kugelberg 1985 periodontal healing after exo wisdom

8/13/2019 Kugelberg 1985 Periodontal Healing After Exo Wisdom

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Int. Oral Surg. 1985: 14: 29-40 eywords: impaction; defects intrabony; surgery. oral; healing periodontal; molar third

eriodont l he ling fter imp ted lowerthird mol r surgeryA retrospective studyC RL F. KUGELBERG UL F AHLSTR


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30 KUGELBERG, AHLSTROM, ERICSON AND HUGOSONdesign had no influence on bone loss distalto the second molar, but could be associatedwith a decrease in distal pocketing. Otherauthors4 631 also suggested that flap designmight have an effect on future periodontalconditions, but studies by ST PH NS 2 8 andWOO et l 30 indicated that the decision touse any of the various flap designs for accessto mandibular third molars should be basedon operator preference rather than on theassumption that the periodontal health ofthe adjacent second molar willbe improved.

Some authors have studied other factorsaffecting the periodontal healing.ASH et l 4found that periodontal hazards involved inextracting third molars were reduced, andreformation of the alveolar bone crest wasenhanced, in young individuals in whom theroots of the third molars were not completely developed. ZlEGLER3 1 has confirmedthe results of ASH et l in a similar study.GRONDAHL LEKHOLM10 observed a reduction in pocket depth 12 months after surgical removal of lower third molars, but nosignificant change in the height of the supporting bone distal to the second molar.The lack of sufficient statistical evidenceon hazards of lower third molar surgeryresults in confusion among clinicians because benefit-risk ratios are estimated fromclinical impressions only. The NIH sympo-

sium on Third Molars in 197919 recommended that both short- and long-term studiesbe undertaken in a number of areas relatedto periodontal considerations.The aim of this investigation was to makea retrospective survey of the periodontalhealing of the adjacent second molar 2 yearsafter impacted lower third molar surgery.

teri l nd methodsThe study comprised 144 patients referred to theDepartment of Oral Surgery of the Institute forPostgraduate Dental Education, Jonkoping,Sweden, for removal of 215 mandibular thirdmolars . The impact ion surgery was performedduring a l-year period in 1978. All patientsfulfilled the following criteria:1. Preoperative history.2. Radiographic examination including panoramic radiography, posteroanterior cephalometric radiographs with the mouth open, and atleast 2 intra-oral X-ray films.3. Patient willing to participate and recall practicable.Of the 144 persons age range 16 to 53 yearsparticipating in this study, 73 had one third molarremoved and 71 had two third molars removed.No discrepancy existed in the age and sex distribution between those who had one or two molarsremoved . The distribution concerning angulationand degree of impaction was also equal. Of a totalof 215 third molars, 112 molars were from malesand 103 were from females Table 1 .

Table 1. Distribution of the 215 molars according to age and sex of the patientsAge-group Male Female Totalyears n ) n ) n ).s;20 14 12.5 16 15.5 30 14.0

21-25 30 26.8 30 29.2 60 27.926--30 41 36.6 23 22.3 64 29.831-35 16 14.3 24 23.3 40 18.6>35 11 9.8 10 9.7 21 9.8Total 112 100.0 103 100.0 215 100.0mean years 27.4 27.0 27.2S.D . 6 .33 6.41 6.35


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PERIODONTAL HEALING AND THIRD MOLARS 31Pre operative examinationBoth the extra-oral and intra-oral radiographswere taken in a standardised way. Philips Oralix65 and long-cone technique was used for theintra-oral examination. The intra-oral films wereexposed in 2 different projections, isometric andslight over-axial, with the central beam pointed atthe centre of the second molar and a focal-objectdistance of 20 em. The films were processed in astandardised manner in a developing machine.From the radiographs, the state of the alveolarcrest and the prevalence of intrabony defects wereestimated.Operation techniqueAll the patients were treated under aseptic conditions using local anaesthesia Xylocainew Adrenaline 20mg/ml, ASTRA; adrenaline 12.5 t1g/ml .The design of the soft tissue flap was either theclassical vertical flap or the envelope flap. Ostectomy and sectioning were performed with alow-speed rotary instrument under constant irri-

Fig 1. Landmarks used for clinical and radiographic measurements. A) indicates the free gingival margin, B) the cementa-enamel junction,C) the bottom ofthe pocket, and D) the alveolarcrest.

