Local Factors - 10042021

Question 1

Allen 1965

Answer 1

Study in Guinea Pigs to determine the reaction of periodontal tissues to sterile and non-sterile calculus:

• Sterile calculus : encapsulated in CT without inflammation or abscess formation.
• Non-sterile calculus: irritation and abcess formation,

Question 2

Most common crystal type in supra and subging. calculus

Answer 2

SupraG: OCP (outer layer) + HA (inner layer)
SubG: Whitlockite

Question 3

Zander 1953 (Calculus attachment to root surfaces)

Answer 3

4 mechanisms:

• 2ry cuticle: Epith. attachment of on Cementum after apical migration. Easily detached.
• Microscopic irregularities: previous insertion of Sharpey’s fibers (most frequent mode)
• Areas of cementum resorption: mechanical retention.
• Microbial penetration into cementum (refuted by Canis et al. 1979)

Question 4

Accessory (lateral) Canals formation

Answer 4

Failure of HERS when there is lack of Odontoblasts differentiation and dentin formation.

Question 5

Armitage 1999 (Endo-Perio)

Answer 5

Endo pathogens could accelerate periodontal disease progression.

Question 6

Gutmann 1978

(Lateral canals prevalence in extracted molars)

Answer 6

28.4% in furcation area
Mandibular molars: 29.4%
Maxillary molars: 27.4%

Question 7

Everett 1958 (Bifurcation ridges)

Answer 7

Prevalence in 1st mandibular molars is 73%

Dentin ridge covered by cementum. They interfere with optimal debridement of mand. molars leading CAL.

Question 8

Hou & Tsai (bifurcation ridges)

Answer 8

1st mandibular molars: 73%

2nd mandibular molars: 67.9%

Question 9

Lin 2011 (Cemental Tears)

Answer 9

Root surface Fx. involving C only or C & D –> Periodontal destruction.
According to Lin 2011, they are:
** M > F ( M: 77.5 % vs. F: 22.5%)
** > 60 YO & PD > 6 mm (73%)
** More common in U & L incisors (76 %)
** TFO (moderate - severe attrition) (78%)

Question 10

Master & Hoskins 1964 (CEPs)

Answer 10

Projection of E on cervical area past CEJ level, extending to or into furcation area.
Master & Hoskins classification:
Grade 0: no CEP
Grade I: discrete extension of CEJ toward the furcation
Grade II: CEP is closer to furcation, but without contacting it
Grade III: E is projected into the furcation area

Question 11

Hou & Tsai 1987 (CEPs)

Answer 11

Grade II: < Maxilla
Grade III: < Mandible
Mandibular 1st molar: 73.9%

Question 12

Bissada & Abdelmalek 1973 (CEP)

Answer 12

8-20% in Egyptian skulls (need to confirm)

Question 13

Ainamo 1972 (Crowding)

Answer 13

Increase in GI, PI, calculus and CAL in misaligned anterior teeth in maxilla and mandible.
(Also in Alsulaiman 2018: crowding of mand ant –> increased PD)

Question 14

Enamel Pearls (EP)

Answer 14

Ectopic isolated enamel deposits in furcation areas originating from HERS cells that did not detach from dentin matrix during tooth development, and later differerntiate into ameloblasts.

Question 15

EP clinical significance?

Answer 15

Careful when removing them for for GTR –> may contain dentin and pulp.
Prevent CT attachment and allow plaque retention

Question 16

Cavanha 1965 classification (EP)

Answer 16

Radicular is the most common location
75% in Maxi (2nd and 3rd) molars –> betw. DB & P roots
followed by Mandib. molar –> buccal surface

Question 17

Moskow & Canut 1990

Answer 17

Prevalence of EP is 2.6%

Question 18

Furcation entrance?

Answer 18

Transitional area between divided and undivided part of the root. Hinders access for the patient and the clinician. especially when smaller than the average diameter of hand instruments (0.75 mm)

Question 19

Bower et al. 1979

Answer 19

Furcation entrance ≤ 0.75 mm: 
Maxillary molars:
Buccal (85%) > Distal (54%) > Mesial (49%)
Mandibular molars:
Buccal (63%), Lingual (37%)

Question 20

Bower et al. 1979

Answer 20

81% of furcations of 1st molars are < 1 mm

& 58% are < 0.75 mm

Question 21

Hunter & O’ Leary 1984 (Hand vs US instrumentation & residual calculus) (confirm?)

