Bilaminar techniques for thetreatment of recession-typedefects. A comparativeclinical studyZucchelli G, Amore C, Sforza NM, Montebugnoli L, De Sanctis M: Bilaminartechniques for the treatment of recession-type defects. A comparative clinical study. JClin Periodontol 2003; 30: 862–870. r Blackwell Munksgaard, 2003.

AbstractObjectives: Complete root coverage is the primary objective to be accomplishedwhen treating gingival recessions in patients with aesthetic demands. Furthermore, inorder to satisfy patient demands fully, root coverage should be accomplished by softtissue, the thickness and colour of which should not be distinguishable from those ofadjacent soft tissue. The aim of the present split-mouth study was to compare thetreatment outcome of two surgical approaches of the bilaminar procedure in terms of(i) root coverage and (ii) aesthetic appearance of the surgically treated sites.

Material and Methods: Fifteen young systemically and periodontally healthysubjects with two recession-type defects of similar depth affecting contralateral teethin the aesthetic zone of the maxilla were enrolled in the study. All recessions fall intoMiller class I or II. Randomization for test and control treatment was performed bycoin toss immediately prior to surgery. All defects were treated with a bilaminarsurgical technique: differences between test and control sites resided in the size,thickness and positioning of the connective tissue graft. The clinical re-evaluation wasmade 1 year after surgery.

Results: The two bilaminar techniques resulted in a high percentage of root coverage(97.3% in the test and 94.7% in the control group) and complete root coverage(gingival margin at the cemento-enamel junction (CEJ)) (86.7% in the test and 80% inthe control teeth), with no statistically significant difference between them.Conversely, better aesthetic outcome and post-operative course were indicated by thepatients for test compared to control sites.

Conclusions: The proposed modification of the bilaminar technique improved theaesthetic outcome. The reduced size and minimal thickness of connective tissue graft,together with its positioning apical to the CEJ, facilitated graft coverage by means ofthe coronally advanced flap.

Key words: gingival recession; root coverage;pedicle flap; connective tissue graft; aesthetics

Accepted for publication 16 December 2002

Gingival recession can be defined as ashift of the gingival margin to a positionapical to the cemento-enamel junction(CEJ) with oral exposure of the rootsurface (Wennstrom 1994). The conse-quence of this is a clinical crownlengthening. The presence of gingivalrecessions at the anterior teeth mayrepresent an aesthetic problem for the

patient who complains about the ex-cessive length of some of his/her teeth.This disharmony may be apparent in thepatient’s smile or even at a functionallevel (phonics, chewing). More seldom,root exposure, due to gingival recession,may cause dentine hypersensitivity andconsequently patient discomfort and/orinadequate oral hygiene. The irregular

outline of the gingival margin, even inthe absence of tooth hypersensitivity,may render plaque control more diffi-cult for the patient, even more so whengingival recession is triangular shapedwith acute angles (the so-called ‘‘Still-man cleft’’).

The international literature has thor-oughly documented that gingival reces-

G. Zucchelli1, C. Amore1,N. M. Sforza1, L. Montebugnoli2

and M. De Sanctis1

Departments of 1Periodontology, 2Dental

Emergency, Bologna University, Bologna,

Italy

J Clin Periodontol 2003; 30: 862–870 Copyright r Blackwell Munksgaard 2003Printed in Denmark. All rights reserved

sion can be successfully treated usingseveral surgical procedures (Wennstrom1994), irrespective of the utilized tech-nique, provided the biologic conditionsfor accomplishing root coverage aresatisfied: no loss of interdental soft andhard tissues height (Miller 1985).

The selection of one surgical techni-que over another depends on severalfactors, some of which are related to thedefect (the size of the recession defect,the presence or absence of keratinizedtissue adjacent to the defect, the widthand height of the interdental soft tissue,the depth of the vestibulum or thepresence of frenuli) while others arerelated to the patient (Zucchelli & DeSanctis 2000). Furthermore, the clini-cian must consider data from theliterature in order to select the mostpredictable surgical approach amongthose feasible in a given clinical situa-tion.