gation with sterile saline. After removal of thetooth, careful toilet of the extraction socket wasperformed, including removal of follicular remnants and granulation tissue, and also thoroughsaline lavage. Finally, the flap was repositionedand sutured.After week, the patient returned either to theDepartment of Oral Surgery or to the referringdentist for control and removal of sutures. Nofurther steps were taken e.g., increased oralhygiene etc.) to improve the healing.Post operative examinationThe post-operative examination took place 2years after the surgical treatment and includedboth clinical and radiographic variables. All examinations were made by the same investigatorCK).For the clinical and radiographic determinations, certain landmarks were used Fig. 1). Thedistance ACwas defined as the pocket depth. Thedistance BD represented the intrabony defect, i.e.,the post-operatively remaining intra-osseousdefect.The clinical recordings were carried out on thefirst and second molars adjacent to the extraction site. They comprised registration of dentalplaque, gingival health and probing depth for all

tooth surfaces. The presence of visibleplaque wasrecorded and corresponded to PlaqueIndex PU2 and 3 SILNESS LOB26) . The occurrence ofgingival inflammation was recorded according toGingival Index Gl) 2 and 3 LOE SILNESS17),i.e., moderate changes in texture and colourand/or bleeding on probing. Pockets exceeding 3mm were recorded with a periodontal probeMarquise), Measurements were made from thefree gingival margin to the bottom of the pocketto the nearest mm.As a complement to probing pocket depth,radiographs weretaken to evaluate the bone leveland the prevalence and depth of intrabony defects. The radiographic recordings were performed in the same way as at the pre-operativeexamination. A periodontal probe Marquis )with the handle cut-off served asan indicator, andwas placed at the bottom of the pocket distal tothe second molar. The final positioning of theprobe was not assessed until the probe had beenplaced along the entire distal surfaceto reach thedeepest part. Intra-oral X-ray films were thentaken, first with and then without the indicatorFig. 2).All the measurements on the radiographswere performed by the examiner at the end ofthe study. The radiographic material was studied


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32 KUGELBERG. AHLSTROM, ERICSON AND HUGOSON

ig 2. Periapical radiographs of the secondmolar2 years after lower third molar surgery with (A)and without (B) a periodontal probe as indicator.Patient : female, 29 years of age.

using observation binoculars according toMATTSSON18. The proximal bone levelwas determined according to BJORN HOLMBERG5. Atransparent plastic ruler with 10equidistant divisions was placed over the radiograph to estimatethe bone level in tenths of the total length of thetooth. The measurements were recorded in increments of half a division and multiplied by 10. Thedepth of the intrabony defect was obtained bymeasuring the distance between the cementoenamel junction and the bottom of the pocket,distance BD in Fig. 1, with the aid of a mmgraduated transparent plastic ruler.The inaccuracy of the radiographic methodsand the imprecision of the measurements wereanalysed and are presented in a separate report' .The results showed that the error variances due toexaminer inconsistency were between 3 and 4of the total variances and therefore contributedan insignificant amount.

Examination of the first molar was performedtocheck whether any changes had occurred otherthan those due to impaction surgery, such asmarginal periodontitis during the follow-upperiod. The effect of removal of the lower thirdmolar was evaluated by comparing the preoperative and post-operative recordings of theclinical and radiographic variables used.Statistical methodsFor related samples where measurements weremade on an ordinal scale, the sign test was usedfor statistical analysis.When the data consisted offrequencies in discrete categories, the X test wasused to determine the significance of differencesbetween 2 independent samples.An analysis of variance, concerning pocketdepths and intrabony defects, showed that theredid not exist any dependence between the twooperations in the samepatient. Each removal wastherefore regarded as a single observation.

sultsThe results are presented in Tables 2-10.

Of the 215 surgical removals of lowerthird molars post operative control wasmade by the referring dentist in 101 casesand by the Department of Oral Surgery in114 cases. Of the latter 114 cases, 30.7were treated on 2 or 3 further occasionsbecause of post operative symptoms ofvarying severity.Plaque Index Gingival Index and probingdepthThe results of the plaque registrations 2years post operatively are presented inTable 2. The distal and lingual surfaces ofthe f irst and second molars showed higherplaque scores than the other surfaces.16.7 of the l ingual surfaces of the firstmolar 36.3 of the lingual surfaces of thesecond molar and 25.6 of the dista l surfaces of the second molar showed a PlaqueIndex score of 2 and/o r 3, respectively. Thedistal surface of the second molar showed asignificantly higher plaque score than thecorresponding surface of the first molarip 0.001).37.5 of these surfaces in males


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4 KUGELBERG, AHLSTROM, ERICSON AND HUGOSONTable 5. Distribution of pocket depth PD) on the distal surface of the second molar in males andfemalesPD mm)malesfemales

::;4n )3 2.7)13 12.6)

5-6n )49 43.7)57 55.3)

7-8n )46 41.1)24 23.3)

n )14 12.5)9 8.7)

Totaln112103

Males versus females; 0.0 I.