Answer 21

“Overall, hand-scaled root surfaces demonstrated less residual calculus (5.78%) than ultrasonically treated surfaces (6.17%). Twenty teeth treated by each method were then prepared for histologic evaluation and evaluated under the light microscope at magnification X 100 for residual calculus and relative smoothness. Residual calculus was found on four ultrasonically and 12 hand-treated teeth and was almost evenly distributed between anterior and posterior teeth for both methods”

Question 22

Mattea (OFD vs. SRP in open vs. closed furcation

Answer 22

????

Question 23

Devore 1984 (Retained hopeless teeth?)

Answer 23

Retained hopeless teeth have no effect on proximal periodontium pre- and post Perio therapy

Question 24

Machtei and Hirsch 2007 (Retained hopeless teeth?)

Answer 24

Hopeless teeth that were retained and maintained did not affect the bone level of adjacent teeth

Question 25

Kugelberg 1990 (impacted 3rd molar removal?)

Answer 25

``` Retrospective about the effect of impacted L 3rd molar removal on the perio of 2nd molar (2-4 year FU). - PD ≥ 7mm (4 years) ≤ 25 YO --> 25% of cases. ≥ 26 YO --> 51.9% of cases. - IDB > 4 mm (4 years) ≤ 25 YO --> 4.2 % of cases. ≥ 26 YO --> 44.7 % of cases. Better healing in pat. < 25 YO Benefit on the Perio health of D of 2nd molar after removal of 3rd molar. ```

Question 26

Kugelberg 1990 (impacted 3rd molar removal "Retro"?)

Answer 26

``` Retrospective about the effect of impacted L 3rd molar removal on the perio of 2nd molar (2-4 year FU). - PD ≥ 7mm (4 years) ≤ 25 YO --> 25% of cases. ≥ 26 YO --> 51.9% of cases. - IDB > 4 mm (4 years) ≤ 25 YO --> 4.2 % of cases. ≥ 26 YO --> 44.7 % of cases. Better healing in pat. < 25 YO Benefit on the Perio health of D of 2nd molar after removal of 3rd molar. ```

Question 27

Kygelberg 1991 (impacted 3rd molar removal "Pro"?)

Answer 27

``` Prospective about the effect of impacted L 3rd molar removal on the perio of 2nd molars IBD: - ≤ 20 YO Improved: 46.2% Worse: 8.6% - ≥ 30 YO Improved: 34.9 % Worse: 24.1 % ```

Question 28

Samarrtino 2009 (BPBM graft after 3rd molar ext)

Answer 28

Long term efficacy of using BPBM (Bio-oss) vs BPBM + collagen membrane on preventing 2nd M defects after ext of fully impacted 3rd M. Residual PD after 6 years: o Bio-oss: 3.88 mm o Bio-oss + mb: 3.15 mm o Control: 6.4 mm Bone graft w or w/o CM showed significant reduction in PD and CAL gain. Efficient to prevent second molar defect

Question 29

Goon 1991 classification of Palatogingival grooves

Answer 29

* Mild grooves: are gentle depressions of the coronal enamel which terminate at or immediately after crossing the CEJ * Moderate grooves: continue to extend some distance apically along the root surface in the form of a shallow or fissured defect * Complex radicular grooves: are deeply invaginated defects that involve the entire length of the root or that separate an accessory root from the main root trunk

Question 30

Kogon 1986 (Palatoradicular grooves)

Answer 30

Prevalence was 4.6% for C and L incisors combined. | 58% extend > 5 mm from CEJ

Question 31

Bower 1979 (root concavities)

Answer 31

Prevalence: Maxi 1st Molar: MB (94%) - DB (31%) - P (17%) Mand 1st Molar: M (100%) - D (99%) Depth: Maxi 1st Molar: MB (0.3) - DB (0.1) - P (0.1) Mand 1st Molar: M (0.5) - D (0.7)

Question 32

Booker and Loughlin 1985 (1st Premolar)

Answer 32

``` Root concavity prevalence and depth: Mesial (100%) Single rooted: 0.35 mm at CEJ 2 rooted: 0.44 mm at CEJ Distal (39.3%) ```

Question 33

Waerhaug 1979 (Plaque free zone)

Answer 33

Distance from Apical extent of plaque and ABC is 1.63 mm (0.5-2.7 mm)

Question 34

Vermylen 2005a (Severity of Root proximity)

Answer 34

1: 0.5 - 0.8: small amount of cancellous bone between adjacent roots. 2: 0.3 - 0.5: only cortical bone and CT attachment between adjacent roots. 3: < 0.3: only CT attachment betw adjacent roots.

