chpt 5: local factors Flashcards
definition of biofilm
A multispecies community of microorganisms that adhere to each other and a surface and are encased in an extracellular matrix. The extracellular matrix is a complex polymeric substance that protects the microorganisms from environmental stresses. Bacteria living in a biofilm have a different physiology from free-living bacteria and are more difficult to eradicate with antibiotics. Dental plaque is the prototypical example of a biofilm.
define Calculus
A hard concretion that forms on teeth or dental prostheses through calcification of microbial plaque.
define cemental tears
A specific type of root surface fracture and characterized by the detachment of a cemental fragment.
define cementicles
Calcified spherical bodies (0.2 to 0.3 mm) composed of cementum lying free within the periodontal ligament, attached to the cementum, or embedded within it
how does bacteria attach to the tooth
in the biofilm, through van der Waals forces, glycocalyx, and glycoprotein receptors within a salivary pellicle and negative surface charges mediated by teichoic acid of gram-positive bacteria
composition of supra versus sub gingival calculus
supra: high conc of carbonate and Mn
sub: high conc of Ca, Mg, and F; irregular distribution of F
mineral content of supra vesus sub gingival calculus
supra: 37%
sub: 58%
source of minerals for supra and sub
supra: saliva
sub: GCF
crystal type in supra and sub
supra: octacalcium phosphate and hydroxyapetite
sub: whitlockite
formation of supra versus sub
supra: heterogenous nucleation and crystal growth; variable calcification
sub: heterogenous nucleation and crystal growth; homogenous calcification
microorganisms in supra versus sub
supra: more filamentous, faster growing
sub: less filamentous, slower growing
morphology of supra versus sub
supra: heterogenous with small needle-shaped; large-ribbon-like; and bundle/rosettes crystals
sub: several crystal types like spiny, crusty, nodular, ledge/ring, individual islands, smooth veneers, and finger/fern-like
pathogenic potential of supra versus sub
supra: little evidence
sub: associated with perio disease
modes of calculus attachment according to zander 1953
1) secondary cuticle
2) direct attachment into irregularities of cementum * 20%
3) penetration into cementum *10%
4) mechanical retention in areas of resorption
what is the favored site for calculus formation?
CEJ
define enamel pearl
A focal mass of enamel that has formed apical to the CEJ and is typically located in the areas between the roots of molars
Define enamel projection
An apical extension of enamel, usually toward a furcation.
May prevent true attachment of periodontal ligament fibers upon the root surface
modes of attachment according to canis
Canis et al rejected the possibility that microorganisms can penetrate the cementum surface and considered this phenomenon as an artifact due to superimposition of a detached cementum onto the tooth structure during sample preparation. These findings were confirmed using light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM).
grade I CEP (Masters and Hoskins)
A distinct change in CEJ attitude with enamel project- ing toward the bifurcation.
grade II CEP (Masters and Hoskins)
Enamel projection approaching the furcation but not actually making contact with it.
grade III CEP (Masters and Hoskins)
Enamel projection extending into the furcation proper.
prevalence of CEP in mandibular molars
28.6%
prevalence of CEP in max molars
17%
how many isolated furcation involvements are associated with CEPs? (Masters and Hoskin)
90% (mainly buccal)
how many isolated furcation involvements are associated with CEPs? (Hou and Tsai)
prevalence of 63.2% furcation defects with CEPs and IBRs
IBRs affect primarily which tooth
mandibular molars
prevalence of CEP according to Swan and Hurt (overall and by max and mand)
32.6% overall
mand M: 33.7%
max M: 31.4%
which teeth are affected by CEPs according to Swan and Hurt
-mand 2nd M
-max 2nd M
-max 3rd M
-mand 1st M
-mand 3rd M
-max 1st M
Palatal groove
A developmental, anomalous groove usually found on the palatal aspect of maxillary central and lateral incisors
Plunger cusp
an active passage of food into the embrasure area during function
Plaque
An organized mass, consisting mainly of microorganisms embedded in a matrix of glycopolymers, that adheres to teeth, prostheses, and oral surfaces and is found in the gingival crevice and periodontal pockets. Other components include an organic, polysaccharide-protein matrix consisting of bacterial by-products such as enzymes, food debris, desquamated cells, and inorganic components such as calcium and phosphate.
mean diameter of enamel pearl
0.96 mm
prevalence of enamel pearl
4.6%
location of enamel pearl
coronal third of the root with a mean distance of 2.8 mm from the CEJ.