In patients with aesthetic requests ifthere is adequate keratinized tissueapical or lateral to the recession defect,pedicle flap surgical techniques (coron-ally advanced or laterally moved flaps)are recommended (Grupe & Warren1956, Guinard & Caffesse 1978,Tenenbaum et al. 1980, Caffesse et al.1984, Allen & Miller 1989,Wennstrom& Zucchelli 1996). In these surgicalapproaches, the soft tissue utilized tocover root exposure is similar to thatoriginally present at the buccal aspect ofthe tooth with the recession defect, andthus the aesthetic result is satisfactory.Conversely, when the keratinized tissuelateral or apical to the gingival defect isnot adequate, free graft procedures haveto be performed (Sullivan & Atkins1968, Mlinek et al. 1973, Matter 1980,Holbrook & Ochsenbein 1983, Miller1985, Borghetti & Gardella 1990, Tol-mie et al. 1991). The use of a freegingival graft to treat recession defectsin patients with aesthetic requests is notrecommended because of the pooraesthetic outcome and the low rootcoverage predictability (Wennstrom1994). The use of a pedicle flap tocover the graft (bilaminar technique)improves the root coverage predictabil-ity (as it provides the graft with anadditional blood supply) and the aes-thetic result because it hides the white-scar colour of the graft and masks theirregular outline of the mucogingivaljunction that frequently results after afree graft procedure (Langer & Langer1985, Raetzke 1985, Nelson 1987,Harris 1992, Allen 1994, Bouchard

et al. 1994, Bruno 1994, Wennstrom &Zucchelli 1996).

The recent literature indicates thebilaminar techniques (i.e. partially dis-epithelized or connective tissue graftcovered by a pedicle flap) as highlypredictable root coverage surgical pro-cedures (Wennstrom 1994), even if thereported percentage of complete rootcoverage with the bilaminar proceduresranges from 42% (Raetzke 1985) to89% (Harris 1992).

During the last two decades, clini-cians have introduced several modifica-tions to the original bilaminar proceduredescribed by Raetzke (1985), resultingin more predictable outcomes, in termsof root coverage, and greater aestheticsatisfaction for the patients. Thesemodifications related both the type ofgraft (partially or completely disepithe-lized) harvested from the palate and thedesign (envelope-type or with vertical-releasing incision) of the covering flap.

Some authors used an envelope(Raetzke 1985, Allen 1994) or reposi-tioned flap (Langer & Langer 1985) tocover the epithelial-connective tissuegraft partially. Others utilized coronallyadvanced flaps with (Nelson 1987,Wennstrom & Zucchelli 1996) or with-out (Bruno 1994) vertical-releasing in-cisions, or laterally moved papillae flaps(Harris 1992) to cover connective tissuegrafts. In all the mentioned surgicalapproaches, the size of the graft ex-ceeded that of the bone dehiscence andit was positioned (and sutured) at thelevel of the CEJ.

Although root coverage became morepredictable, the aesthetic appearance ofthe surgically treated area was often incontrast with that of adjacent soft tissues.This was due to a number of reasons:

(a) the chromatic difference betweenthe uncovered epithelized portion ofthe graft and the adjacent softtissues (Langer & Langer 1985,Raetzke 1985, Allen 1994);

(b) the dischromy associated with thepartial exposure of connective tis-sue graft due to a dehiscence of thecovering flap (Nelson 1987, Bruno1994, Wennstrom & Zucchelli1996); and

(c) the difference in thickness between thegrafted area and adjacent soft tissues.

The aim of the present study was tocompare root coverage and aestheticresults of a modified surgical approachfor the bilaminar procedure with those

achieved with a more traditional bila-minar technique.

Material and Methods

Subject and site selection

The subject population consisted of 15young (age range 18–35 years) patientswith aesthetic problems due to theexposure of recession-type defects whensmiling. The participants were selectedon a consecutive basis among patientsconsulting the Department of Period-ontology, University of Bologna. Ascreening examination revealed that allsubjects showed a normal medicalhistory and none had loss of periodontalsupport at tooth surfaces other thanthose showing recession defects.

Each subject enrolled in the studypresented two recession-type defects, ofsimilar depth (the difference in reces-sion depth should be 42mm), affectinghomologous contralateral teeth in theupper jaw. Only teeth from #15 to #25were included in the study. All therecession defects fall into class I or IIaccording to the definitions given byMiller (1985), since no loss of inter-dental soft and hard tissue height waspresent. The experimental procedurewas performed using the split-mouthdesign. Randomization for test andcontrol treatment was performed bycoin toss immediately prior to surgery.All defects were treated with a bilami-nar surgical technique (connective tis-sue graft covered by a coronally adva-nced flap): differences between test andcontrol surgical approaches resided inthe size, thickness and positioning of theconnective tissue graft.

Following the screening examination,all subjects received a session ofprophylaxis, including instruction inproper oral hygiene measures, scalingand professional tooth cleaning with theuse of a rubber cup and a low abrasivepolishing paste. A coronally directedroll technique was prescribed for teethwith recession-type defects in order tominimize the toothbrushing trauma tothe gingival margin. Surgical treatmentof the recession defects was not sched-uled until the patient could demonstratean adequate standard of supragingivalplaque control.

