Objective—To determine the prevalence of tooth resorption in dogs and to evaluate whether a classification system for tooth resorption in humans is applicable in this species.
Animals—224 dogs > 1 year old admitted for periodontal treatment or other dental procedures in 2007
Procedures—Full-mouth radiographs of all dogs were reviewed for evidence of tooth resorption. Tooth resorption was classified in accordance with radiographic criteria described for use in humans. Patient signalment and concurrent dental conditions were recorded and tabulated.
Results—Tooth resorption was detected in 120 of 224 (53.6%) dogs and 943 of 8,478 (11.1%) teeth. The classification system for use in humans was applicable in 908 of 943 (96.3%) affected teeth. Tooth resorption was more frequent among older and large-breed dogs; no significant differences were found among sex categories. The 2 most common types of tooth resorption were external replacement resorption (77/224 [34.4%] dogs and 736/8,478 [8.7%] teeth) and external inflammatory resorption (58/224 [25.9%] dogs and 121/8,478 [1.4%] teeth). External cervical root surface resorption was detected in 13 of 224 (5.8%) dogs; external surface resorption was detected in 10 of 224 (4.5%) dogs, and internal inflammatory resorption and internal surface resorption were detected in 9 of 224 (4.0%) and 1 of 224 (0.4%) dogs, respectively. Internal replacement resorption was not detected.
Conclusions and Clinical Relevance—The classification of tooth resorption in humans was applicable to tooth resorption in dogs. Resorption lesions, in general, and external replacement and external inflammatory resorption, in particular, were frequently detected in dogs.
Objective—To determine applicability of the 2007 American Veterinary Dental College (AVDC) classification method for determining extent of tooth resorption in dogs.
Animals—224 dogs > 1 year old admitted for periodontal treatment or other dental procedures in 2007.
Procedures—Full-mouth radiographs of all dogs were reviewed for evidence of tooth resorption. Tooth resorption in dogs was classified in accordance with the radiographic criteria described for use in human teeth and, when applicable, the guidelines described in the 2007 AVDC classification method.
Results—851 of 943 (90.2%) affected teeth met the radiographic characteristics of 1 of the 5 stages of tooth resorption described by the AVDC classification method. Among tooth resorption types described for human teeth, the AVDC classification method was totally applicable (100%) in 17 teeth with external surface resorption, 21 teeth with external replacement resorption, and 736 teeth with external cervical root surface resorption, but it was applicable in only 56 of 121 (46.3%) teeth with external inflammatory resorption and none of the teeth with internal resorption.
Conclusions and Clinical Relevance—The AVDC classification method was useful to describe the extent of tooth resorption in dogs, but it did not reflect the radiographic patterns and location of lesions. The AVDC classification method was applicable in some, but not all, of the teeth with various resorption types in dogs. The AVDC classification method could be adapted best to lesions that have radiographic patterns of external replacement resorption and external cervical root surface resorption.
Objective—To determine the diagnostic value of 2
intraoral bisecting angle radiographic views in comparison
with periodontal probing for the assessment
of periodontal attachment of the canine teeth in dogs.
Study Population—466 canine teeth from 117 dogs.
Procedure—Periodontal probing measurements
were recorded, and clinical attachment levels (CAL)
were calculated at the mesial, buccal, distal, and lingual
(or palatal) surfaces on each canine tooth.
Occlusal and lateral radiographs of the canine teeth
were obtained. Alveolar margin height (AMH) was
measured at the same 4 surfaces. Values for AMH
and CAL were compared on the basis of tooth surface,
dental arch, and radiographic view.
Results—The AMH at the mesial and distal surfaces of
the mandibular canine teeth was measurable on the
lateral view and was significantly correlated with CAL.
Similar results were found for the mesial and distal surfaces
of the maxillary canine teeth. Buccal and lingual
AMH were measured on the mandibular occlusal radiographic
view, and values were significantly correlated
with CAL, but only the buccal AMH could be assessed
on the occlusal radiographic view of the maxilla with
values that correlated significantly with CAL.
Conclusions and Clinical Relevance—The lateral
radiographic view is suitable for evaluating periodontal
attachment at the mesial and distal surfaces of the
canine teeth in dogs. The occlusal radiographic view is
suitable for assessing buccal surfaces as well as the
lingual surface of mandibular canine teeth but not the
palatal surface of maxillary canine teeth in dogs. (Am J Vet Res 2003;64:255–261)
Objective—To determine elemental composition of
teeth with and without odontoclastic resorption
lesions (ORL) in cats.
Sample Population—Normal teeth from 22 cadaver
cats and ORL-affected teeth from 21 cats admitted to
the veterinary hospital for dental treatment.
Procedure—An electron microprobe was used to
analyze weight percentages of calcium, phosphorus,
fluorine, sodium, magnesium, sulfur, potassium, and
iron in enamel, dentin, and cementum.
Results—Calcium and phosphorus were the most
abundant elements. Fluorine, sodium, and magnesium
combined were < 5% and sulfur, potassium,
and iron combined were < 0.1% of total elemental
composition. In enamel of normal teeth, a significant
sex-by-jaw location interaction was seen in mean
(± SD) phosphorus content, which was higher in
mandibular teeth of females (17.64 ± 0.41%) but
lower in mandibular teeth of males (16.71 ± 0.83%).
