Jad_Local factors

Question 1

Who proved that the primary etiology of periodontitis is dysbiotic biofilm and excessive immune response in a susceptible host?

Answer 1

Hajishengallis ‘15

Question 2

What is the prevalence of the palatoradicular groove?

Answer 2

Kogon ‘86: ** 4.6%**

Goon classification:
Mild: ends at or just after CEJ
Moderate: extends to some dist. along the root
Complex: extends along entire root length

Question 3

How common are CEP’s in the Egyptian and the Asian populations? Describe the % of CEP’s for each molar type.

Answer 3

**Bissada & Abdelmalek ‘73: **
Overall: 8.6%
* 2nd mandibular molar: 15%
* 2nd maxillary molar: 9%
* 1st mandibular molar: 8%
* 1st maxillary molar: 3%
Hou & Tsai ‘87:
* 1st mandibular molar: 74%
* 1st maxillary molar: 62%
* 2nd mandibular and maxillary molars: ~50%

Question 4

Describe how to classify CEP’s

Answer 4

Master & Hoskins ‘64:
Grade 0 : none
Grade 1: slight projection of enamel
Grade 2: approaching furcation, but not inside
Grade 3: goes inside the furcation

Question 5

What 2 landmark studies proved that calculus is not the primary etiology of periodontal disease?

Answer 5

Listgarten & Ellegaard ‘73: (Listerine) Calculus sterilized by chlorhexidine allows normal attachment. (Histologic monkey study; Has not been replicated since)
Allen & Kerr ‘65: Injected sterile vs. nonsterile calculus into guinea pigs. The sterile calculus had only a mild foreign body reaction, whereas the nonsterile one had significant inflammation and infection

Question 6

What is the prevalence of Enamel pearls?

Answer 6

Moskow & Canut ‘90: 2.6%

Question 7

Describe the depth and percentages of root concavities in molars and premolars.

Answer 7

These studies only looked at 1st molars and premolars.
Bower ‘79b:
Maxillary 1st molar: (% prevalence / mm depth)
MBu: (94% / 0.3)
DBu: (31% / 0.1)
P: (17% / 0.1)
Mandibular 1st molar: (% prevalence / mm depth)
M: (100% / 0.7)
D: (99% / 0.5)
Booker & Loughlin ‘85:
Maxillary 1st premolar mesial side:
Single rooted: (100% / 0.35 mm)
Double rooted: (100% / 0.44 mm)

Question 8

What are the average openings of the furcation entrances and why is this important?

Answer 8

Bower ‘79:
81% of furcations is ≤1mm wide
58% is ≤ 0.75 mm wide
This means curettes can’t easily access furcations

Question 9

What are the prevalences of bifurcation ridges in 1st mandibular molars? HOW LOW YOUR OXYGEN CAN GO BEFORE YOU FAINT ON THE MOUNTAIN

Answer 9

The study only looked at 1st mandibular moalrs
Everett ‘58: 73% prevalence

Question 10

How do you classify root trunk lengths?

Answer 10

Ochsenbein ‘86:
Short: Type A
Medium: Type B
Long: Type C
Maxillary molar: 3 / 4 / 5mm is Type A / B/ C
Mandibular molar: 2 / 3 / 4 mm is Type A / B / C
Maxillary molars typically have longer root trunks than Mandibular ones.

Question 11

What are the average furcation depths in maxillary molars? hint: YOU ARE SICK OF MEMORIZING the 3 furcations!

Answer 11

Dunlap & Gher ‘85:
Maxillary molars (Mesial / buccal / distal): 3.6, 4.2, 4.8 mm
(Start with 3.6 and add 0.6 each time)

Question 12

What are the average furcation depths in mandibular molars? WHAT GPA DO YOU WANT TO GET INTO PERIO!

Answer 12

Mandelaris ‘98:
Mandibular molars (Lingual / buccal): 4.1, 3.1
Buccal is shallower than the lingual for the mandibular molars.

Question 13

What are the average furcation depths for maxllary 1st premolars?

Answer 13

King of Fracture
Booker & Loughlin ‘85: (mesial): 7.9 mm
Joseph ‘96: (mesial / distal): 7.9 mm, 7.6 mm

Question 14

How common are accessory canals in molars? What about for all teeth in general? HE ATE TOO MUCH!