5). This difference is statistically significantp


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PERIODONTAL HEALING AND THIRD MOLARS 35Table 8. Intrabony defects IBD) on the distal surface of the second molar pre-operatively and 2 yearspost-operatively

53 5 6-7 ;;::8 TotalIBD rom) n ) n ) n ) n ) npre-op.males 49 43.8) 29 25.9) 26 23.2) 8 7.1) 112females 76 73.8) 17 16.5) 9 8.7) 1 1.0) 103total 125 58.1) 46 21.4) 35 16.3) 9 4.2) 215post-op,males 64 57.1) 32 28.6) 13 11.6) 3 2.7) 112females 82 79.6) 16 15.5) 2 1.9) 3 2.9) 103total 146 67.9) 48 22.3) 15 7.0) 6 2.8) 215Males versus females pre-op.; P< 1Males versus females post-op.; p< 1Pre-op, versus post-op., total; < 0.001.

Table 9. Cross-tabulation of intrabony defectsIBD) on the distal surface of the second molarpre-operatively and 2 years post-operatively

Post-operatively

Pre-operatively53 112 9 I 3 1254-5 18 26 2 466-7 10 10 2 35~ 3 3 2 I 9Total 146 48 IS 6 215

Table 10shows the prevalenceand depthof intrabony defects at different ages at thetime of the surgical treatment pre-operatively and 2 years post-operatively. Of a totalnumber of 90 cases aged 25 years oryounger, 34 37.8 ) showed intrabony defects 4 mm pre-operatively. The corresponding figure2 years post-operativelywas18 20.0 ). Of a total number of 125 casesaged 26 years or older, 56 44.8 ) showedpre-operative defects ~ 4 mm, and 5140.8 ) showed defects ~ mm 2 yearspost-operatively.

or less than 3 rom, 4-5 mm, 6-7 mm, andequal to or exceeding 8 mm,As Table 8 shows, intrabony defects mm were present pre-operatively in 41.9 .The corresponding figure 2 years postoperatively was 32.1. Thus, almost t ofthe total material showed defects equal to ordeeper than 4 mm postoperatively. Thedistribution of defects ~ 4 rom between menand women was similar pre- and postoperatively. 70 of the intrabony defectswere found among men and 30 amongwomen.A cross-tabulation of intrabony defectspre-operatively and 2 years post-operativelyis presented in Table 9. Pre-operatively, 90cases exhibited intrabony defects 4 rom.Of these defects, 49 showed a decrease indepth, and remained unchanged or increased in depth post-operatively. Of a totalof 125 cases with preoperative intrabonydefects S 3 mm, 112 showed defects withinthis limit and 13 showed defects 4 rom 2years post-operatively. Among the former112cases, an increase in depth of the intrabony defect was registered in 46 cases, nochange in 53 cases and a decrease in 13cases.

IBD rom) s 3 4-5 6-7 2: 8 Total


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36 KUGELBERG, AHLSTRl>M, ERICSON AND HUGOSONTable 10. Intrabony defects IBD) on the distal surface of the second molar pre-operatively and 2 yearspost-operatively in relation to ageIBD mm) 4-5 6-7 TotalAge years) ) ) ) ) pre-op.s20 17 56.7) 8 26.7) 5 16.6) 3021-25 39 65.0) 11 18.4) 8 13.3) 2 3.3) 6026-30 35 54.7) 14 21.9) 12 18.7) 3 4.7) 6431-35 25 62.5) 9 22.5) 3 7.5) 3 7.5) 40>35 9 42.9) 4 19.0) 7 33.3) 1 4.8) 21post-op,:;;;2 25 83.4) 4 13.3) 1 3.3) 3021-25 47 78.3) 10 16.7) 3 5.0) 6026-30 39 61.0) 15 23.4) 5 7.8) 5 7.8) 6431-35 28 70.0) 11 27.5) I 2.5) 40>35 7 33.3) 8 38.1) 5 23.8) 1 4.8) 21

ig 3. Periapical radiographs of the third molar region. Pre-operatively A) and 2 years postoperatively B). Patients: male aged 36 years left) and male aged 20 years right).


