critical probing depths in periodontal therapy...effect of periodontal therapy 325 amination...

Journal of Clinical Periodontology 1982: 9: 323-336

Key wards: Periodontal surgery - periodonlal treatment - piaque control - regression analysis - seating andpianing.

Accqjicd for publicatioti September 10, 1981

"Critical probing depths" inperiodontal therapy

J. LINDHE, S. S. SOCEANSKY*, S. NYMAN. A. HAFFAJEE* AND E. WESTFELT

Department of Periodontology, Faculty of Odontoiogy, University of Gothenburg, Gothenburg, Sweden and•Forsyth Dental Center, Boston, MA, USA

Abstract. The present investigation was carried out on 15 individuals who were referred for treatment ofmoderately advanced periodontal disease. All patients were first subjected to a Baseline examinationcomprising assessment of oral hygiene and gingival conditions, probing depths and attachment levels.Foiiowing case presentation and instructions in oral hygiene measures, the patients were givenperiodontal treatment utilizing a split mouth design. In one side of the jaw scaling and root planing wereperformed in conjunction with a modified Widman flap procedure while in the contralateral jawquadrants the treatment was restricted to scaling and root planing only. The period from initialtreatment to 6 months after treatment was considered to be the healing phase and from 6-24 months aftertreatment the mainienance phase. During the healing phase the patients were recalled for professionaltooth cleaning once every 2 weeks. During the maintenance phase the interval between the recallappointments was extended to 3 months. Reexaminations were carried out 6,12 and 24 months after thecompletion of active treatment.

The results revealed that treatment resulted in loss of clinical attachment in sites with initially shallowpockets, while sites with initially deep pockets gained clinical attachment. With the use of regressionanalysis "critical probing depths" were calculated for the two methods of treatment used. It was foundthat the critical probing depth value for scaling and root planing was significantly smaller than thecorresponding value for scaling and root pianing used in combination with modified Widman flapsurgery (2.9 vs 4.2 mm). In addition, the surgical modality of therapy resulted in more attachment lossthan the non-surgical approach when used in sites with initially shallow pockets. On the other hand, insites with initial probing depths above the critical probing depth value more gain of clinical attachmentoccurred following Widman flap surgery than following scaling and root planing.

The data obtained from the reexaminations 12 and 24 months after active treatment demonstratedthat the probing depths and the attachment levels obtained following active therapy and heaiing weremaintained more or less unchanged during a maintenance care period which involved carefulprophylaxis once every 3 months. However, the data also disclosed that the level of oral hygienemaintained by the patients during healing and maintenance was more critical for the resulting probingdepths and attachment levels than the mode of initial therapy used. Thus, sites which during themaintenance period were found to be free from supragingival plaque were associated with shallowpockets and maintained attachment levels. In contrast, sites which harboured plaque exhibitedincreasing probing depths and further attachment loss.

The effect of treatment of periodontal disease Badersten et al. (1981), PihlstTom et ai. (1981).•las been described in !ong-term studies by e.g. Frequently the results have been reported inKnowles (1973), Ramfjord et al. (1973, 1975, terms of alteratiotis from the pretreatment1980), Lindhe & Nyman (1975), Nyman et al. status regarding e.g. oral hygiene, gingival1975, 1977), Rosling etal. (1976a, b), Knowles inflammation, probing depths, attachment

-t al. (1979, 1980), Nyman & Lindhe (1979), levels and alveolar hone height. The parameters

0303-6979/82/040323-14 $02.50/0 « 1982 Munksgaard, Copenhagen

324 LINDHE, SOCRANSKY, NYMAN, HAFFAJEE AND WESTFELT

studied have been expressed as mean valuesrepresenting the individual, different groups ofteeth or tooth surfaces. The findings reportedunequivocally demonstrate that different mod-alities of periodontai therapy may be success-ful in patients who following active therapy areincorporated in a carefully designed mainte-nance care program.

Recently Morrison et al. (1980), Badersten etal. (1981), Pihlstrom et al. (1981) and Lindhe etal. (1982) observed that reduction in probingdepths and gain of clinical attachment can beobtained by oral hygiene instruction and scalingand root planing. It was suggested (Morrison etal. 1980, Lindhe et al. 1982) that the improve-ments of periodontai health previously attri-buted to surgical methods of therapy could beobtained by non-surgical methods. This meansthat the effect of a surgical procedure per se canbe evaluated only in trials in which a controlgroup subjected to scaling and root planingalone has been incorporated.

The effect of periodontai therapy on clinicalattachment levels has been examined andrelated to initial probing depths (e.g. Knowles etal. 1979, Pihlstrom et al. 1981, Lindhe et al.1982). It was demonstrated that loss of attach-ment occurred/oHowing periodontai treatmentat sites with initially shallow probing depthswhile sites with deep pockets gained consider-able amounts of clinical attachment. Further-more, Lindhe et al. (1982) showed that thedegree of loss of attachment in initially shallowpockets and gain in deeper pockets was morepronounced following a surgical than a non-surgical mode of therapy. The findings implythat a critical initial probing depth for gain/lossof clinical attachment may exist and that thiscritical probing depth may vary not only fromone group of teeth to another but also with thetype of therapy employed. The first aim of thepresent study was to calculate the critical prob-ing depth values for one surgical and one non-surgical method of periodontai therapy.