Mean iron content in dentin of normal teeth was significantly
lower in mandibular teeth than maxillary
teeth (0.014 ± 0.005% vs 0.023 ± 0.019%). Mean
enamel sodium content was significantly higher
(0.77 ± 0.046% vs 0.74 ± 0.025) and mean enamel
iron content was significantly lower (0.017 ± 0.008%
vs 0.021 ± 0.005%) in ORL-affected teeth, compared
with normal teeth. In cementum, mean fluorine content
was significantly lower (2.98% ± 0.27 vs 2.99 ±
0.20%) and mean magnesium content was significantly
lower (0.54 ± 0.13% vs 0.60 ± 0.13%) in ORLaffected
teeth, compared with normal teeth.
Conclusions and Clinical Relevance—Results of our
study establish baseline mineral content of enamel,
dentin, and cementum for normal teeth in cats.
Minimal differences in mineral content of enamel and
cementum of normal and ORL-affected teeth were
detected. (Am J Vet Res 2002;63:546–550)
OBJECTIVE To systematically characterize the morphology of cleft lip, cleft palate, and cleft lip and palate in dogs.
ANIMALS 32 client-owned dogs with clefts of the lip (n = 5), palate (23), or both (4) that had undergone a CT or cone-beam CT scan of the head prior to any surgical procedures involving the oral cavity or face.
PROCEDURES Dog signalment and skull type were recorded. The anatomic form of each defect was characterized by use of a widely used human oral-cleft classification system on the basis of CT findings and clinical images. Other defect morphological features, including shape, relative size, facial symmetry, and vomer involvement, were also recorded.
RESULTS 9 anatomic forms of cleft were identified. Two anatomic forms were identified in the 23 dogs with cleft palate, in which differences in defect shape and size as well as vomer abnormalities were also evident. Seven anatomic forms were observed in 9 dogs with cleft lip or cleft lip and palate, and most of these dogs had incisive bone abnormalities and facial asymmetry.
CONCLUSIONS AND CLINICAL RELEVANCE The morphological features of congenitally acquired cleft lip, cleft palate, and cleft lip and palate were complex and varied among dogs. The features identified here may be useful for surgical planning, developing of clinical coding schemes, or informing genetic, embryological, or clinical research into birth defects in dogs and other species.
OBJECTIVE To compare the biomechanical behavior of mandibular critical-sized defects stabilized with 2 plating configurations under in vitro conditions resembling clinical situations.
SAMPLE 24 mandibles harvested from 12 adult canine cadavers.
PROCEDURES 8 mandibles were kept intact as control samples. A critical-sized defect was created in 16 mandibles; these mandibles were stabilized by use of a single locking plate (LP [n = 8]) or an LP combined with an alveolar miniplate (LMP ). Mandibles were loaded in cantilever bending in a single-load-to-failure test with simultaneous recording of load and actuator displacement. Stiffness, yield, and failure properties were compared among groups. Mode of failure was recorded. Radiographic evidence of tooth root and mandibular canal damage was quantified and compared between groups.
RESULTS Stiffness and yield loads of single LP and LMP constructs were < 30% of values for intact mandibles, and failure loads were < 45% of values for intact mandibles. There were no consistent biomechanical differences at failure between single LP and LMP constructs, but the LMP construct had greater stiffness and strength prior to yield. Frequency of screw penetration of teeth and the mandibular canal was significantly greater for LMP than for single LP constructs.
CONCLUSIONS AND CLINICAL RELEVANCE Both fixation methods were mechanically inferior to an intact mandible. The LMP construct was mechanically stronger than the LP construct but may not be clinically justifiable. Addition of an alveolar miniplate provided additional strength to the construct but resulted in more frequent penetration of tooth roots and the mandibular canal.
OBJECTIVE To evaluate biomechanical properties of intact feline mandibles, compared with those for mandibles with an experimentally created osteotomy that was stabilized with 1 of 2 internal fixation configurations.
SAMPLE 20 mandibles from 10 adult feline cadavers.
PROCEDURES An incomplete block study design was used to assign the mandibles of each cadaver to 2 of 3 groups (locking plate with locking screws [locking construct], locking plate with nonlocking screws [nonlocking construct], or intact). Within each cadaver, mandibles were randomly assigned to the assigned treatments. For mandibles assigned to the locking and nonlocking constructs, a simple transverse osteotomy was created caudal to the mandibular first molar tooth after plate application. All mandibles were loaded in cantilever bending in a single-load-to-failure test while simultaneously recording load and actuator displacement. Mode of failure (bone or plate failure) was recorded, and radiographic evidence of tooth root and mandibular canal damage was evaluated. Mechanical properties were compared among the 3 groups.
