of instruments with high-speed reciprocation or rotation. A virtual reality-based surgical simulator for the mandibular angle reduction was designed and implemented on a CUDA-based platform in this paper. High-fidelity visual and haptic feedbacks are provided to enhance the perception in a realistic virtual surgical environment. The impulse-based haptic models were employed to simulate the contact forces and torques on the instruments. It provides convincing haptic sensation for surgeons to control the instruments under different reciprocation or rotation velocities. The real-time methods for bone removal and reconstruction during surgical procedures have been proposed to support realistic visual feedbacks. The simulated contact forces were verified by comparing against the actual force data measured through the constructed mechanical platform. An empirical study based on the patient-specific data was conducted to evaluate the ability of the proposed system in training surgeons with various experiences. The results confirm the validity of our simulator.

Evaluation of flexural strength and shear bond strength of repaired microhybrid composite with varied surface treatments

The aim of this study was to evaluate the effect of three different surface treatments on the flexural strength (FS) and shear bond strength (SBS) of repaired microhybrid composite. For the FS test composite specimens (n = 36: 2 mm ´ 2 mm ´ 12.5 mm) used for repair were shaped in a silicone mould. For the SBS test composite specimens (n = 36: diameter = 8 mm, thickness = 3 mm) used for repair were shaped in a metal mould, cured in visible light, and embedded in dental stone. Three different methods of surface preparation were evaluated: group A (control) specimens were treated by etching with 35 % phosphoric acid, group B specimens were air abraded with 50 μm aluminium oxide at 100 psi and group C specimens received two parallel 1 mm deep grooves using a 1/4 round burr before being treated by etching with 35 % phosphoric acid. After surface treatment a bonding agent was placed on each specimen and light-cured. Repairs were accomplished by adding more composite to the FS or SBS specimens. Specimens were thermocycled 500 times between 5 °C and 55 °C with 30 s dwell times. All specimens were tested by loading to failure at a rate of 0.5 mm/min using an Instron universal testing machine. Statistical analysis was done using ANOVA test to compare the means of each group within the SBS or FS tests and Tukey post hoc tests (p < 0.05) were used to detect any differences. Mean FS values (MPa) were: group A = 60.5 ± 9.9, group B = 73.9 ± 13.2 and group C = 81.3± 14.3. Mean SBS values (MPa) were: group A = 24.5 ± 4.4, group B = 28.5 ± 4.3 and group C = 27.0 ± 2.8. The FSs of groups B and C were significantly greater than in group A but there was no significant difference between group C and group B. For the SBS test group B was significantly greater than in group A but with no significant differences between groups C and B. Acid etching alone was not very effective in producing well-bonded composite repairs. Mechanical retention was more effective than acid etching and as effective as or more effective than air-abrasion (p < 0.05) for repaired composite specimens. Either mechanical retention or air abrasion is recommended prior to repairing an existing composite restoration to achieve the highest bond strength.

Plate-Only Open Door Laminoplasty Maintains Stable Spinal Canal Expansion with High Rates of Hinge Union and No Plate Failures

Prospective clinical series. To evaluate the ability of plate-only laminoplasty to achieve stable laminar arch reconstruction and to determine the rate and time course with which bony healing occurs in such constructs. Reconstruction of a stable laminar arch with sufficient room for the decompressed spinal cord is a desired goal when performing cervical laminoplasty for myelopathy. Traditional forms of laminoplasty fixation, such as sutures, bone struts, and ceramic spacers, may be associated with complications including loss of fixation, dislodgement with neurologic compromise, and premature laminoplasty closure. Plates, in contrast, provide more rigid fixation. Plate-only laminoplasty is gaining popularity as a method of laminoplasty fixation, but there is little data on its effectiveness. Fifty-four patients who underwent open door laminoplasty for cervical myelopathy and had available postoperative computed tomography (CT) scans formed the basis of this study. In all cases, a 4-mm round burr was used to create the hinge at the junction of the lateral mass and lamina by completely removing the dorsal cortex and thinning the ventral cortex until a greenstick deformation of the hinge could be produced. Laminoplasty plates were used as the sole method of fixation. No supplemental bone graft struts were used on the plated side, and the hinge side was not bone grafted. Axial CT scans obtained at 3, 6, and 12 months postoperatively were assessed for plate complications and bony healing of the hinge. No plate failures, dislodgements, or premature closures occurred in any of the levels at any time postoperatively. Computed tomography scan review demonstrated that 55% of levels were healed at 3 months, 77% at 6 months, and 93% at 12 months. At each timepoint, C6 and C7 had the highest hinge healing rates. Laminar screw backout was seen in 5/217 (2.3%) of levels, but was not associated with plate dislodgement, laminoplasty closure, or neurologic consequences, and did not occur in any case in which 2 laminar screws had been placed. Plate-only laminoplasty provided stable reconstruction of an expanded laminar arch with no failures, dislodgements, adverse neurologic consequences, or premature closures in 217 levels. Ninety-three percent of hinges demonstrated radiographic union at 12 months, and even those that did not heal by CT scan criteria maintained patent expansion of the spinal canal without adverse neurologic consequences. Supplemental bone graft does not appear necessary when plated laminoplasty is performed.