Clinical characterization of patients andselected sites

Full mouth and local plaque scores(FMPS) were recorded as the percen-

Bilaminar techniques for the treatment of recession-type defects 863

tage of total surfaces (four aspects pertooth) that revealed the presence ofplaque (O’Leary et al. 1972). Bleedingon probing was assessed dichotomouslyat a force of 0.3N with a manualpressure-sensitive probe.n Full mouth(FMBS) and local bleeding score wererecorded as the percentage of totalsurfaces (four aspects per tooth) thatrevealed the presence of bleeding uponprobing.

The following clinical measurementswere taken at the facial aspect to theexperimental teeth 1 week before thesurgery and at 1-year follow-up:

– gingival recession depth (RECdepth), measured from the CEJ tothe most apical extension of thegingival margin;

– gingival recession width (RECwidth), measured at the level of theCEJ;

– probing pocket depth (PPD), mea-sured from the gingival margin to thebottom of the gingival sulcus;

– clinical attachment level (CAL), mea-sured from the CEJ to the bottom ofthe gingival sulcus;

– gingival height (GH), measured fromthe gingival margin to the muco-gingival line.

A single investigator performed theclinical measurements at baseline andafter 1 year. He was unaware of thetreatment assignment. All measure-ments were performed by means of amanual probe and were rounded up tothe nearest millimetre.

A questionnaire was given to eachpatient before surgery. It was dividedinto three parts to be completed by thepatient in different time periods:

– the first part, concerning the patient’smajor problem associated with thepresence of recession (excessivetooth length, contrast in colour orlack of gingiva), was completedbefore surgery;

– the second part, regarding the post-operative course, was completed atthe time of suture removal; and

– the third part, concerning the finalaesthetic outcome, was completed bythe patient at the 1-year follow-upvisit.

Furthermore, patients were asked toindicate if one technique was preferableto the other in terms of post-operativecourse and aesthetics.

In terms of post-operative course,patients were asked to select one of thefollowing choices: bad, bothersome,good, optimum. In the case of differ-ences in post-operative discomfort be-tween the test and control surgicalprocedures, the patient had to indicateif this was due to the healing of thebuccal area or to the palate wound.

In terms of aesthetic outcome, pa-tients were asked to express theiropinion about the appearance of thetreated teeth by selecting one of thefollowing choices: bad, sufficient, good,optimum aesthetics. In the case ofdifference in the aesthetic opinionbetween test and control teeth, patientswere asked to indicate the reason(s) for

this difference, selecting one or more ofthe following choices: difference intooth length, difference in colour blend-ing, difference in gingival thickness.

Surgical technique (Fig. 1)

Both test and control defects weretreated with the same design of thecovering flap that included:

– two horizontal incisions (extended3mm each in the mesial–distal direc-tion) performed at a distance from thevertex of the anatomic papilla equalto the depth of the recession; and

– two bevelled vertical-releasing inci-sions that extended into the alveolarmucosa.

A split-thickness flap was elevatedand all muscle insertions were elimi-

Fig. 1. Surgical technique adopted in the test site. (a) Pre-operative clinical view of the test-treated tooth: 4mm depth gingival recession with 1mm height of keratinized tissue is presentat tooth #23. (b) The connective tissue graft is sutured apical to the CEJ with double externalvertical mattress sutures. The graft covers the bone dehiscence up to the level of the bonecrest (see text for further details). (c) Suture of the covering flap (see text for more details).The flap completely covers the connective tissue graft. (d) The post-operative (1-year)clinical view shows the treated tooth with the same soft tissue margin originally presentapical to the recession defect, a good colour blending of the treated area and the increase ingingival thickness limited to the area of root exposure.

nPCP-UNC 15 probe tip, Hu Friedy, Chicago,

IL, USA, equipped with a Brodontic spring

device (Dentramar, Waalwijk, Holland).

864 Zucchelli et al.

nated in order to facilitate its coronaldisplacement. The root surface wasmechanically treated with the use ofcurettes. Only that portion of the rootsurface with loss of clinical attachment(gingival recession1probing pocketdepth) was instrumented. Root planingwas terminated when a clean and hardroot surface was obtained.

The connective tissue graft washarvested from the palate with the‘‘trap-door’’ approach described byHarris (1992) when the shape of thepalate and the thickness of the palatalsoft tissues permitted it. Otherwise, inthe presence of unfavourable palatalanatomic conditions, an epithelizedgraft was taken and it was subsequentlydisepithelized by means of a blade.

The mesio-distal length of the graftwas 6mm greater than the width of therecession measured at the level of theCEJ.

In the test sites, the apico-coronaldimension of the graft was equal to thedepth of the bone dehiscence (measuredfrom the CEJ to the most apicalextension of the buccal bone crest)minus the pre-operative height of kera-tinized tissue apical to the recessiondefect. The thickness of the graft,measured with an Iwannsson gaugew

(Baldi et al. 1999), was less than 1mm.The connective tissue graft was posi-tioned apical to the CEJ at a distanceequal to the height of keratinized tissueoriginally present apical to the recessiondefect (Fig. 1).