Walker & Ash (1976) reported that micro-scopic amounts of calculus can be observed on a

root surface even after extensive instrumenta-tion. Waerhaug (1978) examined extractedteeth previously exposed to subgingival scalingand root planing and suggested that it wasdifficult or impossible to eliminate properly thesubgingival plaque in pockets deeper than 4-5mm. Similar fmdings have been reported byRabbani et al. (1981) and Tabita etal. (1981). Incontrast. Listgarten et al. (1978) in a com-parative clinical, microbiological and histo-pathological study found that subgingival scal-ing and root planing in periodontai sites withprobing depths > 5 mm was an effective meansof reducing gingival inflammation and probingdepths. This controversy led to the second aimof the present study which was to monitor,during an 18-month period of maintenancecare, sites which following active therapy wereassociated with probing depths of > 4 mm withrespect to gingival inflammation and attach-ment level alterations.

Recently it was suggested (Ramfjord et al.1981) that the degree of plaque control main-tained by the patient after active therapy was ofless importance than a professionally per-formed prophylaxis once every 3 months for themaintenance of shallow pockets and attach-ment levels. A third aim of the present study wasto evaluate the effect of the oral hygiene statuson probing depths and attachment levels duringthe maintenance care period in patients whofollowing active therapy were recalled for pro-phylaxis every 3 months.

Material and Methods

The present investigation was carried out on 15subjects, 32-57 years of age, who were referrecfor treatment of moderately advanced perio-dontai disease to the Department of Periodont-ology, University of Gothenburg. The patientiwere first subjected to a Baseline examinatiot,which included assessment oi oral hygiene status(Plaque Index; Silness & Loe 1964), gingivalconditions (Gingival Index; Loe & Silness 1963).probing depths and attachment levels. The ex-

EFFECT OF PERIODONTAL THERAPY 325

amination included all teeth present. (For de-tails regarding the examination procedure seeLindhe et al, (1982)), Following the Baselineexamirtation all patients were given a descrip-tion of their periodontal problems and detailedinstructions in oral hygiene measures. Subse-quently they were subjected to periodontaltreatment utilizing a split mouth design. In theright or left side of the jaw (by random selec-tion) debridement was performed in conjunc-tion with a modified Widman flap procedure(Ramfjord & Nissle l<ilA-MWF-group)wh\\t inthe contralateral jaw quadrants the treatmentwas restricted to scaling and root planing (7?Pt-group).

The period from initial treatment to 6 monthswas considered to be the healing phase and from6-24 months the maintenance phase. Duringthe healing phase the patients were recalled forprofessional tooth cleaning (Axelsson & Lindhe1974) once every 2 weeks. During the mainte-nance phase the interval between the recallappointments was 3 months. All patients werereexamined regarding orai hygiene, gingivalconditions, probing depths and attachmentlevels 6, 12 and 24 months after the completionof active treatment. All recordings were con-fined to the same surfaces and location pointswhich had been examined at the Baseline exami-nation. For details regarding the examinationsand treatment procedures the reader is referredto the publication by Lindhe et al, (1982),

Statistical analysisThe mean, standard deviation and 95% confi-dence intervals as well as the determination ofsignificance of difference of means using the t-test were performed according to standardmethods. Regression analysis was carried outLosing initial probing depth as the independent! X-axis) variable. The slope and X intercept"atues as well as the 95 % confidence intervalswere computed. The X intercept was considered:o be the critical probing depth (CPD). Thesignificance of differences of slope and X inter-cepts was calculated.

Results

Attachment level alterations during the phase ofhealingFig, 1 shows the regression lines for initialprobing depths and attachment level alterationsas well as the critical probing depth (CPD) forall sites treated with scaling and root planingonly (RPL), and sites subjected to Widman flapsurgery (MWF) as well. The CPD for sitessubjected to scaling and root planing was 2.9mm+0,4 while the corresponding figure fortheMWF group was 4,2 mm±0,2. This differencebetween the two modalities of therapy is statis-tically significant (P<0.01), The CPD-value of2.9 for sites treated with scaling and rootplaning only implies that sites with an initialprobing depth of less than 2,9 mm are likely toshow attachment loss as a consequence of rootinstrumentation even in patients maintained atan optimal piaque control level. On the otherhand, the same treatment of sites with initialprobing depths >2,9 mm are likely to showgain of clinical attachment. The same argumentis applicable to a treatment procedure whichinvolves root debridement in conjunction withWidman flap surgery, with the difference thatthe CPD-value for this treatment modality issignificantly higher. Consequently sites withinitial probing depths of up to a value of 4,2 mmare likely to suffer attachment ioss.

The slopes (Table 1, Fig, 1) of the tworegression lines (RPL = 0,2±0,04; MWF=0,42+ 0,04) indicate that in sites with initially deeperpockets (>7 mm) the resulting attachment gainfollowing therapy was more pronounced fol-lowing surgical than non-surgical treatment.Sites with initially shallow pockets ( < 3 mm)consequently suffered more attachment iossfollowing surgery than after non-surgicaltherapy.

Fig, 2 and Table 1 describe correspondingregression lines and CPD-values for the twomodes of treatment {RPL and MWF) of differ-ent groups of teeth (incisors, premoiars andmolars) and Fig, 3 and Table 1 of different tooth


TTACHM

m

KT

LptVEL

• 5

4

• 3

2

1

1 -

- - 2

- 3

- 4

- 5

m)ALL TEETH AND SURFACES

ALTERATIOf^S: BASELWE-REEXAMlNATION 6 MONTHS

RPL'SCALINQ AND ROOTPLANINGMWF* MODIFIED WIDMAN FLAP

ttJ-7S8^ ^

^^.^^'"'^'^ N-790^ • "

5 6 7 8 9 10INITIAL PROBING

DEPTH mm

MWF4.2 ± 0.2

RPL2.9 I 0.3

LOSS (mm)

surfaces (buccal, interproximal, lingual). It isobvious that for each category of teeth andtooth surfaces the non-surgical mode of therapyyielded lower CPD-values than a treatmentprocedure that also included the use of modifiedWidman flaps. The values describing the slopeof the regression lines (Table 1) were con-sistently higher for sites in the MWF-groupthan in the RPL-group.