Question 35

Tal 1984 (IP distance & IB pockets

Answer 35

2.6 mm IP distance is a critical distance. > 2.6 mm: 20-57% IBP < 2.6 mm: 5-20% IBP IPD of 2.1 - 4.5 mm +ve correlated with IBP Largest IPD: Maxi : 1st PM Mand: Canine

Question 36

Vermylen 2005b (root proximity as a risk for PD)

Answer 36

Periodontal patients had 5 times more root proximity than control in mand incisors. RR for Periodontal disease: - 1 interdental space with root proximity: 2.1 - 2 interdental spaces 3.6

Question 37

Heins and Wieder 1986 (Histological nature and incidence of interproximal width)

Answer 37

>0.5 mm – cancellous bone <0.5mm – no cancellous, only lamina dura <0.3 mm – Only PDL space

Question 38

Hou and Tsai 1997 (root trunk)

Answer 38

Root trunk extends from the CEJ to the furcation. A: RT extends to 1/3 of total length of the root (Coronal third) B: RT extends up to ½ of the root length C:RT extends to the apical 1/3 of the root length.

Question 39

Ochsenbein 1986 (root trunk classification)

Answer 39

Classified root trunk as short (A), medium (B) or long (C) For maxillary molars ≥ 3- 4- 5 ≤ For mandibular molars ≥ 2- 3- 4 ≤

Question 40

knowing the length of the root trunk determines the prognosis of the tooth when there is furcation involvement.

Answer 40

Prognosis is different for furcation involvement on a RT type A vs when we have furcation involvement on a type C. (A is better than C). Tunneling can be done on Type A RT with furcation involvement as long as the furca is wide

Question 41

Mendelaris 1998, Dunlap Gher 1985, Joseph 1996 (Root trunk length)

Answer 41

``` Root trunk length: Max. 1st molars: M: 3.6 B: 4.2 D: 4.8 Mand. 1st molar: B: 4.1 L: 3.1 Max. 1st PM: M: 7.9 D: 7.6 ```

Question 42

Mathew 2004, Arx 2017 (Vertical root fracture manifestations)

Answer 42

• Enlargement of the PDL along the entire length of the root • Isolated and very narrow periodontal pocket • Recurrent abscesses ONLY TTT IS EXTRACTION

Question 43

Newcomb 1974 (subG crown margin)

Answer 43

Examined the gingival inflammation degree that is associated to sub-g crown margin located at different levels of the gingival crevice Group 1: CM-BC 0.35mm Group 2: CM-BC 0.5mm Group 3: CM-BC 0.75mm Group 4: CM-BC 1 mm Very strong negative correlation between gingival inflammation and the distance of the crown margin from the base of the crevice The closer the CM to the GC the more severe the inflammation

Question 44

Schatzle et al 2001 (Root proximity and periodontal disease)

Answer 44

Periodontal patients had 5 times more root proximity than control in mand incisors. RR for Periodontal disease: - 1 interdental space with root proximity: 2.1 - 2 interdental spaces 3.6

Question 45

Heins and Wieder 1986 (Histological nature and incidence of interproximal width in human population sample) premolars and molars

Answer 45

>0.5 mm – cancellous bone <0.5mm – no cancellous, only lamina dura <0.3 mm – Only PDL space

Question 46

Hancock in 1980 (open contact classification)

Answer 46

Tight: definite resistance to the passage of floss Loose: minimal resistance Open: no resistance

Question 47

Koral, Howell, and Jeffcoat 1981 (Open contact)

Answer 47

Open interproximal contacts were not associated with increased alveolar bone destruction in Class, I, III and IV periodontal disease groups. In group of 53 Class II cases, open contacts were found to be associated with an average of 2.4% less relative bone height than contralateral closed contacts

Question 48

Jeffcoat and Howell 1980

Answer 48

Size of overhang depending on the interproximal space that is occupying: Small – <20% Medium –20-50% Large -- >51% M and L overhanging was associated with more bone loss, S was NSSD

Question 49

Leif Jensson 1994

Answer 49

Periodontal pockets at proximal sites with marginal overhangs were significantly deeper (0.42 mm) compared to sites with metal restorations without overhangs. The influence of a marginal overhang on pocket depth and radiographic attachment decreases with increasing loss of periodontal attachment in periodontitis-prone patients (NSSD when radiographic attachment loss >6mm). The effect on pocket depth of a marginal overhang may act synergistically, potentiating the effect of poor oral hygiene

Question 50

Jeffcoat and Lang 1983

Answer 50

More G-ve bacteria with overhangs