Anatomy and Development

Question 1

In Schrock’s 2013 study “Three-dimensional anatomy of equine incisors: tooth length, enamel cover and age related changes,” equine incisors reach their maximum length how many years post eruption, and after what tooth age does the tooth length start to decrease rapidly?

Staszyk BMC Veterinary Research 2013

Answer 1

Maximum length 2-4 years
decrease rapidly after 13-15 years

Question 2

In Schrock’s 2013 study “Three-dimensional anatomy of equine incisors: tooth length, enamel cover and age related changes,” identations are present in the enamel of what surfaces of the teeth, and enamel reaches further apically on the labial or palatal sides of the teeth?

Staszyk BMC Veterinary Research 2013

Answer 2

Indentations: mesial and distal
Enamel reaches further on labial surface

Question 3

In Schrock’s 2013 study “Three-dimensional anatomy of equine incisors: tooth length, enamel cover and age related changes,” what incisors are stat sig longer than the others in the upper and lower quadrants respectively?

Staszyk BMC Veterinary Research 2013

Answer 3

Upper: middle
Lower: corner

Question 4

In Sahara’s 2014 paper “Development of Coronal Cementum in Hypsodont Horse Cheek Teeth,” this image of a mandibular fourth premolar occlusal surface is most consistent with what age horse?

The Anatomical Record 2014

Answer 4

3.5 years

Question 5

In Sahara’s 2014 paper “Development of Coronal Cementum in Hypsodont Horse Cheek Teeth,” how was the resorption of enamel evaluated with histochemistry?

Answer 5

tartrate-resistant acid phosphatase (TRAP) activity as a marker for odontoclasts and their precursors using the azo-dye method

Study showed for the first time that prior to coronal cementogenesis TRAP-positive odontoclasts resorbed the enamel surface of the reserve crown in horse cheek teeth

Question 6

In Sahara’s 2014 paper “Development of Coronal Cementum in Hypsodont Horse Cheek Teeth,” what are the structural composition differences between infolding and peripheral cementum?

Answer 6

Infolding cementum: free from extrinsic collagen fibers (Sharpey’s fibers), cellular with abundant blood vessels, maintains occlusal surface
Peripheral cementum: contains Sharpey’s fibers and provides anchorage for PDL, tertiary cementum thickest in subgingival region

Secondary and tertiary cementum provides sites for insertion of the PDL

Question 7

In Omura’s 2015 paper “Measurement of Incisor Overjet and Physiological Diastemata Parameters in Quarter Horse Foals,” maximum growth of the maxillary and mandibular diastemata occured in what age group?

JVD 2015

Answer 7

4-5 months old

Question 8

In Omura’s 2015 paper “Measurement of Incisor Overjet and Physiological Diastemata Parameters in Quarter Horse Foals,” overjets were most common in what sex of Quarter horses of what lineage?

JVD 2015

Answer 8

female Quarter horses of show lineage

Question 9

In Iacopetti’s 2015 article on the mandibular nerve, in 95% (38 horses) of the subjects examined, the nerve changes direction between which roots of which teeth?

Anat Histol Embryology 2015

Answer 9

mesial root of M1 and the distal root of PM4

In the remaining 5% of the subjects examined (2 horses), a variation was found in the course of the nerve at this site → the IAN runs lingually and coronally as described above, but passes between the distal and the mesial roots of PM4 instead

Question 10

In Suske et al’s paper “Infundibula of equine maxillary cheek teeth. Part 1: Development, blood supply and infundibular cementogenesis”, which cheek tooth infundibula has blood supply for longer in development?

The Vet Journal 2016

Answer 10

Distal infundibulum

Equine infundibula are assumed to represent extreme deep and large pits in between enamel cusps
According to this concept, the enamel organ invaginates from an occlusal direction and produces the infundibular enamel
Consequently, the dental follicle tissues (including blood vessels) have to follow the occlusal route to initiate the onset of infundibular cementogenesis.
After tooth eruption the afferent blood vessels are assumed to have been destroyed and therefore cementogenesis immediately stops

Question 11

According to Dixon 2010 what is the range of distance between between the occlusal surface and pulp tissue (depth of subocclusal secondary dentin) in a 4 year old vs 16 year old horse?

Answer 11

4 yro: 5-33mm
16 yro: 2-24mm

Question 13

In Listmann’s 2017 paper “Occlusal Angles of Equine Incisors,” what significant differences in the left and right sides were observed for teeth in same triaden position and the jaws themselves respectively?

JVD 2017, Issue 4, Staszyk

Answer 13

No stat sig differences in angles for same triaden teeth positions right to left
Marked differences between left and right sides of upper and lower jaws

Question 14

In Listmann’s 2017 paper “Occlusal Angles of Equine Incisors,” were the upper or lower bars most suitable to determine incisor angulations?