Fig. I. Diagram illustrating alterationsof the attachment level (gain and loss)between the Baseline examination andthe reexamination after 6 months. Theinitial probing depth values are de-scribed on the X-axis. The regressionlines illustrating the effect of scalingand root planing (RPL) and perio-dontai surgery (MWF) intersect theX-axis at points representing initialprobing depths (PD) of 2.9±0.3(RPL) and 4.2 ±0.2 (MWF).Das Diagramm zeigt die Veranderun-geti des Attaehmentniveaus (Gewinnund Verlust) zwischen der Ausgangs-uniersuchung und der Nachuntersuch-ung nach 6 Monaten. Die urspriing-lichen Sondierungstiefen sind auf derAbzisse (X-Achse) abgesetzt. Die Re-gressionslinien. die den klinisehen Ef-fekt der Zahnsteinentfernung und Wur-zelglattung (RPL) und der Parodontal-chirurgie (MWF) zeigen. kreuzen die X-A chse an den Punk ten. die die ur sprung-lichen Sondierungstiefen von 2.9+0.?(RPL) und 4.2 ±0.2 (MWF) bezeichnen.Diagramme iltusirant les changementsdu niveau de I'attache (attachmentlevel) - perte (loss) ou gain - entreI'Examen Initial (Baseline) et I'examende controle de 6 mois. Les valeursinitiates de la profondeur de sondagesont marquees sur I'axe des X. Lesdroites de regression iUustrant I'effet dudetartrage et polissage des surfacesradiculaires (RPL) et celui du traite-ment chirurgical {MWF) eoupent I'axedes X a des points representani desprofondeurs initiates de sondage dc2.9±0J mm (RPL) et 4.2±0.2 mm(MWF).

Effect of plaque on attachment levels during thehealing phaseThe CPD-values for sites with Plaque Index 0 atthe 6-month examination were 2.7 mm ±0.3(RPL) and 4.2 mm±0.2 (MWF). The corre-sponding values for sites which at the 6-monthexamination received a Plaque Index score > 0were 4.3 mm±0.6 (RPL) and 4.9 mm±0.4(MWF). Finally, sites with Plaque Index score 2and 3 at the 6-month examination receivedCPD-vaiues of 5.1 mm±1.3 and 7.3 mm±2.6for the two modes of therapy respectively. It is

obvious that for each modality of active therapythe CPD-value increases with increasing plaquescores. In other terms, if the plaque scoreassessed at the 6-month examination is repre-sentative of the oral hygiene conditions duringthe phase of healing, the CPD-value obtainedfor a given site is dependent not only on theinitial probing depth but also on presence orabsence of plaque during healing.


Table I. Slope and critical probing depths (CPD) of regression lines calculated using initial probing depthas the independent variable and change in attachment level during the healing phase as the dependent variableNeigung der Regressionslinien und kritisehe Sondierungstiefen (CPD). bei deren Errechnung die Sondierungstiefeals unabhangige Variable und die Veranderung des Attaehmentniveaus wahrend der Heilungsphase ais abhangigeVariable dienteProfondeurs de sondage critiques (CPD) et penie (s/ope) des droites de regression calculees en utilisant laprofondeur de sondage initiale eomme variable independante et le changement de niveau de rattache pendant laphase de guerison comme variable liee

Treatment

MWFRPL

MWFRPL

MWFRPL

MWFRPL

MWFRPL

MWFRPL

MWFRPL

Teeth

AllAll

IncisorsIncisors

PremolarsPremolars

MolarsMolars

AllAll

AllAll

AllAll

Sites

AllAll

AllAil

AllAll

AllAll

BuccalBuccal

Interpr.Interpr.

LingualLingual

Slope

0.42±0.04*0.20±0.04

0.41 ±0.070.26±0.O7

0.36 ±0.080.18±0.07

0.46±0.070.19±0.06

0.46±0.090,35±0.08

0.35 ±0.090.16±0.I0

0.54±0.150.2S±0.15

CPD

4.2±0.2*2.9±0.4

4.1±0.32.7±0.5

4.7±0.42.5±0.9

4.1 ±0.33.5±0.8

4.1±0.42.8±0.4

4.2±0.52.5±1.9

4.2±0.63.l±1.5

1-1

0.590.34

0.560.42

0.560.35

0.630.31

0.600.53

0.490.25

0.740.49

* Slope or critical probing depth (CPD)±95% confidence intervalTreatment (Behandlung. traitement), teeth (Zahne. dents), sites (Regionen. loealisations). slope (Neigung. pente).

Probing depth and attachment level alterations nance phase was insignificant for both modali-during the maintenance phase ties of initial therapy (MWF= —0.26 mtn±0.2,Table 2 presents sites within the MFW- and RPL=-0 .29 mtn±0.!5).RPL-groups which at the 6-month reexamina- Table 3 describes the sites which at the 6-tion had a probing depth < 4 mtn (i.e. PD<4 month reexamination had a probing depthmm at 6 months= 100%). At the Baseline between 4 and 6 mm (PD=4-6 mm at 6CTammanon 54% (MWF)and58%(RPL)were months=100%). 63% of these sites were al-already in this probing depth category while ready in this category of probing depths at the37% (MWF) and 39% (RPL) were in the initial examination while between 37% (MWF)category of 4-6 mm of probing depth. The and35%(RPL)ofthesiteswereinitiallydeeper.corresponding figures for probing depths > 6 During the tnaintenancephase, around 60-70%mm were 8% (MWF) and 3% (RPL). During of these sites remained within the 4-6 mmthe maintenance phase around 90% ofthe sites category of probing depths while around 30%treated by either modality remained in the entered into the < 4 mm category. Only be-probitig depth category of < 4 mtn, while tween 1-4% of the sites developed into deeperaround 10% became deeper. The attachment pockets. Also in this category of initial probinglevel change for these sites during the mainte- depths, the attachment level change during the


ALTERATIONS: BASELtNE-REEXAMINATION6 MONTHS

maintenance phase was insignificant for bothmodalities of therapy (MWF=-0.08 mm±0.2, RPL=+ 0.05 mm±0.15).

