mechanical plaque control Flashcards
what is the critical mass theory
says that we want to use mechnical plaque therapy to physically disrupt and hence eliminate plaque biofilm in order to reduce the quantity of bacterial plaque to a critical level that results in an equilibrium between residual microbes and host response
what are the overarching goals of scrd
1) disrupt and alter plaque
2) remove toxic substances responsible for tissue damage
3) achieve biologically acceptable root surfaces
4) achieve reduction in PD and CA gain
why do we want to remove toxic substances
because periopathogens produce virulence factors that are responsible for tissue breakdown and removal of these endotoxins result in biologically acceptable root surfaces compatible for fibroblast attachment
what change in microflora are we aiming for with perio therapy
Listgarten 1978
modest, transient shift in microflora from gram negative microbes associated with perio to gram positive rods and cocci associated with health
evidence for wanting a smooth root surface
Keenan et al 1980: there is a direct relationship between surface roughness and rate of supragingival bacterial colonization
Lindhe 1984: smooth root surfaces are compatible with normal healing of dentogingival complex
but also got another study Rosenberg & Ash 1974 saying that surface roughness has no effect on plaque retention and gingival inflammation
why is reduction in PD impt
- better perio stability
- facilitates OH measures
how long does it take for clinical attachment gain after scrd
4-6 weeks: short term due to JE
6-12 months: long term due to CT maturation
what are the factors affecting periodontal healing after scrp
OPERATOR FACTORS
1) tools
- Cobb 2002, Badersten 1981/84: no clinical difference between manual and ultrasonic scaler. both unable to remove all calculus and bacteria completely, and can also achieve smooth root surfaces free of calculus. just that manual takes more time
2) technique
Eberhard 2008, 2015: no difference between clinical results achieved for quadrant scaling vs FMD. regardless of technique, maintaining optimal OH is impt in achieiving perio stability in the long term. choice of modality depends on indiv case, patient preference
- special case like aggressive perio should do FMD with antibiotics, cannot be stages over multiple visits because need antibiotics
PATIENT FACTORS
1) OH
- Axelsson & Lindhe 1978, 1981 shows that with good OH and regular perio maintenance, it helps to decrease percentage of gingivitis
2) systemic factors
- if got DM then will have poorer wound healing. Nelson et al 1990: DM have 2.6x increased risk of tooth loss due to perio
3) envt factors
- smoking
- stress
TOOTH FACTORS
1) PPD
- based on Lindhe’s critical probing depths, if the PPD was <2.9mm then there will be more caloss caused with scrp. if the ppd >4.2mmm, then surgery will result in greater CA gain than scrp
- Waerhaug 1978: if ppd >5mm, complete removal of plaque and calculus is often not successful
2) position of the tooth in the arch
- Buchanan & Robertson 1987: different teeth have differing amounts of calculus left after scrp:
- premolars > molars, posterior> anterior teeth, proximal surface> facial surface
3) anatomical factors
- grooves, concavities which are hard for patient and clinician to clean
- Bower: furcation involvement is tough bc 58% of furcation entrances are too narrow for the standard curette to access
4) types of defect
- vertical defects tend to have poorer prognosis because of bony topology, where soft tissue height is held up by other end of vertical defect. so deep ppd tends to persist
5) type of microflora present
- Haffajee & Socransky 1994: Aa, Pg, Td more resistant to scrp
evidence for necessity of adequate home care
Badersten 1981, 1984 says:
- effective home plaque control able to resolve signs of inflammation
why need to scrp again at ipta
it is recognized that shifts to a sub gingival microbial flora representative of health appears to be transient. so to sustain the positive effects of perio treatment, scrp must be performed periodically during the maintenance phase of therapy (Lindhe, Nyman 1984)
do we need to achieve root surface smoothness (evidence?)
it has long been assumed that a smooth root surface is a clean surface but it has actually yet to be determined that a smooth root surface is indeed a desirable end point of non surgical perio therapy
the evidence that dont need root surface:
Khatiblou and Ghodssi (1983) reported that perio healing, reductions in PPD, and attachment gains, were independent of root surface texture
But Waerhaug (1956) notes that the intentional roughening of subg enamel in dogs resulted in an increased depostion of baterial plaque and calculus
PLUS Quirynen & Bollen 1995 noted that rough suprag surfaces accumulate and retain more bacterial plaque
PLUS Lindhe 1984 noted that smooth root surfaces were compatible with normal healing of dentogingival complex
why need to wait 4 weeks after IPT before reviewing (quote evidence)
because the greatest change in ppd reduction and gain in clinical attachment occurs within 1-3 months post scaling and root planing (Morrison et al 1980, Badersten 1981)
so Caton et al 1982 says that evaluation of response of the periodontium to scrd should be performed no earlier than 4 weeks as measurements taken prematurely will not be representative of completed healing and could be misintepretated as poor clinical response
why is home plaque control NOT enough
has limited effect on controlling periodontitis
Badersten 1981, 84: 0.5-0.8mm reduction in PD
Kho 1985 says that home plaque control has no impact on subg flora when pockets are >5mm