Matrix Metalloproteinase-3 Accelerates Wound Healing following Dental Pulp Injury

Matrix metalloproteinases (MMPs) are implicated in a wide range of physiological and pathological processes, including morphogenesis, wound healing, angiogenesis, inflammation, and cancer. Angiogenesis is essential for reparative dentin formation during pulp wound healing. The mechanism of angiogenesis, however, still remains unclear. We hypothesized that certain MMPs expressed during pulp wound healing may support recovery processes. To address this issue, a rat pulp injury model was established to investigate expression of MMPs during wound healing. Real-time RT-PCR analysis showed that expression MMP-3 and MMP-9 (albeit lower extent) was up-regulated at 24 and 12 hours after pulp injury, respectively, whereas expression of MMP-2 and MMP-14 was not changed. MMP-3 mRNA and protein were localized in endothelial cells and/or endothelial progenitor cells in injured pulp in vivo. In addition, MMP-3 enhanced proliferation, migration, and survival of human umbilical vein endothelial cells in vitro. Furthermore, the topical application of MMP-3 protein on the rat-injured pulp tissue in vivo induced angiogenesis and reparative dentin formation at significantly higher levels compared with controls at 24 and 72 hours after treatment, respectively. Inhibition of endogenous MMP-3 by N-Isobutyl-N-(4-methoxyphenylsulfonyl)-glycylhydroxamic acid resulted in untoward wound healing. These results provide suggestive evidence that MMP-3 released from endothelial cells and/or endothelial progenitor cells in injured pulp plays critical roles in angiogenesis and pulp wound healing.

Validity of single- and multislice CT for assessment of mandibular condyle lesions

The purpose of this study was to evaluate and to compare the validity of the different CT image protocols (single- and multislice CT) in the analysis of simulated mandibular condyle lesions. Simulated lesions were created in 15 dry mandibles using a dental round burr. The mandibles were then submitted to a single slice CT, and the same specimens were subsequently submitted to a multislice CT. The analysis was performed by two previously calibrated examiners in four protocols: (1) single slice-axial, (2) multislice-axial, (3) single slice-axial/multiplanar reconstructed (MPR) and (4) multislice-axial/MPR. The examiners evaluated the absence or presence of bony destruction and their localization in each protocol, considering also some bony erosion caused by its reabsorption. Statistical analysis was carried out using validity and chi(2) tests to compare the protocols. Protocol 1 presented the lowest validity values (62.7%). The validity of Protocols 2 and 3 was 66.2% and 72.7%, respectively. The highest value of validity was 93.1% and corresponded to Protocol 4. All CT-imaging protocols were considered accurate for mandibular condyle lesions assessment. The association of axial with MPR images using multislice CT demonstrated highest accuracy. A new imaging protocol was established for diagnosis of these lesions.

Canal configuration of the mesiobuccal root of the maxillary first molar of a Japanese sub-population.

The aim of this study was to determine the percentage of anatomical canal configurations of the mesiobuccal root of the maxillary first molar in Japanese patients. Three hundred teeth were obtained from general dentists who knew absolutely that they were extracted from Japanese patients. The distobuccal and palatal roots were amputated for radiographic convenience. Preoperative radiographs were taken of the remaining crown and mesiobuccal root (MBR) from mesiodistal and buccopalatal directions for each tooth. Routine endodontic access cavities were prepared and size 08 files were placed through the orifice into the MBR until they were seen at the apex. In some cases preparation of the canal orifice with a long shank round burr was necessary to gain access. In seven teeth, no access to the apex was possible and these teeth were eliminated. In the other 293 teeth, the MBR canal(s) was (were) enlarged up to size 15 file. If another canal opening was found at the apex a 08 file was inserted into the second opening and passed coronally. Postoperative radiographs with file(s) in place were taken from the two directions, as before. Of the 293 teeth, 123 (42.0%) were Type II, 89 (30.4%) showed Type III systems and 10 (3.4%) were Type IV. Suggestions for identification and treatment of the second canal in the MBR are presented. The proportion of cases with two canals in the mesiobuccal root of maxillary first molars from Japanese patients was high and similar to that described from studies of other ethnic populations.