Table 4 shows the sites within the MWF- andRPL-groups which at the end of the healingphase, i.e. at the 6-month reexamination, had aprobing depth >6 tnm (PD>6 mm at 6 months= 100%). At the Baseline examination, 20%(MWF) and 32% (RPL) of these sites were inthe 4-6 mm category while 80% (MWF) and68% (RPL) belonged to the >6 mm class ofprobing depths. During the maintenance phase,27-60% of this group entered into the 4-6 mmor <4 mm category of pockets while around40-50% remained unchanged. In sites whichwere in the >6 mm category at the 6-monthreexamination there was a significant gain of

Fig. 2. Diagram illustrating the gainand loss of attachment (Y-axis) inincisors, premolars and molars calcu-lated from measurements made at theBaseline examination and the reexam-ination after 6 months. RPL = scalingand root planing. MWF= modifiedWidman flap surgery. The initialprobing depth values are presented onthe X-axis. The non-surgical approachof therapy (RPL) consistently yieldedlower critical probing depth (CPD)values than the surgical approach(MWF) of therapy.Das Diagramm zeigt den Gewinn undden Verlust des Attachments fOrdinaie= Y-Achse) bei Inzisiven. Pramolarenufid Molaren nach 6 Monaten. errech-net aus den Werten der Ausgangsunter-suchung und der Nachuntersuchung.RPL=Zahnsteinentfernung und Wur-zclgidtiung. MWF—modifizierte Lap-penehirurgie nach Widman. Die ur-spriinglichen Sondierungstiefen sindauf der Abzisse (X-Achse) abgesetzt.Bei der nichl-chirurgischen Therapie-variante (RPL) lagen immer geringereWerte fiir die Sondierungstiefen vor alsbei der chirurgisehen (MWF) Behand-lungsfortn.

Diagramme illustrant le gain et laperiede I'atiache (axe des Y) des incisives.premolaires ei moiaires, calculhdapres ies mesures faites a VExamenInitial et a I'examen de eonirole 6 moisapres. RPL = deiartrage et polissagedes surfaees radieulaires. MWF—ope-ration a iambeau de Widman modifiee.Les valeurs de la profondeur initiale desondage sont presentees sur i'axe des X.Les valeurs critiques de la profondeurde sondage trouvees pour la methodenon chirurgicale (RPL) eiaient regu-lier^ent inferieures aux vaieurs cri-tiques trouvees pour la methode chi-rurgicaie (MWF).

attachment dtiring the maintenance periodwhich varied between 1.6 mm±0.8 (MWF) and1.2 mm±0.7 (RPL).

Tables 2, 3 and 4 indicate that shallow pock-ets tended to lose, while deeper sites tended togain attachment during the maintenance phase.


Fig. 3. Diagram illustrating gain orloss of attachment between the Base-line examination and the reexamina-tion after 6 months following surgical(MWF) and non-surgical (RPL) modeof therapy. The critical probing depthvalues for bueeal(B). interproximal (I)and lingual (L) surfaces varied he-tween 4.1 and 4.2 mm (MWF) and2.5-3.1 mm (RPL).Das Diagramm veransehaulieht Ge-winn oder Verlust von Attaehment zwi-schen der Ausgangsuntersuehung undder Nachuntersuehung nach 6 Monatenbei ehirurgischer (MWF) und nicht-ekirurgiseher Therapieform. Die Werteder kritischen Sondierungstiefe farbukkale (B), approximale (1) und lin-guale (L) Zahnoberflaehen variierteZKisehen 4.1 und 4.2 mm (MWF) und25-11 mm (RPL).

Diagramme illustrant le gain ou la perted'attache prenant place entre 1'ExamenInitial et I'examen de eontrole 6 moisapres ie traitement par methode chirur-gicale (MWF) et par methode non chi-rurgicale (RPL). Les valeurs critiquesde la profondeur de sondage pour lesfaces vestibulaires (B), interproxi-males (I) et linguales (L) variaient entre4.1 et 4.2 mm (MWF) et entre 2.S-3.Imm (RPL).

GAIN{mm)

ALTERATIONS: BASELINE-REEXAMINATION

8 7 8INITIAL PROBING

DEPTH (mm)

RPL

Table 2. Distribution of sites at the Baseline examination and during maintenance which had a prohing depth of< 4 mm at the 6-month reexamination. Around 75-83% (RPL and MWF) of all sites examined had a probingdepth of < 4 mm at the 6-month reexamination

Die Vorkommenshauftgkeit von Regionen (Ausgangsuntersuehung und Nachsorge). bei denen anlasslieh der Naeh-mtersuchung naeh 6Monaten eine Sondierungstiefe von <4 mm registrieri wurde. Etwa 75-83% (RPL undMWF)aller untersuchter Regionen hatten bei der Nachuntersuchung nach 6 Monaten eine Sondierungstiefe von <4 mmDistribution, a I'Examen Initial (Baseline) et pendant la phase de malntien, des loealisations ayant une profondeur desondage <4 mm a I'examen de controle de 6 mois. Environ 75-83% (RPL et MWF) de toutes les loealisationsexaminees avaient a I'examen de 6 mois une profondeur de sondage <C4 mm

<4 mmMWF4-6 mm >6 mm <4 mm

RPL4-6 mm >6 mm

Baseline6 months

12 months24 months

54%100%

Attachment level change6-24 months

37%

-0 .26 mm±0.2

58%100%

91%9 1 %

N.S.

