Prevention of third molar development in dog with long pulse diode laser: a preliminary report.

INTRODUCTION: Wisdom teeth continue to plague man with a high rate of frequency. It may be possible to prevent their development in children at an early age with a non- or minimally invasive technique, even before the tooth begins to form, by treating the soft tissue overlying the site of their development. A previous study that treated the intra-oral soft tissues of newborn rats with a 20 watt diode laser stopped third molar development up to 80% of the time with minimum observable side effects. This brief report describes a similar use of the diode laser in a limited number of young beagle pups. It is the first reported attempt at preventing third molar development in an animal model close in size to man. MATERIALS AND METHODS: Four 6-7 week old beagle pups were treated on one side of their mandibles with either a 20 or a 100 watt, 800 nm diode laser at a time third molar tooth buds are just beginning to form under the oral mucosa. Six months following treatment, the pups were examined intra-orally and radiographically for evidence of third molar formation. RESULTS: The two intra-oral sites that received the 20 watt diode laser treatment showed normal third molar development. The two intra-oral sites that received the 100 watt diode laser treatment did not develop third molars. CONCLUSIONS: The diode laser may be capable of selectively stopping third molar development and further studies are warranted.

Evaluation of a unique bovine collagen matrix for soft tissue repair and reinforcement.

Veritas Collagen Matrix, a product of Synovis Surgical Innovations, is derived from bovine pericardium. It can be used for a number of applications including body wall repair and replacement. In this study, we evaluated its efficacy as an adhesion barrier in a rabbit model of uterine horn surgery. When Veritas was placed on the uterine horn stump it reduced the incidence of adhesions by 50% (n.s.) compared with untreated controls. Histologic analysis of recovered material showed that the surface was covered with a monolayer of mesothelial-like cells. In addition, there was an infiltration of host cells into the matrix of the product, which suggests a replacement of the material with host tissue.

Prevention of third molar tooth development in neonate rat with a long pulse diode laser.

BACKGROUND AND OBJECTIVES: Third molars (wisdom teeth) in humans have limited functional value and cause a high frequency of morbidity. A window of opportunity exists to stop their development. The purpose of this study is to evaluate whether a long pulse diode laser can selectively prevent third molar development in a rat animal model. STUDY DESIGN/MATERIALS AND METHODS: The study calculated theoretical diode laser parameters and irradiated 2- to 4-day-old rat pups in the posterior aspects of the oral cavity near the time of tooth bud initiation. Rats were sacrificed at 35-50 days and examined intraorally and radiographically for third molar development. Control and treated sides were compared histologically. RESULTS: Nearly half of the maxillary third molars and 80% of the mandibular third molars were selectively prevented from developing using a 20 W diode laser with infrequent, minor adverse effects on maxillary jaw growth. CONCLUSIONS: This study confirms the hypothesis that controlled, non-invasive laser treatment delivered on the surface of the oral mucosa near the site of tooth bud formation can selectively achieve third molar agenesis. It also offers hope that further innovative studies may bring about a safe, non-invasive laser treatment to selectively prevent third molar development in humans.

Selectively preventing development of third molars in rats using electrosurgical energy.

BACKGROUND: Third molars are teeth with questionable value. People who never develop third molars avoid confronting the disease and pain these teeth often cause. Since third molars do not begin to develop until children are approximately five years of age, a window of opportunity exists to therapeutically prevent this tooth's development. The dentition of neonate rats possess developmental stages of molars similar to that of five-year-old children. This pilot study tests the hypothesis that third molars can be selectively prevented from developing. METHODS: Thirty-three neonate rats received a momentary pulse of electrosurgical energy to one of their maxillary tuberosities. The tuberosities on the contralateral sides received no treatment. Intraoral and radiographic examinations of sacrificed animals occurred when they were between 47 and 52 days old. Several tuberosity areas from sacrificed animals underwent histologic examination. RESULTS: Ten rats showed no intraoral or radiographic evidence of third molar development, and six developed smaller-than-normal third molars. Development of the maxilla also was affected frequently. One treated tuberosity area that was missing a third molar showed no histologic evidence of tooth-forming tissues, cyst formation or other significant abnormal tissue changes. CONCLUSIONS: Maxillary third molars can be selectively prevented from developing in rat pups at or near the time of tooth bud initiation; however, electrosurgical energy is too powerful and uncontrollable to reliably confine its damage to only the tooth-forming tissues. CLINICAL IMPLICATIONS: Third molars may be able to be selectively prevented from developing in growing children near the time of tooth bud initiation if less-differentiated precursor tooth-forming tissues can be selectively targeted.

Application of the poly-N-acetyl glucosamine-derived rapid deployment hemostat trauma dressing in severe/lethal Swine hemorrhage trauma models.

BACKGROUND: The Rapid Deployment Hemostat (RDH) Bandage was developed for the rapid control of bleeding caused by trauma. METHODS: An extremity wound involving skin, muscle, bone, and femoral arterial injury and a 1-cm vertical incision in the abdominal aorta in swine were studied to compare the RDH Bandage, a fibrin sealant dressing and gauze to restore hemostasis. The total blood loss was determined and the survival of animals was measured. RESULTS: In the extremity injury model, the RDH Bandage reduced blood loss by 63% compared with the gauze control. In the aorta arterial incision model, the RDH Bandage required a significantly lower compression time to control bleeding compared with gauze and TachoComb. The RDH Bandage was able to stop bleeding from this injury in 100% of the tests. CONCLUSION: The RDH Bandage was superior to a commercially available fibrin bandage in controlling hemorrhage, decreasing blood loss, and increasing survival.

