Anatomy and Development Flashcards
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
Maximum length 2-4 years
decrease rapidly after 13-15 years
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
Indentations: mesial and distal
Enamel reaches further on labial surface
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
Upper: middle
Lower: corner
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
3.5 years
In Sahara’s 2014 paper “Development of Coronal Cementum in Hypsodont Horse Cheek Teeth,” how was the resorption of enamel evaluated with histochemistry?
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
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?
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
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
4-5 months old
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
female Quarter horses of show lineage
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
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
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
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
According to White and 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?
4 yro: 5-33mm
16 yro: 2-24mm
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
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
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
Lower bars due to relatively straight profile vs curve of maxillary bars and facial crest
The TMJ and eyeball were not useful reference points
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
Crown height and crown width were either not correlated or poorly correlated with root length
Crown height was poorly correlated with total length
In Hole’s 2016 study “Dimensions of 65 Extracted Equine First Premolar Teeth,” what measurements were statistically significantly correlated?
JVD 2016
Total tooth length was correlated with root length
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
Median total length: 21mm
Median root length: 13mm
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
1.5 and 11.7 mm in upper
0.7 and 6.7 mm in lower incisors.
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
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
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
COL1, COL3
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
3.3:1
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
Rostral infundibulum
09s
The rostral infundibulae were significantly more frequently affected by higher grades of caries than the caudal infundibulae
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
182 (91%)
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
72% of infundibulae without occlusal caries
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
73% erupted maxillary first premolars
Average age at time of examination 15 months
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?
< 13 months old 50% prevalence
> 18 months old 90%
20-23 months old 100%
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
Males 67%
Females 77%
stat sig fewer males than females
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?
18 months (present in 90%)
What developmental disorder is depicted?
EVE 2020 Dixon
Dental dysplasia
abnormal buccal protrusion composed mainly of dentine and peripheral enamel
What developmental disorder is depicted here?
EVE 2020 Dixon
Dental dysplasia
No infundibulum, abnormal distribution of pulp horns
More prone to central wear with no INF
What is the most common supernumerary tooth in the horse? Least common?
EVE 2020 Dixon
Incisors are most common
Least common is a mand CT as Maxillary cheek teeth > mandibular cheek teeth
Of the cheek teeth, tend to be 11s
What is the least common dental disorder in the horse?
EVE 2020 Dixon
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).
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
2% (13/650) foals had an overjet
69% (9/13) spontaneous regression
31% (4/13) control foals developed overjet
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
PiMx/PiMn, Mna/ML
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
Long lines improved accuracy
most accurate measurements: FL-facial, EtL-ethmoidal cephalometric lines
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
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
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
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
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
No - authors do not recommend, not accurate
Define hetertopic polydontia and dentigerous cyst
Platt JVD 2021 issue 1
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
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
presence of the radiopaque contrast material in the discotemporal joint (yellow)
discomandibular joint (blue)
varying amounts outside the joints (white)
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
No communication in non-diseased TMJs
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
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.
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
Rostral region
The disc also exhibits increasing GAG content and compressive stiffness with increasing age
What is the definition of syndesmosis?
Verwilghen Vet Sciences 2022
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.
When do the facial bone sutures close?
Verwilghen Vet Sciences 2022
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.
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
(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
Enamel is comprised of what percentage of inorganic materials vs organic components and water?
Arnbjerg, 2014
96-98% inorganic, 2-4% organic materials and water
Dentin is comprised of what percentage of inorganic materials vs organic components and water?
Arnbjerg, 2014
70% inorganic, 30% organic materials and water
Cementum is comprised of what percentage of inorganic materials vs organic components and water?
Arnbjerg, 2014
65% inorganic, 35% organic materials and water
Identify the pathology indicated by the white arrows as seen in the study by Arnbjerg in 2014
Irregular hypercementosis
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
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
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”
courses rostro dorsally under the floor of the dorsal conchal sinus
What anatomy is being removed via this frontochonal flap?
Carmalt 2020 EVE
Maxillary septal bullae
What bone in the hyoid apparatus is unpaired?
