Determination Of Insertion Sites For Dental Implantation In The Mandibular Premolar Region Of Beagles

Objective This study aimed to measure the roots of mandibular premolars and correlative anatomical characteristics of healed mandible of beagles,trying to provide some suggestions on the determination of the safe implantation region and the selection of implants’ size for immediate or delayed dental implantation to guide the safe insertion.Methods The premolars(P1-P4)of ten male beagle dogs that aged 12 months and weighed10-12 kg were removed and measurements of the length and diameter of roots were performed by vernier micrometer.3 month later,the location of the mental foramen and canine root apex of the healed mandible were measured by vernier micrometer and CBCT.The canal-crest distance and the width of the alveolar ridge crest of 3 insertion sites in the safe implantation region that does not cover the canine teeth and mental foremen were determined.Results The results from the two measuring methods showed no statistical difference(P > 0.05).The relative anatomical measurement results of immediate implantation models showed that the length of roots increased from P1 to P4,and the diameter of the distal root of P2,P3 and P4 was slightly larger than the mesial one,and the length of the mesial root was slightly longer than the distal one.single-root:P1,the length of root(L): 7.65±0.39 mm,the diameter of root cervix(φ):2.67±0.27 mm;double-root: P2-P4,the length of mesial root(ML):8.78±0.34,9.18±0.26,11.18±0.42mm;The diameter of mesial root cervix(Mφ):2.72±0.23,3.10±0.18,4.13±0.20mm;the length of distal root(DL):8.44±0.62,8.67±0.45,10.90±0.37 mm,the diameter of distal root cervix(Dφ):3.02±0.20,3.34±0.24,4.53±0.26mm;the relative anatomical measurement results of delayed implantation models showed that the location of mental foramen and canine root apex were(28.0±2.8)% and(34.8±2.7)% of the mandibular premolar region and both seemed quite stable.The canal-crest distance and the width of the alveolar ridge crest of3 insertion sites in the safe implantation region: H1: 7.22±0.70,H2:8.19±0.73,H3: 9.16±0.67mm;W1: 5.33±0.50,W2: 5.83±0.57,W3:6.39±0.57 mm.Conclusion The P1 site is not suitable for insertion in an immediate or delayed implantation model in the mandible of beagles.The delayed implantation model in this study was set up in a safe premolar region that is between the mental foremen and the first molar.The recommended implants size: “short” length(6-10mm)or “extra-short”length(≤6mm);“narrow” diameter(3.0-3.75mm)or “extra-narrow”diameter(<3.0 mm).CBCT can be applied to the experiment of dental implantation in beagles.There is no significant difference between CBCT and vernier caliper in the results of anatomic measurement.