39%

8%10%

-0 .29 mm±0.15

Attachment level change (Anderung des Attaehmentniveaus. changement du niveau de f attache).

330 LINDHE, SOCRANSKY, NYMAN, HAFFAJEE AND WESTFBLT

Table 3. Distrihution of sites at the Baseline examination and during maintenance which had a probing depthof 4-6 mm at the 5-month reexamination. Around 18-25% (MWF and RPL) of all sites examined had aprobing depth of 4-6 mm at the 6-niQnth reexamination

Die Vorl<ommenshaufigkeit von Regionen (Ausgangsuntersuchung und Nachsorge), bei denen aniasslich derNachuntersuchung nach 6 Monaten eine Sondierungstiefe von 4-6 mm registries wurde. Bei etwa 18-25%(MWF und RPL) aller untersuchter Regionen wurde bei der Nachuntersuchung nach 6 Monaten eine Sondierungs-tiefe von 4-6 mm gemessen

Distribution, a tExamen Initial et pendant la phase de maintien, des localisations ayanr une profondeur desondage de 4-6 mm a I'examen de controie de 6 mois. Environ IS-25% (MWF et RPL) de loutes leslocalisations examinees avaient a I'examen de 6 mois une profondeur de sondage de 4-6 mm

Baseline6 months

12 months24 months

Attachment level6-24 months

< 4 mm

_-

28%29%

change

MWF4-6 mm

63%100%71%69%

-0 ,08 mm±0,2

> 6 mm

37%-1%2%

N,S,

< 4 mm

2%_

27%32%

RPL4-6 mm

63%.100%70%64%.

+ 0,05 nim±0,15

> 6 mm

35%.._

3%:4%

Attachment level change (Anderung des Attachmentniveaus, changement du niveau de I'attache).

The mode of therapy used during active treat- mm, and > 6 mm for the two modalities of

ment did not significantly influence the altera- initial therapy (MWF and RPL) as assessed by

tion ofthe attachment level during the mainte- clinical examinations at 6, 12 and 24 months,

nance phase. Table 5 reports alterations of probing depths

and attachment levels at sites which at the 6-,

Effect of plague on probing depths and attach- 12-and 24-month reexaminations received a PlI

ment levels during the maintenance phase score of 0 while Table 6 reports corresponding

Tables 5 and 6 describe the percentage distribu- alterations at sites with PII scores >0 , Towards

tion of sites with probing depths of < 4 mm, 4-6 the end of the period of healing, i,e, at the 6-

Table 4, Distribution of sites at the Baseline examination and during maintenance which had a probing depth of>6 mm at the 6-month reexamination, it should be observed that only 1-2% of ali sites examined at 6 monthshad probing depths >6 mm

Die Vorkommenshaufigkeit von Regionen (Anfangsuntersuchung und Nachsorge), bei denen aniasslich derNachuntersuchung nach 6 Monaten eine Sondierungstiefe von > 6 mm registriert wurde, Beaehten Sie, dass nurbei 1-2% aller untersuchter Regionen nach 6 Monalen Sondierungstiefen von >6 mm gemessen wurdenDistribution, a f Examen Initial et pendant la phase de mainiien, des loealisations ayant une profondeur de sondage>6 mm a I'examen de controie de 6 mois, II convient de rentarquer que 1-2% seulement de toutes tes localisationsexaminees avaient a Fexamen de 6 mois des profondeurs de sondage >6 mm

MWF RPL< 4 mm 4-6 mm > 6 mm < 4 mm 4,-6 mm > 6 mm

Baseline - 20% 80% - 32% 68%6 months - - 100% - - 100%

12 months - 40% 60% - 27% 73%24 months - 60% 40% 5% 48% 48%

Attachment level change6-24 months +L6mm±O,8 N,S, -l-l,2mm±0,7

Attachment level change (Anderung des Attachmentniveaus, changement du niveau de I'attache),


Table 5. Distribution of sites with probing depths of < 4 mm, 4-6 mm, > 6 mm which at the 6-, 12- and24'month reexaminations had a Plaque Index score of 0

Die Vorkommenshaufigkeit von Regionen mit Sondierungstiefen von <i4 mm, 4-6 mm, > 6 mm, bei denenaniasslich der Nachuntersuchungen nach 6, 12 und 24 Monaten die Plaqueindex Beurteilungseinheit (score) von 0registriert wurde

Distribution des localisations qui avaient un score deO pour 1'Indice de Plaque aux examens de controie de 6,12 et 24mois, suivant la profondeur de sondage: < 4 mm, 4-6 mm, >(5 mm

MWF RPL<4 mm 4-6 mm > 6 mm < 4 mm 4-6 mm > 6 mm

6 months 93% 7% - 82% 17%12 months 94% 6% - 85% 13% 1%24 months 91% 9% - 84% 14% 1%,

Attaciinsent level change6-24 months -0.16 mm±0,l2 N,S. -0,18 mm+0.!4

Attachment level change (Anderung des Attachmentniveaus, changement du niveau de I'atiache).