A double vertical mattress suture wasperformed to anchor the connectivetissue graft to adjacent buccal softtissue. This suture was started byperforating the buccal soft tissue me-sial/distal to the recession, and waspassed below the releasing incisionand through the graft, from the internalto the external surface. Then it wasbrought 1mm coronally on the externalaspect of the graft and passed againthrough the graft (from the external tothe internal aspect) and below thereleasing incision perforating (from theinternal to the external aspect) theadjacent buccal soft tissue 1mm coronalto the point where the suture wasstarted; here a surgical knot was per-formed to complete the suture (Fig. 1).

An identical suture was performed atthe other side of the recession defect(distal/mesial) to complete graft stabili-zation.

This positioning of the graft left themore coronal portion of the root ex-posure for coverage by the gingivaltissue originally present apical to therecession defect, which will then be-come the gingival margin of the treatedtooth (Fig. 1).

In the control tooth, the apico-coronal length of the graft was 3mmgreater than the depth of the bonedehiscence and the thickness of thegraft was greater than 1mm.

The graft was positioned at the levelof the CEJ and anchored at the base ofthe anatomic papillae with two inter-rupted sutures.

The remaining buccal soft tissue ofthe anatomic interdental papillae wasdisepithelized to create connective tis-sue beds to which the surgical papillaeof the covering flap were sutured.

The suture of the covering flap startedwith two interrupted sutures performedin the most apical extension of themesial- and distal-releasing incisions,and then it proceeded coronally, withother interrupted sutures, each of themdirected, from the flap to the adjacentbuccal soft tissue, in the apical–coronaldirection. After these sutures, the mostmarginal portion of the covering flapwas stable in its coronal position with-out disrupting forces acting on it at thetime of the final suture. This last suturewas a sling suture. It started perforatingthe distal surgical papilla (from theexternal to the internal) and the corre-sponding disepithelized anatomic papil-la reaching the palate side, and then itwas brought mesially, and buccallypassing below the mesial contact point(without perforating the mesial inter-dental papilla). Then the mesial surgicaland anatomical papilla were perforated(from the external to the internal) and,once in the palatal side, the suture wasbrought distally and buccally passingbelow the distal contact point, where itwas closed with a surgical knot (Fig. 1).

This sling suture was performed topermit a precise adaptation of the buccalflap on the underlying connective tissuegraft and to stabilize every singlesurgical papilla over the interdentalconnective tissue bed.

Post-surgical infection control

Patients were instructed not to brushtheir teeth in the treated area, but torinse their mouth with chlorhexidinesolution (0.12%) twice daily for 1min.

Fourteen days after the surgicaltreatment, the sutures were removed.Plaque control in the surgically treatedarea was maintained by chlorhexidinerinsings for an additional 2 weeks. Afterthis period, the patients were againinstructed in mechanical tooth cleaningof the treated tooth region using a softtoothbrush and a roll technique. Allpatients were recalled for prophylaxis 1,3 and 5 weeks after suture removal and,subsequently, once every 3 months untilthe final examination (12 months).

Covering flap dehiscence

The dehiscence of the covering flap(FD), measured from the level of theCEJ to the most coronal extension of theflap covering the graft, was evaluatedevery 15 days during the first monthafter surgery and every single month forthe remaining experimental period (11months).

Data analysis

Statistical Application Softwarez wasused for the statistical analysis.

– Paired Student’s t-test was applied tocompare test and control groups interms of REC depth, CAL, PPD, GHvalues at baseline and the thicknessand length of the connective tissuegraft harvested from the palate at thetime of surgery.

– General linear models were fitted andmultiple regression ANOVA for re-peated measures with split-plot de-sign was used to evaluate theexistence of any significant differenceas regards CAL, REC depth, PPD,GH and FD between the two techni-ques, time (1-year data as comparedto data at baseline). In the case ofsignificance, Bonferroni t-test wasapplied as a multiple comparison test.

– General linear models were also fittedrelating 1-year % root coverage and1-year CAL gain to one categorical(technique) and four continuous (GH,PPD, REC depth, REC width) factorsas covariates (ANCOVA).

– w2 analysis was used to evaluate thedifferences between techniques withrespect to % of complete root cover-age and to evaluate the techniquepreferred by the patient, and thesubjective factors responsible for thedifference between procedures.

wHu-Friedy, Chicago, IL, USA. zSAS, version 6.09, SAS Institute, Cary, NC.