JVD 2017, Issue 4, Staszyk

Answer 14

Lower bars due to relatively straight profile vs curve of maxillary bars and facial crest

The TMJ and eyeball were not useful reference points

Question 15

In Hole’s 2016 study “Dimensions of 65 Extracted Equine First Premolar Teeth,” what were the correlations between crown height and root length and total length?

JVD 2016

Answer 15

Crown height and crown width were either not correlated or poorly correlated with root length
Crown height was poorly correlated with total length

Question 16

In Hole’s 2016 study “Dimensions of 65 Extracted Equine First Premolar Teeth,” what measurements were statistically significantly correlated?

JVD 2016

Answer 16

Total tooth length was correlated with root length

Question 17

In Hole’s 2016 study “Dimensions of 65 Extracted Equine First Premolar Teeth,” what was the median total length and median root length?

JVD 2016

Answer 17

Median total length: 21mm
Median root length: 13mm

Question 18

In Englisch’s 2018 paper “Anatomy of equine incisors: Pulp horns and subocclusal dentine thickness”, what was the subocclusal dentine thickness range for upper and lower incisors

EVJ 2018

Answer 18

1.5 and 11.7 mm in upper
0.7 and 6.7 mm in lower incisors.

Question 19

In Englisch’s 2018 paper “Anatomy of equine incisors: Pulp horns and subocclusal dentine thickness”, what variations of pulp horns were present anatomically in the incisors?

EVJ 2018

Answer 19

1-2 pulp horns, labiomesial and labiodistal

Majority of upper incisors (≥65%) featured both a labiomesial and a labiodistal pulp horn.
Lower central (301/401) and middle incisors (302/402) showed the same prevalence (≥65%) of the two pulp horns.
All lower corner incisors (303/403) only the labiomesial pulp horn was present.
Almost all incisors (97%) featuring only one single pulp horn possessed the labiomesial pulp horn

Question 20

In Poschke’s 2018 study “Molecular Characteristics of the Equine Periodontal Ligament,” what tendon molecular components were significantly higher in mature PDL tissue vs mature tendon tissue?

Staszyk, Frontiers 2018

Answer 20

COL1, COL3

Question 21

In Poschke’s 2018 study “Molecular Characteristics of the Equine Periodontal Ligament,” what was the ratio between mean relative COL1 and COL3 gene expression for mature equine PDL?

Staszyk, Frontiers 2018

Answer 21

3:3:1

Question 22

In Horbal’s 2019 paper “A Computed Tomographic (CT) and Pathological Study of Equine Cheek Teeth Infundibulae Extracted From Asymptomatic Horses. Part 1: Prevalence, Type and Location of Infundibular Lesions on CT Imaging” which max cheek tooth infundibulum was more frequently affected by occlusal caries? Which triadan position?

Frontiers 2019

Answer 22

Rostral infundibulum
09s

The rostral infundibulae were significantly more frequently affected by higher grades of caries than the caudal infundibulae

Question 23

In Horbal’s 2019 paper “A Computed Tomographic (CT) and Pathological Study of Equine Cheek Teeth Infundibulae Extracted From Asymptomatic Horses. Part 1: Prevalence, Type and Location of Infundibular Lesions on CT Imaging” of 200 infundibulae examined by standard CT, how many had some form of subocclusal cemental lesion?

Frontiers 2019

Answer 23

182 (91%)

Question 24

In Horbal’s 2019 paper “A Computed Tomographic (CT) and Pathological Study of Equine Cheek Teeth Infundibulae Extracted From Asymptomatic Horses. Part 1: Prevalence, Type and Location of Infundibular Lesions on CT Imaging” what percent of infundibulae without occlusal caries had subocclusal developmental infundibular lesions?

Frontiers 2019

Answer 24

72% of infundibulae without occlusal caries

Question 25

In Tanner’s 2019 study “A Retrospective Study of the Prevalence of First Premolars in 306 Thoroughbred Yearlings,” what overall percent of horses had erupted maxillary first premolars at the time of examination and what was the average age?

JVD 2019

Answer 25

73% erupted maxillary first premolars
Average age at time of examination 15 months

Question 26

In Tanner’s 2019 study “A Retrospective Study of the Prevalence of First Premolars in 306 Thoroughbred Yearlings,” horses less than or equal to 13 months old and greater than or equal to 18 months old had what prevalence of erupted maxillary first premolars?

Answer 26

< 13 months old 50% prevalence
> 18 months old 90%

20-23 months old 100%

Question 27

In Tanner’s 2019 study “A Retrospective Study of the Prevalence of First Premolars in 306 Thoroughbred Yearlings,” what percent of males vs females had erupted first premolars?