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PERIODONTAL HEALING AND T IR MOLARS 37

is ussionThe age and sex distribution in the 144patients taking part in this retrospectivestudy were typical of those of a clientelereferred to a specialist clinic in Sweden forsurgical removal of impacted lower thirdmolars.The pre- and post-operative measurements of periodontal healing were mainlybased on radiographic registrations, asprobing depth measured from the gingivalmargin seldom corresponds to sulcus orpocket depth. The discrepancy is least in theabsence of inflammatory changes but increases with increasing degrees of gingivalinflammation. Decreased probing depthmeasurements following periodontal thera-

py may be due to decreased penetrability ofthe gingival tissues by the probe .The results of this study of the effect oflower third molar surgery on periodontalhealingof the adjacent secondmolar show ahigh rate of remaining deepened pocketsand intrabony defects. Thus, 43.3% of thepatients demonstrated probing depths 7mm, and 32.1% showed intrabony defects

4 m 2 years post-operatively. In apparently similar pre-operative circumstances,third molar removal sometimes resulted inlarge post-operative intrabony defects andsometimes not (Fig. 3). The defects could beeither fairly wide or very narrow (Fig. 4).As a rule, the males showed a higherincidence of plaque and gingivitis at thedistal surface of the second molar than the

ig 4. Periapical radiographs of the third molar region. Pre-operatively (A) and 2 years postoperatively (B). Patients: male aged 21 years (left) andmale aged 20 years (right).


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38 KUGELBERG, AHLSTROM, ERICSON AND HUGOSONfemales. There was also a male dominanceconcerning deepened pockets ~ mm). Ofthe cases with deep probing defects, justover 20 showed pseudopockets, while therest demonstrated intra-osseous defects corresponding to the probing depth.Healing of intrabony defects after different types of periodontal surgery has beenpresented by ADELL1, ELLEGARD LOEBPOLSON HBIJL24 and ROSLING25. All ofthese investigators point out the conditionsfor regeneration, viz. optimal treatment ofthe root surface and the adjacent soft tissue, followed by meticulous post-operativeplaque control.

The post-operative plaque scores indicatethat the level of plaque control on the distalsurface of the second molar of most of theparticipants was not optimal. Only a few ofthe patients were plaque-free on this surface.With extreme emphasis on plaque contro124.2s, and continuously plaque-freeteeth, improved healing might have beenaccomplished, but in this study, the participants had not been subjected to increasedoral hygiene or special surgical proceduresin an attempt to improve healing.

oth GROVES MOORE9 and SZMYD HESTER29 demonstrated post-operative reoduction in pocketing, which is in agreementwith the findings of GRONDAHL LEK-HOLM10 One of the explanations could bethat these authors studied younger individuals, with a mean age of 23-24 years, whilethis study comprised patients aged around27 years. However, in agreement with thisstudy, ASH et al and ZIEGLER 3 1 found ahigh incidence of pocketing distal to thesecond molar both pre- and postoperatively. The results of a study by OsBORNE et al 2 3 support the finding of ASH etal: that root planing of adjacent secondmolars seemed to be of minimal value inreducing crevicular depth or in inducingnew attachment at or near original levels.ncases where the root cement has not been

exposed to microbial influence from thedental plaque, wound healing seems tooccur without loss of tissues, and with resti-tutio ad integrum as the final result27. But incaseswith marginal periodontitis, the possibilities of complete regeneration of the tissues are entirely different. Phenomenawhichmay jeopardise new connective tissueattachment to root surfaces are apical migration of junctional epithelium with theestablishment of long epithelial attachment,and regrowth of subgingival plaque withresulting chronic inflammationll.16.27.In a recent study, NYMAN et al 2 2 demonstrated that cement formation and new connective tissue attachment did not occur onroot surfaces previously exposed to periodontal pockets and subsequently to scalingand root planing, or on root surfaces surgically deprived of their supporting bone andpreviously unexposed cement layer. Thenew attachment between the gingiva and theroot was established by epithelium.These are all factors to consider in casesof impacted lower third molar surgery,where intrabony defects, due to the tooth'srelation to the adjacent second molar, oftenseem to occur. Since specific types of bacteria seem to be associated with periodontaldisease, the intrabony defects observed inthis study may verywell be explained by theestablishment of a particular pathogenflora1 2o As the distal surface of the second molar always seems to show a higher

plaque score than other surfaces, it might bea locus minoris for development of localperiodontitis.The least traumatic way to remove animpacted or semi-impacted tooth is by reflecting a flap, removing bone and dividingthe tooth into sections. Careful use of elevators and forceps is just as important asjudicious ostectomy in preservation of thealveolar bone crest. In this study, the removal of bone was performed under a generous flow of saline to minimise the risk of