Bilaminar techniques for the treatment of recession-type defects 865

– The Wilcoxon signed-rank test wasused to evaluate any significantdifference between techniques inscores from the questionnaire assess-ment concerning subjective experi-ences in terms of post-operativediscomfort/pain and final aestheticoutcome.

Results

Following the initial oral hygiene phaseas well as at the post-treatment exam-inations, all subjects showed low fre-quencies of plaque harbouring toothsurfaces (FMPS o20%) and bleedinggingival units (FMBS o15%), indicat-ing a good standard of supragingivalplaque control during the study period.

Baseline defect characteristics

Baseline defect characteristics (meanvalues7SD) are shown in Table 1.

No statistically significant differencewas observed among the two matchedexperimental groups in any of theconsidered clinical parameters, indicat-ing that the randomization process hadbeen effective.

All patients enrolled in the studyindicated tooth length as the cause ofthe aesthetic problem associated withthe recession defect. Two of them alsoindicated the lack of gingiva, whilenone mentioned the difference in colouras a significant unaesthetic factor.

In the test group, the mean thicknessof the graft was 0.770.38mm while themean height (apical–coronal dimension)was 4.971.22mm. All grafts wereharvested by means of the ‘‘trap-doorapproach’’ and primary intention palatewound healing was accomplished in alltreated cases. At the 15-day controlvisit, no signs of primary palatal flapdehiscence or necrosis were demon-strated.

In the control group, the meanthickness of the graft was 1.470.52mm while the mean height was9.672.11mm. In this group, the ‘‘trap-door’’ approach was used in nine

patients, while in the remaining six anepithelized graft was taken from thepalate. Thereafter, complete closure ofthe palatal wound was accomplishedonly in nine patients. In three of them, anecrosis of the primary palatal flapoccurred during the first healing period(15 days).

1-year clinical outcome

REC depth: A significant ( po0.01)REC decrease was observed in boththe groups (from 4.070.76 to0.170.31mm at test sites and from3.970.80 to 0.370.62mm at controls),with a similar ( p5NS) decreasing ratefor both groups of teeth. This change inrecession depth corresponded to a rootcoverage of 97.377.01% and 94.7711.21% in the test and control group,respectively.

Complete root coverage (up to theCEJ) was accomplished in 86.7% (13out of 15 of the treated cases) in the testgroup and in 80% (12 out of 15) in thecontrol group (w25 0.24; NS).

The significance of factors affecting 1-year % root coverage was evaluated byfitting a general linear model (Table 2).

The variables significantly affectingthe % root coverage was the REC depthat baseline (F5 17.36; po0.01) andGH at baseline (F5 27.49; po0.01):the % root coverage increased withincreasing initial recession depth andincreasing gingival height.

No significant effect was found withregard to the type of technique used(F5 0.31; NS).

CAL: No significant difference be-tween the groups was found at baselineand a significant (po0.01) CAL de-crease (CAL gain) in both groups ofteeth was found (from 5.170.80 to1.170.31mm at test sites and from5.070.76 to 1.970.52mm at controls).This change in CAL corresponded to aCAL gain of 3.970.70 and 3.170.74 inthe test and control group, respectively( po0.01).

Analogous results were found withrespect to PPD and GH. In particular,PPD remained shallow in both groupsalthough a significantly greater increase( po0.01) was demonstrated in thecontrol than the test group. Similarly,the average increase in GH was statis-tically significant for both groups, butgreater in the control group.

Changes in clinical parameters at 1year are summarized in Table 3.

Flap dehiscence: Statistical analysisshowed a significant relationship be-tween techniques (F5 79.7; po0.01);in particular, in control sites, coveringflap dehiscence occurred in eight out of15 control sites and, in six of them, wasalready clinically present at the 15-dayvisit (at the time of suture removal). Asshown in Fig. 2, the amount of flapdehiscence increased during the follow-ing 15 and 30 days, after which itremained stable for the entire durationof the study. In the eight teeth thatexperienced dehiscence of the coveringflap, root exposure occurred only inthree cases, while in five teeth theexposed graft remained at the level ofthe CEJ covering the gingival recession.

On the other hand, in the test sites,covering flap dehiscence occurred inonly two teeth, and in both cases it wasassociated with root exposure. Graftexposure was never demonstrated.