Moskow and Canut: incidence rate of enamel pearl
-1.1% to 9.7% (mean: 2.69%)
predilection for enamel pearl (Moskow and Canut)
maxillary third and second molars
location of furcation entrance from CEJ (Gher and Dunlap) for max 1st M
M: 3.6
B: 4.2
D: 4.8
location of furcation entrance from CEJ (Dunlap and Gher) for mand 1st M
4 for B and L
location of furcation entrance from CEJ (Gher and Vernino) for max 1st premolar
6
which root of max M has the highest root surface area (Hermann)
MB (25%) and P (24%)
which root of mand M has the highest root surface area (Gher and Dunlap)
M (37%)
D(32.4%)
prevalence of IBR in mand 1stM
(Everett) 73%
what are highly associated with IBRs (Hou and Tsai)
CEPs (63%) and class 3 furcations (25%)
prevalence of palatoradicular grooves
Everett and Kramer: 1.9%
Gher and Vernino: 3%
Withers: 2.33% (4.4% in laterals)
Kogon: 4.6%
Hou and Tsai: 18.06% (Taiwanese)
which teeth are affected by palatoradicular grooves
maxillary lateral incisors and central incisors with a possible predilection for individuals of Asian descent
what is the effect of palatoradicular grooves on the periodontal health
-higher GI, PI, PD (mean: 8.8 mm)
Cementicles
calcified spherical bodies (0.2 to 0.3 mm) composed of cementum lying free within the periodontal ligament, attached to the cementum, or embedded within it
According to Holton et al, cementicles are often observed in which teeth? prevalence?
canines and molars with an overall prevalence of 34%
cementicles in periodontal condition
The presence of cementicles has not been correlated with the pathogenesis of periodontal disease; however, root surfaces with cementicles might hinder mechanical instrumentation.
Cemental tears
specific type of root surface fracture and characterized by the detachment of a cemental fragment
cemental tear and perio (Moskow)
-located mostly at the coronal
third of the cementum, serving as susceptible sites for
calculus formation
-could be the result of inadvertent root gouging during mechanical instrumentation and can be associated with traumatic occlusion or traumatic events
how to clinically detect cemental tear
-very localized deep pocketing and radiographically (about 50% of the cases) with a localized radiolucency surrounding a “prickle-like body”
-abscess
-pockets greater than 6 mm
-a positive vitality test, healthy opposing teeth, and moderate to severe attrition.
how do dental materials affect periodontal health (Chan and Weber)
-aluminum-oxide base had minor plaque retention (32%), whereas PFM crowns (90%), natural teeth (110%), cast gold restorations (148%), and acrylic resin veneer crowns (152%) had substantially more plaque retention.
-van Dijken and Sjöström: no difference in plaque and GI with glass ionomer cement and composite versus enamel for Class V subgingival
-Proceedings from the 2017 World Workshop on the classification of Periodontal and Peri-implant Diseases and Conditions concluded that dental materials act similar to enamel as plaque retentive factors to initiate gingivitis
effect of subgingival margins on periodontal health with respect to the Schatzle and Lang studies.
-Schatzle 2001: A 26-year longitudinal study; subgingival margins exert a detrimental effect to gingival and periodontal health; loss of attachment clinically detectable 1-3 years after subgingival resto but then a “burn-out” effect occurs.
-Lang 1983: restorations with overhanging margins resulted in changes in subgingival microflora - increased proportions of gram
neg anaerobic bacteria, black-pigmented Bacteroides, and an increase in anaerobe:facultative ratio were noted. These changes may potentially initiate periodontal disease associated with iatrogenic factors.
effect of overhang margins on perio health, WRT Jeffcoat and Howell; Pack
- Jeffcoat and Howell: amalgam overhangs on the alveolar bone height. only medium and large (so over 20% interprox space occupied) overhanging restos had sig bone loss when compared with control teeth
-Pack: most overhangs were associated with PD >3mm (64.3%) and BOP (32%).
-Lang: overhangs produce more gingival inflammation and shift the microbiome more towards gram -’ve + anaerobic + elevated levels of black pigmented bacteriodes.
does removing overhangs help in periodontal health
Removal of overhangs+plaque elimination results in significant reduction of GI and it is recommended during the initial phase of periodontal therapy
Rodriguez-Ferrer 1980: greatest change in the first 4 weeks