month reexamination, 93% (MWF) and 82% which at the 6-, 12- and 24-month reexamina-(RPL) of plaque free sites had a probing depth tion harboured plaque were associated withof < 4 mm, while7% (MWF)and 17% (RPL) of deeper probing depths than the correspondingthe sites were in the 4-6 mm category. These plaque free sites (Table 5), Thus, while aroundfigures demonstrate that surgical therapy was 45-60% of the sites which had Piaque Indexsomewhat more effective than scaling and root scores > 0 belonged to the 4-6 or > 6 mmplaning alone in establishing sites with prohing categories, only 6-15% ofthe plaque free sitesdepths of < 4 mm. During the maintenance (Table 5 j belonged to this category of pockets,period there was in both groups almost no Furthermore, sites with plaque scores > 0 at thechange in the percentage of sites with probing 6-, 12- and 24-month reexaminations lost at-depths < 4 mm. Sites in either the MWF-group tachment during the maintenance period. Theor the RPL-group showed no significant change degree of clinical attachment loss varied be-in the attachment levels between the 6- and 24- tween —0,72 mm±0,2 (MWF) and —0,55 mmmonth reexaminations. Table 6 shows that sites ±0,15 (RPL), The difference in attachment

Table 6, Distribution of sites with probing depths of <4 mm, 4-6 mm, > 6 mm which at the 5-, 12- and24-month reexaminations had a Plaque Index score > 0

Die Vorkommenshaufigkeit von Regionen mit Sondierungstiefen von <4 mm, 4-6 mm, >6 mm, bei denenaniasslich der Nachuntersuchungen nach 6, 12 und 24 Monalen eine Plaqueindex Beurteilungseinheil (score)von >0 registriert wurde

Distribution des localisations qui avaient un score >0 pour I'Indice de Plaqueaux examens de controie de 6, 12 et24 mois, suivant la profondeur de sondage: < 4 mm, 4-6 mm, ><S mm

MWF RPL< 4 mm 4-6 mm > 6 mm < 4 mm 4-6 mm >6 mm

6 months 55% 45% - 41% 53% 7%12 months 37% 61% 2% 44% 43% 13%24 months 51% 46% 3% 44% 47% 9 % '

Attachment level change6-24 months -0,72 mm±0,2 N,S, -0,55mm±0,15

Attachment level change (Anderung des Attachmentniveaus, changement du niveau de Fattache),


level alterations between plaque free and plaqueharbouring sites was statistically significant{P<0.05).

Discussion

Previous investigations describing the effect oftherapy on patients with periodontal diseasehave shown that while sites with initially deeppockets tend to gain clinical attachment, siteswith initially shallow pockets tend to loseattachment (Ramfjord et al. 1973, 1975, 1980,Knowles etal. 1979, 1980, Pihlstrom etal. 1981,Lindhe et al. 1982). In the present study re-gression analysis was used to identify so-calledcritical probing depths, i.e. initial probingdepths of sites from different groups of teethand tooth surfaces below which loss of clinicalattachment is likely to occur and above whichattachment gain often results. By this analysis itwas found that the critical probing depth value(CPD) for scaling and root planing used alonewas significantly smaller than the correspond-ing value for scaling and root planing used incombination with the modified Widman flaptechnique of surgery. The slopes of the regres-sion lines for the two modalities of therapydescribed in Fig. 1 also indicate, however, thatin sites with initial probing depths above theCPD-value more gain of clinical attachmentcan be expected to occur following Widmanflap surgery than following the non-surgicalmodality of therapy. On the other hand, thesurgical approach may result in more attach-ment loss than scaling and root planing alonewhen used in sites with initially shallow pockets.Thus, these findings indicate that in patientswith a large number of periodontal sites withshallow probing depths a non-surgical ap-proach of therapy may be preferable, while inpatients with a large number of deep pocketssurgical treatment may result in more gain ofclinical attachment. Findings reported byKnowles et al. (1979) and Pihlstrom et al. (1981)support this view.

In the present patient sample treatment in-

cluding the modified Widman flap techniquegave a CPD-value of 4.2 mm±0.2. It is interest-ing to observe that Knowles et al. (1979) andPihlstrom etal. (1981) using the same treatmenttechnique reported that attachment loss tendedto occur in sites with initial probing depths < 4mm, while attachment gain occurred in siteswith deeper initial probing depths. In addition,Knowles et al. (1979) found that more attach-ment gain was encountered in initially deep(7-12 mm) than in initially moderately deep(4-6 mm) pockets.

The critical probing depth values and theslopes of the corresponding regression lines forthe two modalities of therapy used have beendescribed for different groups of teeth and fordifferent tooth surfaces (Figs. 2 and 3; Table 1).The data reported make it possible, prior totherapy, to estimate the expected net gain orloss of attachment for a given tooth and modeof therapy in patients maintained on a properplaque control program. For example, at theinitial examination, a premolar tooth maydisplay the following probing depths: 1 mm(buccal), 6 mm (mesial), 2 mm (lingual) and 5mm (distal). If this tooth is subjected to atherapy which involves scaling and root planingin combination with Widman flap surgery, thefollowing attachment level alterations might beexpected to occur: buccal —1.4 mm, mesial+0.7 mm, lingual —1.2 mm, distal +0.2 mm,i.e. a net total loss of attachment of 1.7 mm. Ifthe same tooth is subjected to scaling and rootplaning only, a net total attachment gainamounting to +0.1 mm might be expected.While the above example may not be valid foragiven tooth in a given patient it suggests that theregression analysis approach may be used as aguide to the overall effect on the clinical at-tachment level of certain treatment procedures.Clinical trials are presently being performed onpatients with advanced periodontal disease inan attempt to identify critical probing depthsand regression lines for different modalities ofperiodontal surgery.