Post-operative course: Patients re-ported a significantly (Wilcoxon signed-rank test; po0.01) better post-operativecourse in the test group (average score3.170.35 with an average rank of 19.1),with respect to the control group(average score 2.670.51 with an aver-age rank of 11.9). Seven patientsindicated a greater discomfort in thecontrol sites as compared with the testsites, while the remaining eight did notreport any difference between sites(w25 14.0; po0.01). All seven patientsindicating a greater discomfort in thecontrol sites referred a more painful

Table 1. Clinical parameters at baseline (MV7SD) (significance was obtained from pairedStudent’s t-test)

Test group Control group t p

REC depth 4.070.76 3.970.80 0.25 NSCAL 5.170.80 5.070.76 0.29 NSPPD 1.170.26 1.170.35 0.56 NSGH 1.170.26 1.270.41 1.46 NS

Table 2. Results by fitting a general linearmodel relating 1-year % root coverage to onecategorical variable (technique) and fourcontinuous (GH, PPD, REC depth and RECwidth) factors as covariates (ANCOVA)

Source F-ratio p-Value

GH basal 27.49 o.01PPD basal 0.78 NSREC depth basal 17.36 o.01REC width basal 2.64 NSTechnique 0.31 NS

866 Zucchelli et al.

palate wound healing as the cause(w25 12.0; po0.01).

Aesthetic outcome: Patients weremore satisfied (Wilcoxon signed-ranktest; po0.01) with the appearance ofthe test-treated areas (average score 3.570.51 with an average rank of 21.1)with respect to the control sites (averagescore 2.570.63 with an average rank of9.9). In particular, in the test group,eight subjects out of 15 reported anoptimum aesthetic result and the re-maining seven a good result, while, inthe control group, eight subjects re-ported a good aesthetic outcome, sixwere not completely satisfied and one

indicated an absolutely unsatisfactoryaesthetic result. When asked about thepreferred procedure, 12 patients re-ported better aesthetics of the test-compared with control-treated sites(w25 24.0; po0.01). Nine of themindicated the excessive thickness ofthe control-treated areas as one of thereasons for the worst result (in fourpatients the excessive thickness was theonly negative factor). The poor colourblending was indicated by eight pa-tients, while only one patient indicatedexcessive tooth length as one of thereasons (together with the excessivethickness and poor colour blending)

for the worst aesthetic results in thecontrol sites.

Discussion

The goal of the present study was tocompare two surgical approaches of thebilaminar procedure in terms of (1) rootcoverage outcomes and (2) aestheticappearance of the surgically treatedsites.

In order to have a precise method ofevaluating the differences between thetwo techniques, considerable effort wastaken to identify test and control sites assimilarly as possible in the upper jaw ofthe same mouth. The selection of thegingival lesion was therefore very strictand justifies the relatively small numberof patients included in the study.

Present data indicate that the twosurgical approaches adopted in the studywere highly effective and predictable inobtaining root coverage of gingivalrecessions. In fact, both techniquesresulted in a very high percentage ofroot coverage (97.3% in the test groupand 94.7% in the control group) andcomplete soft tissue root coverage (upto the CEJ) was accomplished in thegreat majority of test- (86.7%) andcontrol-treated (80%) cases. No clinicaland statistical differences were demon-strated in root coverage outcomes be-tween the two surgical approachesadopted in the present study. This rateof successful outcomes of the treatmentis similar or even somewhat higher thanthat previously reported in the literaturefor the bilaminar techniques (Harris1992,Allen 1994, Wennstrom & Zuc-chelli 1996) and for other root coverageprocedures (Wennstrom 1994).

The regression model, adopted in thepresent study, indicated that the % ofroot coverage was positively affected byinitial recession depth and gingivalheight. These data indicate that betterroot coverage outcome can be achievedin recession defect with deeper rootexposure and with higher gingival tissueapical to the defect. The efficacy ofbilaminar techniques in the treatment ofdeep recession has already been demon-strated in the literature (Zucchelli et al.1998), while it can be speculated thatthe presence of high gingival tissueapical to the defect may have facilitatedcovering flap management and suturingtechnique, while maximizing the possi-bility to achieve and maintain completecoverage of the underlying connective

Table 3. Clinical change at 1 year (MV7SD) (significance was obtained from paired Student’st-test)

Test group Control group t p

Root coverage 3.970.71 3.670.72 1.73 NSCAL gain 3.970.70 3.170.74 4.58 o.01PPD increase 0.170.25 0.570.51 3.23 o.01GH increase 2.370.59 3.370.72 5.17 o.01

Interactions and 95.0 % Bonferroni intervals

F D

testcontrol

NS NS NS NS

NS NS

**

****

-0.4

0

0.4

0.8

1.2

1.6

15 gg 30 gg 60 g 180 gg 360 gg

*

mm

Fig. 2. Time-related variations in FD in both test and control groups; npo0.01.

Fig. 3. Pre- (a) and post- (b) operative clinical images of the controlateral control-treatedtooth. Complete root coverage has been achieved. The 1-year clinical view shows theunaesthetic white-scar appearance of the grafted area due to dehiscence of the covering flap.It can be speculated that the size and thickness of the graft and its excessive coronalplacement might have reduced the vascular exchange between the covering flap and theunderlying receiving connective tissue bed, causing the complete recession of the flap.Furthermore, the increase in gingival thickness extends beyond the area of root exposure.

