Periodontal Anatomy Flashcards
What are the 3 parts of evidence based dentistry
dentist’s expertise
scientific evidence
Patient needs and preferences
What is PICO
Population to be examined
Intervention that is to be inspected
Comparison to what is currently known
Outcome to be evaluated
What are the steps for making an evidence based decision in practice
Formulate a PICO question Research the PICO question and collect evidence Analyze the data that has been collected Apply the data to the dental practice Evlauate the results
What is the ranking of scientific evidence
Systematic review/meta analysis RCT Controlled trials Cohort studies Case-control studies Cross-sectional studies Case report studies
What is the difference between sensitivity and specificity
Sensitivity is the ability of a test to correctly identify diseased individuals
Specificity is the ability of a test to correctly identify a healthy individual
Internal validity vs external validity
Internal validity is the soundness of the study, including bias and statistics
External validity is how much the study relates to the general population
Where does the vascular supply of the periodontium originate
The external carotid artery and its main branches, lingual, facial, and maxillary arteries.
Locally the blood supply comes from the supra-periosteal vessels and the vessels from the PDL and bone
What is the main innervation for the periodontium
The trigeminal nerve and its branches
What is attached gingiva
The gingiva from teh base of the sulcus to the mucogingival junction
Consists of thick lamina propria and deep rete pegs
Goaslind et al reported the gingival thickness is 1.25mm+/- 0.42mm
Where does keratinized attached gingiva extend
Gingival margin to the mucogingival junction
What is alveolar mucosa
non-keratinized covering of the alveolar bone, from the mucogingival jumction apical
What is Ante’s law?
The root surface area of the abutment teeth must be equal or greater than that of teeth being replaced with pontics, which determines the number of teeth required for a bridge.
What are the characteristics of healthy gingiva?
Coral pink, firm, follows the CEJ of the teeth, may be stippled or pigmented.
What are the 5 types of gingival fibers
Dentogingival group Alveologingival group Dentoperiosteal fibers Circular group Transseptal group
What is the composition of the oral mucosa
masticatory mucosa (gingiva/hard palate) Lining mucosa (alveolar mucosa, floor of mouth) Specialized (dorsum of tongue)
Oral (masticatory) epithelium characteristics
Orthokeratinized stratified squamous
surface cells lose nuclei and contain keratin
Extends to the sulcular epithelium
Oral sulcular epithelium characteristics
Epithelium that lines the sulcus
No rete pets in healthy tissue
nonkeratinized
Junctional epithelium characteristics
Attaches to the tooth via hemidesmosomal layer and basal lamina
nonkeratinized
permeable
most apical part lies at the CEJ in healthy tissue
What are the 4 layers of the masticatory epithelium
Stratum Basale (cuboidal cells at the basement membrane) Stratum Spinosum (spines contain Langerhans cells for immune surveillance) Stratum granulosum (cells appear flat, keratinocytes migrating from stratum spinosum known as granular cells) Stratum corneum (outermost layer, dead cells that are ortho and Para keratinized)
Where is the widest and narrowest zones of gingiva?
Widest in the Maxillary anterior area
Narrowest facial of Mandibular premolars
Composition of connective tissue
fibrous, mostly type 1 collagen, ground substances, mucopolysaccharides. Contains WBC, lymph, and nerves
average width greater than 1mm
What determines of epithelium is keratinized or nonkeratinized
The underlying connective tissue.
What is periosteum and what is its function
Periosteum is highly vascular connective tissue covering all boney surfaces except joints and muscle attachments
Consists of an inner cambium layer (containing osteoblasts and osteoprogenitor cells) and an outer fibrous layer
Involved in bone healing and bone regeneration. Also a channel for blood supply and nutrients for bone tissue
Where is the average width of PDL the greatest and where is it the narrowest
Greatest at the apex, and narrowest in the middle
Average widthe of PDL is 0.2mm, wider as you age
What provides blood supply to the PDL
Superior and inferior alveolar arteries.
PDL is vascular tissue
What are the functions of the PDL
protect vessels and nerves
Transmit occlusal forces
Attach the tooth to bone
Perform formative and remodeling functions
What are the fibers of the PDL
alveolar crest, horizontal, oblique, interradicular, and apical
Oblique most numberous
Describe and define Ankylosis
fusion of cementum and alveolar bone with obliteration of the PDL
Occurs after chronic periapical inflammation, tooth reimplantation, and occlusal trauma
What is the composition of alveolar bone
Cortical bone
Calcellous trabeculae
Alveolar bone proper
What are cellular and acellular cementum
acellular cementum is located on the enamel at the CEJ. No cementocytes and forms slowly
Cellular cementum is located at the apical 1/3 of the root, is more irregular and forms rapidly. It’s width increases with age
How does cementum join the enamel
60% the cementum and enamel overlap
30% cementum and enamel form a butt joint
10% of the cementum and enamel are separated by a gap
What is the difference between intrinsic and extrinsic cementum
intrinsic is cementum fibers produced by cementoblasts
extrinsic is made of sharpeys fibers from the PDL
How does the junctional epithelium attach to the cementum
Via hemidesmosomes and replicates every 5 days
What is the composition of the TMJ disc
dense connective tissue
Describe the movement of the TMJ
Upper compartment has a translational movement
Lower compartment has rotational movement
What is meniscal derangement with and without reduction
with reduction - the disc as well as the posterior band of the meniscus is anteriorally placed, but moves into proper position during opening
without reduction - the meniscus remains anteriorly displaced at full opening
Describe the 4 types of collagen
Type I - skin, tendon, vascular ligature, organs, bone
Type II - Cartilage
Type III - reticular fibers, found alongside type I and in smooth muscle
Type IV - forms basis of cell basement membrane
Supracrestal tissue attachment height
Garguilo
connective tissue 1.07mm
Junctional Epithelium 0.97mm
Sulcus 0.69mm
What happens when the supracrestal attachment is violated
periodontal bone loss and inflammation may occur
The body will try to re-create the supra-crestal attachment
Gunay study found more BOP and PD interproximal when the margin was less than 1mm from the bone
What is the most common area of recurrent pockets
mesial aspect of maxillary first premolars and first molars
What is the relationship between tooth support and root morphology
Root curvatures and concavities increase periodontal support due to multi-directional fiber orientation
multirooted teeth have increased support and resistance to applied forces
divergent roots increase stability and allow for more bone support
Conical roots have less attachment area and are not as stable
Enamel pearls can weaken periodontal attachment
Root fractures can lead to periodontal destruction
Which muscles elevate and depress the mandible
elevate - temporalis, medial pterygoid, and masseter
Depress - Lateral pterygoid, digastric, and mylopyoid