The data presented in Tables 2, 3 and 4 clearly


demonstrate that the probing depths obtainedfollowing active therapy and healing (i.e. at 6months in the present study) can be maintainedunchanged or reduced further during a mainte-nance care period involving careful prophylaxisonce every 3 months. Obviously, the non-surgical mode of therapy (RPL) was not aseffective as root planing combined with Wid-man flap surgery in establishing sites afterhealing with probing depths < 4 mnn (Lindhe etal. 1982). However, the attachment level altera-tions during the maintenance phase were moreor less the same in the two treatment groups andevidently unrelated to the method of treatmentused during active therapy. These fmdings arein agreement with the results presented byLovda! et al. (1961). Alexander (1969), Hughes& Caffesse (1978), Hellden et al. (1979), Torfa-son et al. (1979), Morrison et al. (1980), Bader-sten et al. (1981) and Pihlstrom et al. (1981),showing that scaling and root planing com-bined with oral hygiene measures have thepotential to reduce inflammation and probingdepths. Badersten et aL (1981) studied the effectof non-surgical therapy on moderately ad-vanced periodontitis and concluded that non-surgical therapy can be successful even in siteswith 4-7 mm pockets. The findings reportedfrom the present study are, however, in variancewith results by Walker & Ash (1976), Waerhaug(1978), Rabbani et al. (1981) and Tabita et al.(1981) who claimed that root surfaces of siteswith probing depths of > 3 mm even afterextensive scaling and root planing containedmicroscopic amounts of plaque and calculus.Waerhaug (1978) stated: "if the pocket rangesfrom 3-5 mm the chances of failure are greaterthan the chances of success, and if the pocketdepth surpasses 5 mm, the chances of failuredominate". In the present study as in the trialsreported by Ramfjord and coworkers (for re-view see Knowles et al. 1979) and by Lindhe &Nyman {1975) no attempts were made except byclinical probing to assess the presence of cal-culus or subgingival plaque at various treatedsites during the nnaintenance period. Findings

reported by Listgarten et al. (1978) make itreasonable to assume, however, that perio-dontai sites with probing depths > 3 mm fol-lowing therapy may harbour a subgingivalmicrobiota dominated by coccoid cells andnon-motile short rods. If this was the micro-biota detected on the root surface of extractedteeth, it may be compatible with gingival healthand maintained attachment levels (Listgarten etal. 1978). Hence, it must be questioned if themere presence of microorganisms on a treatedroot surface should be used as a measureindicative of failure of therapy.

The present study indicates that the level oforal hygiene established during healing andmaintenance is more critical for the resultingprobing depths and attachment levels than themode of initial therapy used. Thus, sites whichduring the maintenance period were found to bedevoid of clinically detectable supragingivalplaque (Table 5) were associated with probingdepths of < 4 mm. In contrast only 30-50% ofsites which harboured plaque belonged to the< 4 mm category (Table 6). Furthermore, whileplaque free sites showed no or little attachmentloss, plaque infected sites lost on the averagebetween 0.72 and 0.55 mm of attachment duringthe 18 months of maintenance. These fmdingsare in close agreement with Rosling et al. (1976)and Nyman et al. (1975, 1977) and illustrateanew that the quality of the maintenance care isof critical importance for the long-term result oftreatment of periodontai disease.

Zusammenfassung

"Kritische Sondierungstiefen" bei parodomaler Thera-pieDie hier vorlieg:nde Untersuchung wurde an !5Probanden durchgefuhrt, die zur Behandlung fort-geschrittener parodontaler Krankheit ubenvlesenworden waren. An alien Patienten wurde zuersteinmal cine Ausgangsuntersuehung vorgenommen, dieeine Beurteilung der oralen Hygiene und des gingi-valen Status, sowie Messungen der Sondierungstiefenund der Attaehmentniveaus beinhaltete. Danachwurden die Patienten uber ihren oralen Status unter-richtet, in oralen Hygienemassnahmen unterwiesen


und dann nach emem "split mouth" Behandlungs-modell (underschiedlicher therapeutischer Einsatz an"halben Zahnbogen") parodontal behandelt. An dereinen Kieferseite wurden, bei gleichzeitiger modifi-zierter Widman Lappenoperation, der Zahnstein ent-fernt und dann die Wurzeln geglattet. An den kon-tralateralen Kieferquadranten beschrankte sich dertherapeutische Einsatz ausschliesslich auf Zahnstein-entfernung und Wurzelglattung, Die Zeitspanne vonder Initiaibehandiung bis 6 Monate nach dieserBehandlung wurde als Heilungsphase und die Periodevom 6. bis zum 24, postoperativen Monat als die dasHeilungsergebnis aufrechterhattende Phase bezeich-net, Wahrend der Heilungsphase wurden die Pa-tienten jede 2. Woche zu professioneller Zahnrei-nigung einbestellt, Wahrend der aufrechterhaltendenPhase betrugen die Intervalle zwischen den Einbe-stellungen zur Nachsorge 3 Monate, 6, 12 und 24Monate nach Abschluss der aktiven Behandlungwurden Nachuntersuchungen vorgenommen.