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PERIODONTAL HEALING AND THIRD MOLARS 39devitalising the bone by heat, as all devitalised bone is resorbed or sequestered. Inspite of this precaution, loss of interproximal bone distal to the adjacent secondmolar was found in over 40 of 112 caseswhich pre-operatively exhibited intrabonydefects ::;3 mm (Table 9). This figure mustbe considered a result of the surgical technique, where one, or more likely several, ofthe above-mentioned factors have to someextent affected the bone loss.

GROVES MOORE 9 demonstrated boneloss in about 25 of cases irrespective of theflap design. The same incidence was foundwhether the lower third molar was nonerupted or erupted at the time of extraction.They also postulated that third molar removal may prevent further deterioration ofthe periodontal health of the adjacent second molar . Some authors 10 ,2 3 have foundthat extraction of the third molar does notappear to cause any change in the height ofthe supporting bone distal to the secondmolar while ASH et al. and ZIEGLER31, inagreement with this s tudy, clearly demonstrated the presence of post-operative intrabony defects. In an unspecified group ofelderly patients with third molars, GRON-DAHL LEKHOLM10 occasionally found amarked reduction of the supporting bonytissue at the distal surface of the secondmolar. Although ASH et al.4 only followed86 of the original 225 cases for 2 years, theyfound, in agreement with this study, thatafter the early twenties the risk of loss ofperiodontal support of second molarsseemed to be significantly greater after extraction of adjacent third molars than whenthey were retained.

The National Insti tutes of Health Consensus Conference on ThirdMolars-? statedthat third molars should be removed in theyounger patient where indicated becausethere is less transitory or permanent morbidity. Table 10 emphasises this, as in theyounger group there was an almost 50

reduction in the number of pathologicalintrabony defects, while only a fewshowed complete periodontal healing in theolder group. These results suggest that incases where the need for extraction can beforseen, early removal of the third molarmight have a beneficial effect on theperiodontal health of the adjacent secondmolar. ZIEGLER 31 found that there was noattachment loss I year after removal ofimpacted third molars in 15 patients aged13-16 years.

Pocket formation and intrabony defectsoccurred most frequently and were mostsevere when the crown of the third molarwas in close approximation to, or apparentcontact with, the second molar. Similar findings have been noted by otherauthors4 ,6 ,31 . The size of the contact areaseemed to be well correlated to the inclination of the third molar .To elucidate the significance of conceiv

able factors in relation to the ultimate healing after lower third molar surgery, 7variables have been computerised for multiple and stepwise analysis of regression andthe results will be presented in a subsequentstudy.Acknowledgements - The authors would like tothank Dr. Rolf Karlsson for assistance withstatisticalanalysis Thisstudy hasbeensupportedby the Swedish Dental Society and the CountyCouncil of Jonkoping,

eferen es1. ADELL, R.: Regeneration of the periodontium. An experimental study in dogs. Thesis.Gothenburg, Sweden Scand. Plastic andReconstr. Surg. 1974: suppl. 11.2. App G. R. STEPHENS R. J.: Periodontalconsiderations and the impactedtooth. Dent.Clin. North Am. 1979: 23: 359-367.3. ASH M.: Third .molars as periodontalproblems Dent. North Am. 1964: 18: 51-61.4. ASH M. OSTI H E. R. HAYWARD, R.: Astudy of periodontalhazards of third molars.

Periodontol. 1962: 33: 209-219.


