JVD 2016 deck Flashcards
According to “Bridging plate development for Tx of segmental bone defects of the canine mandible: mechanical tests and finite element method” by Perez de Freitas, Melchert et al, what are some causes of mandibular segmental defects? What are the goals of reconstructive treatment?
trauma, ballistic projectiles, severe perio, mandibulectomy (tumor, other); goals: reestablish bone continuity, obtain appropriate dental occlusion (prevent drift), and restore functional aspects
According to “Bridging plate development for Tx of segmental bone defects of the canine mandible: mechanical tests and finite element method” by Perez de Freitas, Melchert et al, what are the most common implants used for mandibular reconstruction? where are they typically placed? Where is the tensile zone of the mandible?
bone plates and screws (could also use in conjunction w BMPs– not mentioned); placed on ventral aspect of mandible to stabilize segments and preserve facial contour and occlusion and stabilize bone grafts; tensile surface is dorsal aspect
According to “Bridging plate development for Tx of segmental bone defects of the canine mandible: mechanical tests and finite element method” by Perez de Freitas, Melchert et al, what is the complication with the location of the tensile zone of the mandible (why can’t it be used)?
dorsal aspect of mandible; tooth roots and mandibular canal may be in the way
According to “Bridging plate development for Tx of segmental bone defects of the canine mandible: mechanical tests and finite element method” by Perez de Freitas, Melchert et al, briefly explain the study design.
4 healthy dogs (Rottie, Dobie, Boxer, Mini poodle) used as models through helical CT and 3D models made. 6 mandibular prototypes made for each dog breed (4) with a segmental bone defect in the right mandible at the level of the first molar (409). Bridging plate and cortical locking screws designed. Force used in finite element method to calculuate plate resistance to bite forces was based on previously recorded body mass bite forces. Plates were made of titanium and mono cortical locking screws 4 on either side of defect (diff sizes for diff breeds). Screws placed buccal cortical bone body midway to avoid tooth roots/canal. Cantilever bending performed on 20 mandible prototypes with load applied to fourth premolar tooth.
According to “Bridging plate development for Tx of segmental bone defects of the canine mandible: mechanical tests and finite element method” by Perez de Freitas, Melchert et al, what were the results in regard to fracture of the left mandible in each breed?
Rotties and Dobies had all left mandibles fx in caudal portion with no evidence of plate fracture or screw failure. All but one boxer mandible fractured in left caudal mandible; no fracture of bone plate, 1 had locking screw caudal to defect pullout, 1 bending of bridging plate. Mini poodles all left mandibles had fracture caudally, all bridging plates bended, pullouts locking screws caudal to defect in all.
According to “Bridging plate development for Tx of segmental bone defects of the canine mandible: mechanical tests and finite element method” by Perez de Freitas, Melchert et al, in regards to maximum forces, deflection, and relative rigidity for each breed was there statistical significance?
Max force: no sig difference btwn Dobie and Rottie, btwn Dobie and boxer, WAS sig difference btwn boxer and Rottie. Max deflection: no sig diff btwn Rottie, Dobie, Boxer. Relative rigidity: no sig difference btwn Dobbie and Rottie, WAS sig difference btwn Dobie and Boxer and btwn Boxer and Rottie.
According to “Bridging plate development for Tx of segmental bone defects of the canine mandible: mechanical tests and finite element method” by Perez de Freitas, Melchert et al, for medium and large breed dogs where was the highest force concentration on the plate? small breed dogs?
caudal portion of bridging plate with screws 1/4 with most demand. Central portion of bridging plate.
According to “Bridging plate development for Tx of segmental bone defects of the canine mandible: mechanical tests and finite element method” by Perez de Freitas, Melchert et al, where did 85% of all fractures occur? what was less rigid: left mandible or plate mandible system?
caudal mandibular body of left mandibles; plate mandible system was less rigid than left mandible, hence, fractures of the left mandible.
According to “Bridging plate development for Tx of segmental bone defects of the canine mandible: mechanical tests and finite element method” by Perez de Freitas, Melchert et al, overall what was seen in medium/large breed dogs? small breed dogs? in response to bending forces
Med/Lg breed: fractured left mandible with no fracture of plate and mostly no pullout of locking screws. Small breed: fx of left mandible, deformation and pullout of locking screws in caudal portion of plate.