Comparison of poly-N-acetyl glucosamine with commercially available topical hemostats for achieving hemostasis in coagulopathic models of splenic hemorrhage.

BACKGROUND: The hemostatic quality of the poly-N-acetyl glucosamine (p-GlcNAc) patch was compared with a fibrin sealant, fibrin bandage, and cellulose patch. METHODS: A 2 x 2-cm capsular strip to a depth of 3 mm of the swine spleen was used as a source of bleeding. Splenic lacerations were created in hemophilia B dogs and treated with p-GlcNAc and Surgicel. Wounds were created in rabbits and treated with p-GlcNAc at 37degreesC and after keeping body core temperature at 29degreesC. RESULTS: Poly-N-acetyl glucosamine was able to achieve hemostasis with greater efficacy than either of the fibrin-based bandages. In the hemophilia B dog study, p-GlcNAc significantly outperformed Surgicel, with p-GlcNAc achieving hemostasis in 75% of the treated wounds compared with 17% for the cellulose patch. The hypothermia study demonstrated that p-GlcNAc is equally effective at 29degreesC and at 37degreesC. CONCLUSION: Poly-N-acetyl glucosamine was effective at controlling bleeding in animals with experimentally induced or genetic coagulopathic disorders.

The RDH bandage: hemostasis and survival in a lethal aortotomy hemorrhage model.

BACKGROUND: The Rapid Deployment Hemostat (RDH) Bandage has been designed in collaboration with the Office of Naval Research for the treatment of bleeding because of extremity trauma. It is intended as both a battlefield and civilian severe trauma wound dressing. It consists of a specific formulation of Marine Polymer Technologies' proprietary hemostatic polymer poly-N-acetyl glucosamine, and has received FDA clearance. This study compares the hemostatic capabilities of the RDH Bandage with the standard U.S Army First Aid Field Bandage (AFAFB), utilizing a controlled lethal aortotomy model of hemorrhage. MATERIALS AND METHODS: Aortic punch wounds 4 mm in diameter were made in the abdominal aortas of female Yorkshire White swine, and were allowed to bleed for 5 s before application of test materials. Test hemostats were applied to the wound with manual compression for 10 min. Total loss of blood was determined in each experiment. Bandages were removed at the end of 2 h, for those animals that survived, and the onset of re-bleeding was observed. Animals were monitored for an additional 30 min to assess survival following bandage removal. Hemostatic efficacy was judged by the total loss of blood, and the survival of the animals. RESULTS: Eighty percent of the animals treated with the RDH Bandage survived the study through the entire protocol, whereas only 40% of those treated with the Army First Aid Field Bandage survived the removal of manual compression step, and none survived following the removal of bandage after the 2 h observation/monitoring period. The average blood loss for the RDH Bandage treated animals was 234 ml, and the average blood loss for the Army First Aid Field Bandage treated animals was 1071 ml, through the observation/monitoring period. CONCLUSIONS: The RDH Bandage is significantly superior to the standard issue U.S. Army First Aid Field Bandage in the control of hemorrhage in a lethal swine abdominal aortotomy hemorrhage model, resulting in decreased blood loss and increased survival.

The effect of osteogenic protein-1 in instrumented and noninstrumented posterolateral fusion in rabbits.

BACKGROUND CONTEXT: The use of rigid instrumentation combined with bone graft makes intuitive sense given the requirements for vascular ingrowth, bone formation and a stable environment for the cellular events of healing to develop. However, with the advances of potent osteoinductive growth factors, the role of internal fixation may come into question. Whether bone morphogenic proteins (BMPs) would benefit from a more "stable" spinal segment for bone production and modeling remains unknown. In addition, it is unknown whether BMP and rigid fixation may have an additive effect on fusion healing. PURPOSE: This study is proposed to test the hypothesis that rigid fixation in the lumbar spine would be advantageous to achieve fusion for autogenous bone grafting, but fusion would occur regardless of fixation with the use of osteogenic protein (OP)-1. STUDY DESIGN/SETTING: A histologic and radiographic analysis of BMP in a rabbit lumbar fusion model. METHODS: Thirty-two rabbits were randomized into four groups: 1) control animals: in situ posterolateral L5-L6 arthrodesis using autogenous iliac crest bone graft; 2) fixation group: posterolateral arthrodesis L5-L6 with autogenous bone graft and interspinous fixation; 3) OP-1 group: in situ posterolateral L5-L6 arthrodesis using OP-1 and 4) combined OP-1 and fixation group. Radiographic fusion analysis was performed with computed tomography scans at 3 and 12 weeks after surgery. Decalcified histology was performed to assess tissue morphology and cellularity. RESULTS: Minimal evidence of fusion was noted at 3 weeks with autograft or OP-1. By 12 weeks, all OP-1-treated animals had solid fusion, whereas no fusion was noted in autograft animals. The addition of fixation slightly increased radiographic fusion at 3 weeks in autograft and OP-1 groups but did not affect OP-1 animals at 12 weeks where all were fused. Decalcified histologic results confirmed the proliferative bone formation noted with OP-1 and the variable cellular response with autograft. CONCLUSIONS: The results of the present study suggest that the osteoinductive effect of OP-1 may be only minimally enhanced early in the bone healing process but does not appear to be affected in the long term by spinal fixation in the rabbit intertransverse fusion model. Fixation appeared to enhance early fusion in the autograft group.