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40 KUGELBERG AHLSTRL>M ER IC SO N A ND H UG OS ON5. BJORN H. HOLMBERG K.: Radiographic

determination of periodontal bone destruc-tion in epidemiological research. Odontol.Revy 1966: 17: 232 250.6. COSTICH E. R.: The role of oral surgery inpreventive dentistry. Dent. Clin. North Am.1965: 19: 475--483.7. DENTAL CLINICS OF NORTH AMERICA The.July 1979: 23 no. 3.8. ELLEGARD B. LOE H.: New attachment ofperiodontal tissues after treatment of intra-bony lesions. J Periodontol. 1971: 42: 648-652.9. GROVES B. J. MOORE J. R. : The per io -dontal implications of flap. design in lowert hi rd molar extractions. Dent. Pract. Dent.Rec. 1970: 20: 297-304.10. GRONDAHL H. G. LEKHOLM U.: Influenceof mandibular third molars on related supporting tissues. Int. J Oral Surg. 1973: 2: 137-142.11. KARRING T. NYMAN S. LINDHE J.: Heal-ing following implantation of periodontitisaffected roots into bone tissue. J linPeriodontol. 1980: 7: 96-105.12. KILLEY H. C. KAY L. W : The impactedwisdom tooth. Churchill Livingstone Edin-burgh London and New York 1975.

13. KUGELBERG C. F. AHLSTROM U. ERICSONS. HUGOSON A.: Periodontal healing afterlower third molar surgery. Imprecision andinaccuracy in radiographic determination ofintrabony defects. In manuscript form.14. LISTGARTEN M. A.: Periodontal probing:what does i t mean? J Clin. Periodontol. 198 :7: 165 176.15. LISTGARTEN M. A. HELLDEN L.: Relativedistribution of bacteria at clinically healthyand periodontally diseased sites in humans. JClin. Periodontal. 1978: 5: 115-132.16. LISTGARTEN M. A. ROSENBERG M. M.:Histological study of repair following newattachment procedures in human periodontallesions. J Periodontal. 1979: 50: 333-344.17. LClE H. SILNESS J.: Periodontal disease inpregnancy. I. Prevalence and severity. ActaOdontol. Scand. 1963: 21: 533-551.18. MATTSSON 0.: A magnifying viewer forphotofluorographic films. Acta Radiol. 1953:39: 412 414.19. NATIONAL INSTITUTES OF HEALTH Consensusdevelopment conference for removal of thirdmolars. J Oral Surg 1980: 38: 235-236.

20. NIELSEN I. M. GLAVIND L. KARRING T.:Interproximal periodontal intrabony defects.J Clin. Periodontol. 1980: 7: 187-198.

21. NITZAN D. KEREN T. MARMARY Y.:Does an impacted tooth cause root resorptionof the adjacent one? Oral Surg. 1981: 51: 221-224.22. NYMAN S. LINDHE J. KARRING T.: Healing fol lowing surgical tr ea tmen t and rootdemineralization in monkeys with periodon-tal disease. J Clin. Periodontol. 1981: 8: 249-258.23. OSBORNE W. H. SNYDER A. J. TEMPEL T.R.: Attachment levels and crevicular depth atthe distal of mandibular second molars following removal of adjacent third molars. JPeriodontol. 1982: 53: 93 95.24. POLSON A. M HElJL L. C.: Osseous repairin infrabony periodontal defects. J Clin.Periodontal. 1978: 5: 13-23.25. ROSLING B.: Plaque control. A determiningfactor in the treatment periodontal disease.Thesis. Gothenburg Sweden 1976.

26. SILNESS J. LOE H.: Periodontal disease inpregnancy. Correlation between oralhygiene and per iodonta l condition. ActaOdontol. Scand. 1964: 22: 121-135.27. STAHL S. S.: Gingival repair potential. J OralMed. 1976: 31: 104--110.28. STEPHENS R. J.: A periodontal evaluation two types mucoperiosteal flaps used raccess in removing impacted third molars. MS. thesis. Columbus Ohio US A 1977.29. SZMYD L. HESTER W. R.: Crevicular depthof the second molar in impacted third molarsurgery. J Oral Surg. 1963: 21: 185-189.30. WOOLF R. H. MALMQUIST J. P. WRIGHTW. H.: Third molar extractions: periodontalimplication of two f lap designs. Gen. Dent.1978: 26: 52-56.31. ZIEGLER R. S.: P reven tive dentistry - newconcepts: preventing periodontal pockets. Va.Dent. J 1975: 52: 11-13.

Address:Carl F. KugelbergThe Institute for PostgraduateDental EducationBox 1030S 551 11 JiinkiipingSweden

kugelberg 1985 periodontal healing after exo wisdom

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