Hartl. Correlated imaging of the equine hyoid apparatus using CT, micro-CT, and histology. Frontiers 2021.
Basihyoid
What joint in the hyoid apparatus is a synovial joint?
Hartl. Correlated imaging of the equine hyoid apparatus using CT, micro-CT, and histology. Frontiers 2021.
connection of thyrohyoid bones to thyroid cartilage of layrnx
Connections of ceratohyoid bone to epihyoid/stylo-epi when fused, and ceratohyoid to basihyoid
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.
proximal stylohyoid and temporohyoid joint
Describe the path of the maxillary division of the trigeminal nerve.
Fairburn. Computed tomographic findings in 101 horses presented for the investigation of headshaking. EVE 2022
Exits skull at round foramen and runs cranially through pyterygopalatine fossa before entering maxillary foramen and continuing through the infraorbital canal asa infraorbital nerve
In RoBgardt’s 2022 study “The equine dental pulp: analysis of the stratigraphic arrangement of the equine dental pulp in incisors and cheek teeth,” what was the association of blood vessel density with age and what zones of the pulp had the highest blood vessel density?
Vet Sci 2022
Blood vessels had an increasing trend with age in the equine dental pulp
Presence of higher density of small vessels in peripheral zones and larger vessels in central zones consistent with brachydont teeth
Teeth of aged horses possess a similar or even higher vascularity than deciduous or young teeth → high prolonged productivity
In RoBgardt’s 2022 study “The equine dental pulp: analysis of the stratigraphic arrangement of the equine dental pulp in incisors and cheek teeth,” was there evidence for the presence of a subodontoblastic nerve plexus reaching out into the dentinal tubules?
Vet Sci 2022
No
presumably because dentin is exposed at the occlusal surface by physiological wear
In RoBgardt’s 2022 study “The equine dental pulp: analysis of the stratigraphic arrangement of the equine dental pulp in incisors and cheek teeth,” was a cell free zone observed in equine teeth?
Vet Sci 2022
No
Authors propose to define a subodontoblastic supportive zone with high cellularity that shows a high capacity for dentin production even in older age
What is a “loph” structure of a tooth?
Ch 1, evolution
“loph” is a complex ridge formed between cusps as enamel is worn away
Properly label the cusps and lophs of this maxillary cheek tooth
Ch. 1 Evolution
Ch. 1 Evolution
Properly label the cusps of this mandibular cheek tooth
Ch. 1 Evolution
Which direction do secondary dentinal tubules run?
Easley Textbook, ch 25
Coronal to apical
Which of the following statements is true regarding the enamel of incisors?
A. They contain mostly type I enamel and are less resistant to wear than cheek teeth
B. They contain mostly type II enamel and are less resistant to wear than cheek teeth
C. They contain mostly type I enamel and are more resistant to wear than cheek teeth
D. They contain mostly type II enamel and are more resistant to wear than cheek teeth
Easley Textbook, ch 25
B. They contain mostly type II enamel and are less resistant to wear than cheek teeth
What is the rate of eruption for teeth that are completely out of occlusion?
Easley Textbook, ch 25
0.5cm-2cm / year
What are the black arrows indicating in this incisor histopath image?
Ch 10
irregular but phasic growth of irregular cementum
What feature of campylorrhinis lateralis can be life threatening?
Ch 9
Nasal septum deviation
Wry nose
All features: Diagonal incisor occlusion, Focal cheek teeth overgrowths, Nasal septum deviation, Shortening of the incisive bones
The prevalence of hypodontia is estimated to be:
Ch 9
< 1%
A supernumerary tooth that is characterised by a simple, usually conical shaped crown with a single root is known as which type of supernumerary tooth?
Ch 9
Haplodont supernumerary tooth
Define a Tuberculate supernumerary tooth
Ch 9
A tooth with complexly-shaped clinical and reserve crowns with multiple raised tubercles with deep occlusal indentations on the occlusal surface.