Bilaminar techniques for the treatment of recession-type defects 867

tissue graft. This may have contributedto reducing the risk of flap dehiscenceand thus participated in improving theroot coverage outcome of the bilaminartechnique.

Both techniques, adopted in thepresent study, resulted in a clinicallyand statistically highly significant clin-ical attachment gain (statistically great-er in the test-treated teeth) with nosignificant changes in the depth of theprobing buccal pocket depth. Further-more, a clinically significant increase inthe width of keratinized tissue wasdemonstrated after both the adoptedsurgical procedures. This increase wasstatistically greater in the control-trea-ted teeth.

Data resulting from the questionnaireof the present study indicated that: (i)patients with aesthetic demands usuallycomplain about the excessive length ofthe tooth with gingival recession; (ii)once root coverage has been achieved,other factors like gingival thickness andcolour blending become important inpatient evaluation of the aesthetic out-come of a root coverage surgicalprocedure; and (iii) the type (primaryor secondary) of palatal wound healinggreatly influences the patient’s post-operative course.

The reduced thickness and apical–coronal dimension of the graft, togetherwith its positioning apical to the CEJ,were the most significant differencesbetween the two surgical techniquesadopted in the present study. Thesemodifications were primarily made toimprove the aesthetic outcome of thebilaminar procedure. The reduced thick-ness and height of the graft allowed oneto minimize the obstacle hindering theblood supply from the receiving con-nective tissue bed to the covering flap.During the first healing phase, in fact,the connective tissue graft represents anobstacle to the nutritional exchangesbetween the periosteal beds lateral andapical to the bone dehiscence and thecoronally advanced covering flap. Thebigger and thicker the graft, the greaterthe obstacle and the greater the risk ofcovering flap dehiscence and conse-quently graft exposure. This is con-firmed by the present data, whichindicated a high percentage (53%) offlap dehiscence in the control group,while no graft exposure was observed inthe test-treated teeth. When the con-nective tissue graft is exposed, it rapidlybecomes covered by a keratinizedepithelium and its colour becomes

similar to that of the patient’s palate.The consequence of this is a poor colourblending of the treated area with respectto the adjacent soft tissues. The im-portance of gingival colour in terms ofpost-operative aesthetics was demon-strated in the present study by thefact that covering the root exposurewith gingival tissues of different coloursfrom that of adjacent soft tissues did notsatisfy the patient’s aesthetic demands.In the present patient population, sixpatients were not satisfied with theaesthetic appearance of the control-treated sites, despite the complete rootcoverage that had been achievedand this was due to poor colour blend-ing of the surgically treated area. Inorder to satisfy the patient’s requestfully, recession defects should be com-pletely (up to the CEJ) covered withgingival tissues, the colour and thick-ness of which should not be distinguish-able from those of adjacent soft tissues.The reduced dimensions of the graftmay improve the aesthetic outcome alsoby minimizing the increase in gingivalthickness at the surgically treated site.When the connective tissue graft isextended beyond the buccal bone crest,as was performed in the control group ofthe present study, it may cause anexcessive soft tissue thickness in closeproximity to the fornix (especially in apatient with a small vestibulum). Thisincreased thickness may not only alterthe aesthetic harmony of mucogingivaltissues but may also be the cause offood accumulation that can prove to bevery unpleasant for the patient. Thenegative impact of the excessive softtissue thickness on the patient’s evalua-tion of the aesthetic appearance ofthe surgically treated area has beendemonstrated in the present study: 10patients complained about the excessivethickness of the control sites and towhich they attributed one of the reasonsfor the worst aesthetic outcome ofthe control compared to test-treatedteeth.

The increase in the soft tissue thick-ness consequent to the use of a con-nective tissue graft should be limited tothe area previously occupied by the rootexposure. Therefore, the thickness ofthe connective tissue graft should bechanged according to the presence andthe amount of root structure loss (caries,abrasions) associated with the gingivalrecession. In the presence of deepabrasion, a thicker graft should be usedto compensate the loss of hard tissue

and to provide the treated tooth with acorrect emergence profile.

The positioning of the graft apical tothe CEJ further contributed to improv-ing the aesthetic outcome after thebilaminar procedure. Firstly, it allowedthe most coronal portion of the root(close to the CEJ) available for thegingival tissue originally present apicalto the recession defect. Therefore, thechromatic characteristics and the thick-ness of the gingival margin, originallypresent apical to the root exposure, thatwill become the marginal tissue of thetreated tooth, are not modified and thusresult in being indistinguishable fromthose of adjacent teeth. Secondly, theapical positioning of the graft allowedfor the increase of the vascular arealateral to the root exposure, thus redu-cing the risk of covering flap dehiscenceand unaesthetic graft exposure .