According to “Bridging plate development for Tx of segmental bone defects of the canine mandible: mechanical tests and finite element method” by Perez de Freitas, Melchert et al, what is the theory for why small breed dogs had pullout of locking screws, deformation of plate and left mandibular fx?
less thick cortical bone in relation to larger breeds.
According to “Bridging plate development for Tx of segmental bone defects of the canine mandible: mechanical tests and finite element method” by Perez de Freitas, Melchert et al, what is responsible for the forces being applied to the caudal portion of the plate?
masticatory forces
According to “Bridging plate development for Tx of segmental bone defects of the canine mandible: mechanical tests and finite element method” by Perez de Freitas, Melchert et al, what were some limitations of this study?
cannot generalize for all breeds; mechanical properties of model diff than real bone; placement of bone plate maybe unrealistic to prevent trauma to tooth roots/mandibular canal w/o shorter mono cortical screws
According to “Bridging plate development for Tx of segmental bone defects of the canine mandible: mechanical tests and finite element method” by Perez de Freitas, Melchert et al, was the bridging plate overall able to support bite force for each evaluated dog?
Yes; at least 5x (more in certain breeds).
According to “Measuring Rabbit (Oryctolagus cuniculus) tooth growth and eruption by fluorescence markers and bur marks” by Wyss, Hatt et al, what is meant by the term hystricomorph rodents? what type of teeth do these rodents and lagomorphs have?
means rodents with zygomassenteric specialization, hyposodont. elodont, aradicular teeth (all teeth, unlike other rodents with closed premolars/molars), ex are porcupine, chinchillas, GPs, capybaras; lagamorphs are hypsodont, elodont, aradicular.
According to “Measuring Rabbit (Oryctolagus cuniculus) tooth growth and eruption by fluorescence markers and bur marks” by Wyss, Hatt et al, what 3 types of diagnostics were performed to measure tooth growth?
Manual bur marks on teeth, CT for apical to coronal measurement, and fluorescence microscopic images of teeth
According to “Measuring Rabbit (Oryctolagus cuniculus) tooth growth and eruption by fluorescence markers and bur marks” by Wyss, Hatt et al, what were the 2 fluorescence markers used? what were the 2 groups of rabbits and on what days were the analyses performed?
6 rabbits; 3 on all grass hay, 3 on grass, rice hull pellets and sand; 2-5d post diet change SQ injection of calcein green; 10d later SQ injection xylenol orange.
According to “Measuring Rabbit (Oryctolagus cuniculus) tooth growth and eruption by fluorescence markers and bur marks” by Wyss, Hatt et al, was there correlation btwn the different modalities?
Sig correlation btwn manual and CT measurements.
According to “Measuring Rabbit (Oryctolagus cuniculus) tooth growth and eruption by fluorescence markers and bur marks” by Wyss, Hatt et al, were the authors able to draw any conclusions regarding overall growth/eruption and diet?
No due to small sample size. Anecdotally, rabbits in hay groups had a slower more normal growth rate.
According to JVD Spring 2016, Treatment of Bignathic Malocclusions With Multistage Active Force Orthodontic Movements in a Cat,
What are the recommended forces for tipping a tooth?
35-60gm
According to JVD Spring 2016, Treatment of Bignathic Malocclusions With Multistage Active Force Orthodontic Movements in a Cat,
What is commonly recommended in the veterinary literature to activate an elastic force device?
Reduce at rest length by 25%
According to Quantification of Canine Dental Plaque Using Quantitative Light-Induced Fluorescence,
According to the VOHC, how much difference in plaque accumulation must be seen to consider a treatment effective?
15%
According to Quantification of Canine Dental Plaque Using Quantitative Light-Induced Fluorescence
What are currently accepted plaque quantification methods and what is their premise?
Logan boyce – accumulation of plaque on the entire buccal surface of a tooth scored 1-4
GCPI percentage of gingival margin with plaque measured with a special gingival margin probe on select teeth, averaged out to give a score for the mouth
According to Quantification of Canine Dental Plaque Using Quantitative Light-Induced Fluorescence,
Which teeth are included by the VOHC for scoring of plaque products?
Maxillary I3, C, P3, P4, M1, and mandibular C, P3, P4, M1
According to Quantification of Canine Dental Plaque Using Quantitative Light-Induced Fluorescence
Which teeth showed the most variability?
P1 and P2, but they had the lowest level of plaque coverage.