RESULTS Stiffness, bending moments, and most post-yield energies for mandibles with the locking and nonlocking constructs were significantly lower than those for intact mandibles. Peak bending moment and stiffness for mandibles with the locking construct were significantly greater than those for mandibles with the nonlocking construct. Mode of failure and frequency of screw damage to tooth roots and the mandibular canal did not differ between the locking and nonlocking constructs.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that both fixation constructs were mechanically inferior to intact mandibles. The locking construct was mechanically stronger than the nonlocking construct.
Objective—To develop a computer-assisted image
analysis procedure for quantitation of neovascularization
in formalin-fixed paraffin-embedded specimens
of thyroid gland tissue from dogs with and
without thyroid gland neoplasia.
Sample Population—47 thyroid gland carcinomas,
8 thyroid gland adenomas, and 8 specimens of thyroid
tissue from dogs without thyroid gland abnormalities
Procedure—Serial tissue sections were prepared
and stained with antibodies against human CD31 or
factor VIII-related antigen (factor VIII-rag). The areas
of highest vascularity were identified in CD31-
stained sections, and corresponding areas were
then identified in factor VIII-rag-stained sections.
Image analysis was used to calculate the total vascular
density in each section, and neovascularization,
expressed as a percentage, was determined
as the absolute value of the total vascular density
derived from factor VIII-rag-stained sections minus
the vascular density derived from CD31-stained
Results—Mean vascular density of thyroid gland
carcinomas derived from CD31-stained sections
was significantly greater than density derived from
factor VIII-rag-stained sections. This incremental difference
was presumed to represent degree of neovascularization.
However, significant differences
were not detected between vascular densities
derived from CD31 and factor VIII-rag-stained sections
for either normal thyroid gland tissue or thyroid
gland adenomas. No significant correlations
were found between vascular density in thyroid
gland carcinomas and survival time following
Conclusion and Clinical Relevance—A computerassisted
image analysis method was developed for
quantifying neovascularization in thyroid gland
tumors of dogs. This method may allow identification
of dogs with tumors that are most likely to
respond to treatment with novel antiangiogenesis
agents. (Am J Vet Res 2002;63:363–369)
To evaluate and quantify the kinematic behavior of canine mandibles before and after bilateral rostral or unilateral segmental mandibulectomy as well as after mandibular reconstruction with a locking reconstruction plate in ex vivo conditions.
Head specimens from cadavers of 16 dogs (range in body weight, 30 to 35 kg).
Specimens were assigned to undergo unilateral segmental (n = 8) or bilateral rostral (8) mandibulectomy and then mandibular reconstruction by internal fixation with locking plates. Kinematic markers were attached to each specimen in a custom-built load frame. Markers were tracked in 3-D space during standardized loading conditions, and mandibular motions were quantified. Differences in mandibular range of motion among 3 experimental conditions (before mandibulectomy [ie, with mandibles intact], after mandibulectomy, and after reconstruction) were assessed by means of repeated-measures ANOVA.
Both unilateral segmental and bilateral rostral mandibulectomy resulted in significantly greater mandibular motion and instability, compared with results for intact mandibles. No significant differences in motion were detected between mandibles reconstructed after unilateral segmental mandibulectomy and intact mandibles. Similarly, the motion of mandibles reconstructed after rostral mandibulectomy was no different from that of intact mandibles, except in the lateral direction.
CONCLUSIONS AND CLINICAL RELEVANCE
Mandibular kinematics in head specimens from canine cadavers were significantly altered after unilateral segmental and bilateral rostral mandibulectomy. These alterations were corrected after mandibular reconstruction with locking reconstruction plates. Findings reinforced the clinical observations of the beneficial effect of reconstruction on mandibular function and the need for reconstructive surgery after mandibulectomy in dogs.
To evaluate the biomechanical properties of the mandibles of cats with experimentally created osteotomies simulating oblique ramus fractures, which were stabilized with malleable L-miniplates with either locking screws [locking construct (LC)] or nonlocking screws [nonlocking construct (NLC)], compared with those for intact mandibles.
20 mandibles from 10 adult cat cadavers.
A block study design was adopted to allocate the mandibles of each cadaver to 2 of the 3 test groups (LC, NLC, or intact mandible). Mandibles within each cadaver were allocated systematically to a test group. For mandibles assigned to an LC and an NLC, a complete oblique osteotomy was performed from the mid rostral aspect of the ramus in a caudoventral direction. All mandibles were loaded in a single-load-to-failure test through cantilever bending. Load and actuator displacement were recorded simultaneously. Mode of failure and radiographic evidence of damage to tooth roots and the mandibular canal were evaluated. Biomechanical properties were compared among the groups.
No iatrogenic tooth root damage was evident, but all mandibles with an LC and an NLC had evidence of screw invasion into the mandibular canal. Plated mandibles had significantly less stiffness and bending moment than intact mandibles. Stiffness was not significantly different between the LC and the NLC; the NLC had a greater bending moment at failure than the LC. The pre-yield stiffness of plated mandibles decreased when the number of screw holes overlapping the mandibular canal increased.
The use of a malleable L-miniplate in a caudal mandibular fracture model is feasible. Both the LC and the NLC were inferior mechanically to intact mandibles. Type of construct used did not affect the construct stiffness significantly in tested mandibles.