Microbiological validation of assessments of caries activity during cavity preparation.

The operative management of primary and secondary caries assumes that all discoloured tissue at the enamel-dentine junction (EDJ) represents active disease and this is removed to arrest the carious process. This study aims to establish clinical criteria to differentiate between active and arrested caries at the EDJ using microbiological assessment of dentine samples to verify its clinical status. Radiographs were available for posterior teeth. Cavities (n = 205) were prepared under rubber dam. After gaining access, areas of the EDJ were chosen and assessments made of consistency (soft, medium, hard), colour (dark brown, mid-brown, pale) and moisture content (wet, dry). Dentine was removed by using a No. 3 round burr and placed in 1 ml of bacteriological culture broth. This sampling procedure was repeated at the same site once during cavity preparation and again when the cavity was judged as fully prepared. Samples were vortexed, diluted and cultured to give viable counts of the total anaerobic microflora, mutans streptococci and lactobacilli; viable counts were expressed as log10 (CFU per sample +1). Results showed no significant differences between the microflora of primary and secondary caries. The number of bacteria recovered diminished significantly as cavities were completed. Initial samples from soft and wet lesions harboured significantly more bacteria, lactobacilli and mutans streptococci than samples from medium, hard or dry lesions. Lesions visible on radiographs harboured more bacteria, including lactobacilli and mutans streptococci, while dentine colour was not discriminatory.(ABSTRACT TRUNCATED AT 250 WORDS)

A Numbered, Metal Color-Band for Game Birds

A color-band has been used with success on prairie chickens (Tympanuchus cupido) in Wisconsin since the winter of 1955-56. On a colored-aluminum blank band, size 7A, a number is stamped with a /4-inch die. The color is then routed out with a dentist's No. 3 round burr, resulting in a silvery number on a colored background. The band is used as part of a color combination, the rest of which (on the other leg) consists of a numbered, colored plastic band above an aluminum stateissued band the color of which is changed annually on a 5-year rotation. Sight recognition of the color combination alone tells the year and place of banding; the additional recognition of either number identifies the individual bird. Color-banding has long been an important part of prairie chicken studies in Wisconsin (Hamerstrom, F. N., Jr., and Frances Hamerstrom 1949. Auk 66(4):313-337). The scheme which has been used for the last 8 years is as follows: On the right leg the bird carries the usual serially numbered aluminum band issued by the State of Wisconsin. Above this is a colored plastic band bearing a large number, which we call the reader band. On the left leg, there is a single colored-aluminum band, also with a number; this is the left-leg band and the main subject of this report. The color of the state band is changed each year in a 5-year rotation in which it is plain aluminum the first year and then successively red, green, black, and yellow. Reader bands are white, yellow, green, and light red (or cerise pink of the National Band and Tag Co., Newport, Kentucky, whose Bandette style 4-907, size 7, we use). The left-leg bands have the same colors as the state bands, except that we have not used plain aluminum. All three bands are approximately the same size as the state band, which corresponds closely to size 7A among bands issued by the U. S. Fish and Wildlife Service; measurements are % inch wide, 1%2 inch outside diameter, and %74 inch inside diameter. The numbers on both the reader and left-leg bands are about 5%6 inch high. Numbers are black on the reader bands and silver (actually, aluminum as described below) on the left-leg bands. With good light and a 20-power spotting scope the numbers on the reader bands can b read at distances up to 90 yards; white and yellow bands can be read somewhat f rther than green and red. The best leftleg bands can be read almost as far as reader bands: black bands can be read at greater distances than the others, with red a close second, then green, and yellow a poor fourth. The difficulty with the yellow and green bands is that there is little contrast between the silver numbers and the background colors. Contrast can be heightened by intensifying the background colors, especially in the case of green, but this leads to other problems; in poor light, dark green is easily confused with black, while intensification of the yellow color produces a band which is more orange than yellow, and this can be confused with faded red. Using this marking system, birds can be recognized by sight as individuals or, failing that, even partial identification can give valuable information. For example, there is 1 A contribution from Wisconsin PittmanRobertson Projects W-13-R and W-79-R.