Die Resultate zeigten, dass die Behandiung inRegionen mit eingangs flachen Taschen ru Verlust anklinischem Attachment fCihrte, wahrend Regionenmit ursprtinglich tiefen Taschen klinisches Attach-ment gewannen, Mit Hilfe einer Regressionsanalysewurden fur die beiden hier angewendeten Behand-lungsmethoden "kritische Sondierungstiefen" ermit-telt, Es zeigte sich, dass der kritische Sondierungswertfur Zahnsteinentfernung und Wurzelplanung signifi-kant geringer war als der entsprechende Wert ftirZahnsteinentfemung und Wurzelglattung bei gleich-zeitiger modifizierter Widman'scher Lappenopera-tion (2,9 gegenuber 4,2 mm), Weiterhin hatte, beieingangs flachen Zahnfleischtaschen, die chirurgischeTherapievariante mehr Attachmentveriust 7iir I "tjcals die nicht-chirurgische Behandlung, Andererseitsstellte sich - bei Sondierungstiefen uber dem kri-tischen Sondierungswert - nach Widman'scher Lap-penoperation ein hoherer Attachmentgewinn ein alsnach nicht-chirurgischer Behandlung durch Zahn-steinentfemung und Wurzelglattung,

Die Daten der Nachuntersuchungen, 12 und 24Monate nach der aktiven Behandlung zeigen, dass dienach aktiver Tharapie vorgefundenen Sondierungs-tiefen und Hohen der Attachmentniveaus wahrendder aufrechterhaltenden Behandlungsphase (Nach-sorgeperiode), mit sorgfaltigen Prophylaxebehand-lungen in 3-monatlichen Intervallen, sogut wie unver-andert blieben. Die Daten zeigen jedoeh gleichfalls,dass das Niveau eigener oraier Hygiene wahrend derHeilungs- und aufrechterhaltenden Phase mehr furdie sondierbaren Taschentiefen und Attachmentni-veaus bedeutete, als die initial angewendeteTherapie-variatite. So wurde an Regioneti mit supragitigivalerPlaquefreiheit wahrend der Nachsorgeuntersuehun-gen. flache Taschen und unveranderte Attachment-niveaus gefunden, Im Gegetisatz dazu wurde inRegionen mit Plaquedepositionen, sich erhohende

Werte fur Sondierungstiefen und weitergehender At-tachmentverlust konstatiert.

Resume

"Profondeun de sondage critiques^ dans les traite-ments parodontauxLa presente etude a porte sur 15 sujels qui nousavaient ete adresscs pour traitement de parodonto-pathies a un degre avance. Tous les patients ontd'abord subi un Fxamen initial comportant I'enre-gistrement de l'etat des gencives et du niveau deI'hygiene bucco-dentaire, et la mesure de la profon-deur des culs-de-sac lors du sondage et des niveaux deI'attache. Apres avoir refu des informationsdetailleessur leur cas et des instructions sur les mesuresd'hygiene bucco-dentaire, les patients ont regu untraitement parodontai suivant une technique debouche divisee. D'un cote de la machoire, on aeffectue detartrage et polissage des surfaces radi-culaires au cours d'une operation a iambeau suivantla technique de Widman modifiee, tandis que, dans lesquadrants controlateraux, le traitement se bornait afaire detartrage et pohssage des surfaces radiculaires.La periode ailant du traitement initial a 6 mois apresle traitement etait consideree comme phase de gueri-son. et la periode ailant de 6 a 24 mois apres letraitement etait consideree cotnmephase de maintien.Pendant la phase de guerison, les patients etaientconvoques pour an nettoyage professionnel des dentstotis les quinze jours. Pendant la phase de maintien,I'intervalle entre les rappels etait porte a 3 mois. Desexamens de controle etaient pratiques 6, 12 et 24 moisapres la fin du traitement actif,

Les resultats ont montre que ie traitement deter-minait une perte d'attache ciinique dans les locali-sations ou les poches etaient peu profondes a I'ori-gine, tandis que, au niveau des localisations ou lespoches etaient profondes a l'origine, I'attache cliniques'etait amelioree, Au moyen d'une analyse de regres-sion, on a calcule les "profondeurs de sondagecritiques" pour les deux methodes de traitement utiii-sees. La profondeur de sondage critique trouvee pourle traitement par detartrage et polissage des surfacesradiculaires etait significativement moins grande quela valeur correspondante trouvee pour le traitementou detartrage et polissage avaient lieu au cours del'operation a iambeau selon la methode de Widmanmodifiee (2,9 VS 4,2 mm). De plus, le traitement avecintervention chirurgicale donnait une perte d'attacheplus importante que la methode non chirurgicalelorsqu' on I'utilssait dans les localisations presentanta l'origine des poches peu profondes, Cependant onconstatait, dans les localisations au niveau desquellesla profondeur de sondage initiale depassait la valeurde la profondeur de sondage critique, un gain plusimportant d'attache clinique aprfcs l'operation 4 lam-


beau de Widman modifiee qu'apres detartrage etpolissage des racines.

Les donnees obtenues Jors des examens de controle12 et 24 mois apres le traitemenl actif montraient queles profondeurs de sondage et les niveaux d'attacheobtenus apres le traitement actif et la phase deguerison restaient plus ou moins inchanges pendant laduree du traitement de maintien comportant desseances de nettoyage minutieux tous les 3 mois.Cependant, il ressortait aussi des donnees que leniveau de i'hygiene bucco-dentaire maintenu par Jespatients eux-memes pendant la phase de guerison etpendant la phase de maintien etait d'une importanceplus critique pour la profondeur de sondage et leniveau de l'attache que la methode de traitementutilisee au debut. Ajnsi, les localisations au niveaudesquelles on constatait I'absenee de plaque supra-gingivaie pendant la phase de maintien presentaientdes poches peu profondeset maintenaient le niveau del'attache. Par contre, les localisations au niveaudesqueiles la plaque s'etait accumulee presentaientune augmentation de la profondeur des poches et de laperie d'attache.

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Address:

Departtnent of PeriodontologyFaculty of OdontologyUniversity of GothenburgBox 33070S-400 33 GothenburgSweden

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