JVD 2019

Answer 27

Males 67%
Females 77%

stat sig fewer males than females

Question 28

In Tanner’s 2019 study “A Retrospective Study of the Prevalence of First Premolars in 306 Thoroughbred Yearlings,” what age was the eruption age of maxillary first premolars in TBs suggested to be lengthened to?

Answer 28

18 months (present in 90%)

Question 29

What developmental disorder is depicted?

EVE 2020 Dixon

Answer 29

Dental dysplasia

abnormal buccal protrusion composed mainly of dentine and peripheral enamel

Question 30

What developmental disorder is depicted here?

EVE 2020 Dixon

Answer 30

Dental dysplasia

No infundibulum, abnormal distribution of pulp horns

More prone to central wear with no INF

Question 31

What is the most common supernumerary tooth in the horse? Least common?

EVE 2020 Dixon

Answer 31

Incisors are most common
Maxillary cheek teeth > mandibular cheek teeth

Question 32

What is the least common dental disorder in the horse?

EVE 2020 Dixon

Answer 32

Hypodontia or anodontia is the rarest equine dental developmental disorder with a prevalence of 0.25% in one study of 400 horses (Dixon et al. 1999).

Question 33

In Domanska-Kruppa’s 2019 study “Cephalometric Study of the Overjet Development in Warmblood Foals,” what percent of foals evaluated had a overjet, what percent of those foals had spontaneous regression of incisor misalignment, and what percent of control foals developed an overjet?

Frontiers 2019

Answer 33

2% (13/650) foals had an overjet
69% (9/13) spontaneous regression
31% (4/13) control foals developed overjet

Question 34

In Domanska-Kruppa’s 2019 study “Cephalometric Study of the Overjet Development in Warmblood Foals,” what two ratios were useful to determine whether a foal born with physiological incisor alignment would develop overjet?

Frontiers 2019

Answer 34

PiMx/PiMn, Mna/ML

Question 35

In Domanska-Kruppa’s 2019 study “Cephalometric Study of the Overjet Development in Warmblood Foals,” did short or long lines have improved accuracy and what were the most accurate measurements?

Frontiers 2019

Answer 35

Long lines improved accuracy
most accurate measurements: FL-facial, EtL-ethmoidal cephalometric lines

Question 36

In Kau’s 2020 paper “Computed Tomography (CT)-Assisted 3D Cephalometry in Horses: Interincisal Angulation of Clinical Crowns,” which of the following is most correct?

A) Regardless of tooth position, tooth generation, or age, the majority of examined horses showed an acute interincisal angle.
B) A non-linear age-related angle decline most distinctive in first incisor length was shown
C) Period of greatest decrease in clinical crown IIA < 13-15 years had constant tooth length ratios
D) Age estimate based on the interincisal angle of clinical crowns was recommended by the authors

Frontiers 2020

Answer 36

C) Period of greatest decrease in clinical crown IIA < 13-15 years had constant tooth length ratios

A) obtuse interincisal angle
B) third incisor length was shown
D) age estimates NOT recommended

Question 37

In Kau’s 2020 paper “Computed Tomography (CT)-Assisted 3D Cephalometry in Horses: Interincisal Angulation of Clinical Crowns,” what two trends were noted overall in regards to the angle?

Frontiers 2020

Answer 37

IIA (the interincisal angle) tends to approach an end value in older horses
Third incisor teeth show a significantly higher overall angle decrease compared to first and second incisors

Question 38

In Kau’s 2020 paper “Computed Tomography (CT)-Assisted 3D Cephalometry in Horses: Interincisal Angulation of Clinical Crowns,” can the interincisal angle determine age?

Frontiers 2020

Answer 38

No - authors do not recommend, not accurate

Question 39

Define hetertopic polydontia and dentigerous cyst

Platt JVD 2021 issue 1

Answer 39

Heterotopic polyodontia: Extra tooth outside the dental arcade. Includes dentigerous cysts in the temporal region of the horse

Dentigerous cysts Aka temporal teratoma, ear tooth, ectopic tooth or heterotopic polyodontia
Congenital abnormality that form due to premature closure of the first branchial cleft during embryologic development → ectopic dental tissue

Question 40

In Pimentel’s 2021 study “The Frequency of Communication Between the Synovial Compartments of the Equine Temporomandibular Joint: A Contrast-Enhanced Computed Tomographic Assessment” what do each arrow indicate for location of the contrast media?

