JVD 2019 #1 Assessment of the Role of the Mandibular First Molar Tooth in Mandibular Fracture Patterns of 29 Dogs. Scherer, Hetzel & Snyder

Question 1

Root involvement in fractures

Answer 1

55.2% distal root involvement, 34.5% mesial root and 10.3% tooth was absent

Question 2

Favorable vs unfavorable MN fractures

Answer 2

Fractures coursing in the caudodorsal (CD) direction are commonly referred to as “favorable” fractures. Fractures coursing in the caudoventral (CV) direction have been previously referred to as “unfavorable” fractures.

Question 3

How many had periodontitis?

Answer 3

7 cases (24.1%)

Six of 7 cases with radiographic evidence of periodontal disease demonstrated >50% alveolar bone loss associated with the root involved in the fracture site, while 1 of 7 cases demonstrated 25% to 50% alveolar bone loss.

Question 4

Previous studies reported MN fractures represent what % of all fractures in dogs

Answer 4

1.5-6%

Question 5

Do more MN fractures occur in dentulous or edentulous areas?

Answer 5

Dentulous areas= 85% of cases involve alveolus
Majority of open fractures (94%) in tooth-bearing region and involved roots
(Umphlet, RC, Johnson, AL. Mandibular fractures in the dog. A retrospective study of 157 cases. Vet Surg. 1990)

Question 6

Frequency of involvement of M1 in MN fx (prev studies)

Answer 6

highest incidence of fx in molar region w M1 in fx line (Kitshoff, AM, de Rooster, H, Ferreira, SM, Steenkamp, G. A retrospective study of 109 dogs with mandibular fractures. Vet Comp Orthop Traumatol. 2013)
molar region was involved in 47.1% of cases, and the first molar involved in 85.9% of these cases. (Lopes, FM, Gioso, MA, Ferro, DG, Leon-Roman, MA, Venturini, MA, Correa, HL. Oral fractures in dogs of Brazil—a retrospective study. J Vet Dent. 2005)

Question 7

propagation of mandibular fractures along M1 was also classified based on a system previously described by Schloss and Marretta

Answer 7

(A) Fracture propagation courses along the periodontal ligament space and communicates between the oral cavity and apex. (B) Fracture is associated with the coronal third of the root only. (C) Fracture compromises endodontic vascular supply at the location of the apex. (D) Fracture line courses through alveolar bone sparing the root and apical vascular supply. (E) The fracture courses through the coronal periodontal ligament space and continues through the alveolar bone sparing the apex. (F) Fracture may originate at the alveolar margin by the tooth but does not course through the periodontal ligament space nor directly compromise the root.

Question 8

Fracture pattern propagation findings (caudodorsal, caudoventral or dorsoventral transverse; Buccolingual Transverse, Caudolingual, or Caudobuccal.)

Answer 8

CV in 15 (51.7%) cases, CD direction in 7 (24.1%) cases, and DVT in 7 (24.1%) cases (Dorsoventral Transverse, Caudoventral, or Caudodorsal.)

When CT imaging was available, the buccolingual orientation was assessed and demonstrated fractures occurring in the CL direction in 12 (60%) cases (P = .022), CB in 5 (25%) cases, and BLT in 3 (15%) cases (Buccolingual Transverse, Caudolingual, or Caudobuccal.)

only 5 (17.5%) demonstrated comminution- thought to be more frequently associated with high velocity injuries.

Question 9

Etiology of fractures of involving

1 Distal root

2 Mesial root

Answer 9

mesial root 38.5% of cases=

animal-on-animal contact 6 (60%) cases and inanimate objects or falls were related to 4 (40%) fractures

distal root 61.5% of the cases=

10 (62.5%) due to animal on animal contact, 2 (12.5%) fractures due to inanimate object, 1 (6.3%) fracture due to motor vehicle accident, and 3 (18.8%) cases were categorized as pathologic fractures