Answer 14

Gutmann ‘78: looked at extracted molars
28.4% - average prevalence of accessory canals in all molars
29.4% - mandibular molars
27.4% - maxillary molars

De Deus ‘75: For all extracted teeth : 27.4% prevalence of accessory canals.

Question 15

What are the predisposing factors for cemental tears? What are the signs?

Answer 15

Lin ‘11:
* Type of tooth (more common in incisors)
* Older men > 60 years of age

Signs of cemental tears: Radiographic appearance, abscess formation, deep PD >6mm, presence of heavy attrition. Tooth is usually vital.

Question 16

Do open contacts cause gum disease? How are open contacts classified?

Answer 16

**A plunger cusp and food impaction **need to be present in an open contact to cause periodontal disease.
Hancock ‘80 Open contacts themselves do not cause gum disease. However, food impaction is associated with deep PD.
Classification of open contacts:
1. Tight: Floss definitely is resisted
2. Loose: Floss is minimally resisted
3. Open: Floss has no resistance
Jernberg ‘83: Open contacts had less debris and about 0.5 mm more CAL loss.

Question 17

Does tooth mal-alignment cause periodontal disease? ARMY PEOPLE ON AN ISLAND OF CANADIAN WEST COAST

Answer 17

Ainamo ‘72: Army recruits. More tooth misalignment = higher GI, PI, CAL loss.
Ingervall ‘77 Dental student study. No significant correlation between malalignment and periodontal disease. (However, these were dental students and probably had good hygiene)

Question 18

What studies looked at root proximity and periodontal disease?

Answer 18

Tal ‘84: 2.6 mm - distance greater than this led to intrabony defect formation (up to 57%). However, less than 2.6 mm between teeth led to a lesser freq of IBD (up to 20%)
Vermylen ‘05: Root proximity increases the risk of periodontal disease.
* At least 1 space with proximity: OR 2.1
* At least 2 spaces with proximity: OR 3.6
* 5+ spaces with proximity: OR 6.5
Severity levels according to Vermylen:
- Sev. 1: 0.5-0.8 –> Cancellous bone present
- Sev. 2: 0.3-0.5 –> Fused LD
- Sev. 3: < 0.3 –> only PDL

Question 19

What 3 studies classified the root proximity?

Answer 19

Heins & Wieder ‘86
>0.5 mm : cancellous bone present
0.3 - 0.5 mm: only lamina dura present
<0.3 mm: only PDL present
Vermylen ‘05
Same as above, but used >0.8 instead of >0.5 probably just to publish it
Ercoli & Caton ‘18
Same as Vermylen

Question 20

Describe the Kugelberg retrospective study on 3rd molars and how age affects the post-extraction PD.

Answer 20

Kugelberg ‘90
The % of sites with PD >7mm was related to the age.
≤25 years old: 25% had PD >7mm
>25 years old: 52% had PD >7mm
Older age basically doubles the risk of having deep PD after 3rd molar extraction.

Question 21

Why do we graft the intrabony defects distal to 2nd molars (7 mm PD) after the 3rd molar removal? Name the study.

Answer 21

Sammartino ‘09: 6 year study that proved that GTR with BioOss (with or without membrane) significantly improved the PD and CAL gain, and prevented future periodontal disease in the site.
6 year residual PD:
No GTR: 6.4
BioOss only: 3.88
BioOss + membrane: 3.15

Question 22

Does retention of hopeless teeth affect the adjacent teeth? Describe the studies

Answer 22

It is ok as long as the patient does regular maintenance.
Machtei ‘89: Negative effect without maintenance.
Machtei & Hirsch ‘07: Neutral effect with maintenance.
DeVore ‘88: Neutral effect with maintenance.

Question 23

Do subgingival margins cause periodontal disease?

Answer 23

Stetler & Bissada ‘87: Yes, subgingival crowns had higher GI, PI, inflammation
Newcomb ‘74: Yes, the closer the crown margin was to the deepest part of the sulcus, the greater the gingival inflammation (Strong -ve correlation betw ging. inflammation and dist. from margin to crevice base)

Question 24

How do overhanging restorations affect the gum disease?

Answer 24

Jeffcoat & Howell ‘80: Medium and large overhangs caused more alveolar bone loss (compared to small and no overhangs)