Frontiers 2021

Answer 40

presence of the radiopaque contrast material in the discotemporal joint (yellow)
discomandibular joint (blue)
varying amounts outside the joints (white)

Question 41

In Pimentel’s 2021 study “The Frequency of Communication Between the Synovial Compartments of the Equine Temporomandibular Joint: A Contrast-Enhanced Computed Tomographic Assessment” what was the conclusion of the communication between compartments?

Frontiers 2021

Answer 41

No communication in non-diseased TMJs

Question 42

What characteristic was described as possibly unique to paranasal sinus cysts in Ostrowska’s 2020 EVJ paper “Computed tomography characteristics of equine paranasal sinus cysts”?

EVJ 2020

Answer 42

A discrete hyperattenuating wall-like structure was detected in the periphery of the sinus lesion in precontrast acquisition in 7/8 horses with paranasal sinus cysts.

Question 43

In Guerrero Cota’s study “Regional and disease-related differences in properties of the equine temporomandibular joint disc” what region of the disk showed the highest stiffness/strength?

Journal of Biomechanics 2019

Answer 43

Rostral region

Question 44

What is the definition of syndesmosis?

Verwilghen Vet Sciences 2022

Answer 44

A non-synovial joint
Think of the sutures between facial bones

During the fetal period, the bones of the calvaria (top of the skull) and face are formed from intramembranous ossification sites within the mesenchyme covering the brain.

Question 45

When do the facial bone sutures close?

Verwilghen Vet Sciences 2022

Answer 45

Only the frontomaxillary suture expresses complete bony fusion in horses older than 20 years.
The lacrimomaxillary and zygomaticomaxillary sutures remained at least partly filled with connective tissue even in some individuals of up to 30 years of age.

Question 46

In equine hypsodont dentition, three types of peripheral cementum are defined according to their order of appearance. What are the 3?

James EOTRH Review JVD 2022 Issue 4

Answer 46

(1) A thin primary layer is deposited directly on the peripheral enamel
(2) The second layer is the functional, thicker layer responsible for anchorage to the periodontal ligament (PDL). This layer is able to constantly remodel when triggered by the normal process of continuous tooth eruption
(3) The third layer consists of tertiary cementum that is deposited subgingivally, forming part of the clinical crown once the tooth erupts

Question 47

Enamel is comprised of what percentage of inorganic materials vs organic components and water?

Arnbjerg, 2014

Answer 47

96-98% inorganic, 2-4% organic materials and water

Question 48

Dentin is comprised of what percentage of inorganic materials vs organic components and water?

Arnbjerg, 2014

Answer 48

70% inorganic, 30% organic materials and water

Question 49

Cementum is comprised of what percentage of inorganic materials vs organic components and water?

Arnbjerg, 2014

Answer 49

65% inorganic, 35% organic materials and water

Question 50

Identify the pathology indicated by the white arrows as seen in the study by Arnbjerg in 2014

Answer 50

Irregular hypercementosis

Question 51

In Alshami’s paper “Comparison of Computed Tomography Assisted 3D Cephalometric Measurements in Straight Egyptian Arabian and Thoroughbred Horses” what were the outcomes when comparing the SEAR to the TB breeds?

Alshami 2024 JVD

Answer 51

All 9 cephalometric measurements were found to be significantly greater in TB than SEAR (P < 0.05).

For the facial line: mandibular length (FL/ML) ratios TB > SEAR (P=0.002)
For the maxillary cheek teeth length: ethmoidal line ratio (Mxa/EtL), SEAR > TB (P=0.0007).

Difference in interincisal angle may be explained by the sig difference in age between the two groups, with the SEAR group older

Question 52

The maxillary septal bullae lies ventral to what sinus?

Carmalt 2020 EVE “Intraoperative depression of the bulla of the maxillary septum as amethod of improving sinus drainage without epistaxis in horses”

Answer 52

courses rostro dorsally under the floor of the dorsal conchal sinus

Question 53

What anatomy is being removed via this frontochonal flap?

Carmalt 2020 EVE

Answer 53

Maxillary septal bullae

Question 54

What bone in the hyoid apparatus is unpaired?

Hartl. Correlated imaging of the equine hyoid apparatus using CT, micro-CT, and histology. Frontiers 2021.

Answer 54

Basihyoid

Question 55

What joint is the hyoid apparatus is a synovial joint?

Hartl. Correlated imaging of the equine hyoid apparatus using CT, micro-CT, and histology. Frontiers 2021.

Answer 55

connection of thyrohyoid bones to thyroid cartilage of layrnx

Question 56

Guttural pouch endoscopy allows examination of what portions of the hyoid apparatus?

Hartl. Correlated imaging of the equine hyoid apparatus using CT, micro-CT, and histology. Frontiers 2021.

Answer 56

proximal stylohyoid and temporohyoid joint