What is a connate supernumerary tooth
ch 9
composed of two or more tooth elements joined together, possibly arising from the fusion of two or more tooth germs or alternatively from a partial splitting of an embryonic tooth into two or more parts – not necessarily supernumerary
Image from Dixon VCNA 2005 “Supernumerary teeth in the horse”
What developmental structures can remain visible around the apex of young adult cheek teeth?
Staszyk 2015 EVE “Equine dental and periodontal anatomy A tutorial review”
Dental follicle and enamel organ (before roots close) – “eruption cysts”
Eruption cysts aka Prominentiae osseae transistoriae
What do the arrows indicate anatomically of this CT of a 306?
White and Dixon 2010 EVJ
Transition from pulp to subocclusal secondary dentin
In Froydenlund’s study “Anatomical and histological study of the dorsal and ventral nasal conchal bullae in normal horses” what were the main anatomical findings noted for the VCB and DCB?
Froydenlund Vet Rec 2017
DCB was larger than the VCB, containing more septae, cellulae and drainage apertures.
No communications were identified between the bullae and the immediately adjacent paranasal sinuses.
At what age do incisors start to decrease in length?
Easley ch 27
13-15 yo
What is the range of length of infundibulum?
Pearce 2016 EVE
2mm - 89mm
What developmental pathology is noted in this maxillary cheek tooth?
Pearce 2016 EVE
A supernumerary infundibulum is present palatal to the normal rostral and caudal
infundibula
What does the term anelodont mean?
Easley 2022
limited growth period teeth
in reference to brachydont and hypsodont teeth continuing to develop roots after the end of crown formation
What is the definition of the term elodont?
Easley 2022
Teeth that continually grow and elongate their crown throughout all of an animal’s life
occurs in rodents and lagomorphs
What is morphologic description of the structure of Type 1 enamel and where is it located?
Easley 2022
Composed of prisms that are oval or rounded on cross section that lie in parallel rows between plates of dense interprismatic enamel
located at amelodentinal junction (between enamel and dentin)
What is morphologic description of the structure of Type 2 enamel and where is it located?
Easley 2022
Composed soley of enamel prisms in horseshoe to keyhole shapes oriented in all three planes with no interprismatic enamel
Located on abaxial/periphery of enamel layer
What pulp horn numbers are in the image below?
Easley 2022
A.) 6
What pulp horn numbers are shown in the image below?
Easley 2022
A.) 1
B.) 2
D.) 3
C.) 4
E.) 5
What pulp horn numbers are shown in the image below?
Easley 2022
A.) 7
B.) 8
What pulp horn numbers are shown in the image below?
Easley 2022
A.) 6
What pulp horn numbers are shown in the image below?
Easley 2022
D.) 1
E.) 2
A.) 3
B.) 4
C.) 5
What pulp horn numbers are shown in the image below?
Easley 2022
A.) 7
In this histology image of an infundibulum what do the red arrows represent?
Easley 2022
Lateral branches of the central vascular channel
What do CP, BS, AVB and BT stand for in the image below?
Easley 2022
CP: cortical plate
BS: bony spongiosa
AVB: alveolar bone
BT: bony trabeculae
What do the white arrows below represent?
Easley 2022
Sharpey’s fibers
What do Pcd, Hcd, Mcd, Mstd, Encd stand for?
Easley 2022
Pcd: Protoconid
Hdc: Hypoconid
Mcd: Metaconid
Mstd: Metastylid
Encd: Entoconid
What do Pac, Mc, Hc, Pce, Prc stand for?
Easley 2022
Pac: Paracone
Mc: Metacone
Hc: Hypocone
Pce: Protoconule
Prc: Protocone
According to Easley’s 2022 textbook, at what years of age do dental stars on the mandibular incisors traditionally appear?
Chp 7
01s 5 years
02s 6 years
03s 7 years
stars are the red arrows, red asterisk infundibulum/cups
What is the colloquial term for the structure demarcated by the red arrow and when does it change from oval to round and dissappear in most breeds?
Easley 2022, Chp 7
Enamel spot
oval to round between 5-12 years of age
Disappears between 12-18 years