The use of thin suture (6-0) togetherwith the utilization of a graft-suturingtechnique that displaced the surgicalknot out of the surgical area andminimized the amount of suture inter-posed between the graft and the cover-ing flap, may have contributed toreducing the risk of flap dehiscenceand thus participated in improving theaesthetic outcome of the bilaminarprocedure.

The surgical approach utilized in thetest sites of the present study caused lesspost-operative discomfort/pain than themore traditional bilaminar techniqueadopted in the control sites. Sevenpatients, in fact, reported greater dis-comfort in the control sites and this wasdue to the palate wound. A possibleexplanation for this difference was that,in all test sites, the reduced apico-coronal dimension and minimal thick-ness of the graft permitted the use of the‘‘trap-door approach’’ to harvest theconnective tissue grafts, and thus al-lowed for a primary intention palatalwound healing that was less traumaticfor the patients. Conversely, in six ofthe control cases the greater height andthickness of the graft obliged theclinician to take an epithelized graftfrom the palate and this caused a morepainful secondary intention palatalwound healing.

Conclusions

The results of the present study demon-strated that the proposed approach ofthe bilaminar technique was a veryeffective procedure for the treatment

868 Zucchelli et al.

of isolated gingival recessions in pa-tients with aesthetic demands since itresulted in complete soft tissue rootcoverage in the great majority of treatedcases. No significant differences weredemonstrated in terms of root coveragebetween the two procedures adopted inthe study. Conversely, better results interms of aesthetic outcome and post-operative course were indicated by thepatients in sites treated with the novelapproach compared to sites treated with amore conventional bilaminar technique.

The reduced thickness and apico-coronal dimension of the connectivetissue graft, together with its positioningapical to the CEJ, facilitated the graftcoverage by the coronally advanced flapand improved the aesthetic outcome. Infact, if the covering flap remained stablein the coronal position it was able tohide the unaesthetic white-scar appear-ance of the graft and to provide thetreated tooth with the same gingivalmargin originally present apical to therecession defect. The proposed surgicalapproach permitted the association ofthe aesthetic advantages of the coron-ally advanced flap to the increase in softtissue thickness and gingival heightconsequent to the use of free graftsurgical techniques.

Zusammenfassung

Zweischichtige Techniken fur die Behandlung

von Rezessionsdefekten. Eine vergleichende

klinische Studie

Hintergrund: Die vollstandige Deckung der

Wurzeloberflache ist das primare Ziel, das bei

der Therapie von fazialen Rezessionen bei

Patienten mit asthetischen Anspruchen erreicht

werden soll. Weiterhin sollte die Rezessions-

deckung, wenn sie den Anspruchen des Patient-

en vollends entsprechen soll, mit einer Dicke

und Farbe der Gingiva erreicht werden, die

nicht vom benachbarten Gewebe zu unterschei-

den sind.

Zielsetzung: Vergleich der Therapieergebnisse

von 2 chirurgischen Varianten der zweischich-

tigen Technik im Halbseitenversuch hinsich-

tlich (1) Rezessionsdeckung und (2)

asthetischer Erscheinung der chirurgisch behan-

delten Stellen.

Material und Methoden: 15 junge und par-

odontal gesunde Personen mit jeweils 2 Re-

zessionsdefekten ahnlicher Gro�e an

kontralateralen Zahnen im asthetischen Bereich

des Oberkiefers wurden in die Studie aufgen-

ommen. Alle Rezessionen gehorten in die

Miller-Klassen I oder II. Die Randomisierung

fur die Test- und Kontrollbehandlung erfolgte

unmittelbar praoperativ durch Munzwurf. Alle

Defekte wurden nach einer zweischichtigen

chirurgischen Technik behandelt: Die Un-

terschiede zwischen Test- und Kontrollstellen

bestanden in Gro�e, Dicke und Positionierung

des Bindegewebstransplantates. Die klinische

Nachuntersuchung erfolgte 1 Jahr postoperativ.

Ergebnisse: Beide zweischichtigen Techniken

fuhrten zu einem hohen Prozentsatz von

Wurzeldeckung (Test: 97,3%; Kontrolle:

94,7%) und kompletter Wurzeldeckung (Gingi-

varand an der Schmelz-Zement-Grenze [SZG])

(Test: 86,7%; Kontrolle: 80%) ohne statistisch

signifikante Unterschiede zwischen beiden

Gruppen. Allerdings wurden mit der Testther-

apie bessere asthetische Ergebnisse erzielt als

mit der Kontrollbehandlung.

Schlussfolgerung: Die vorgestellte Modifika-

tion der zweischichtigen Technik verbesserte

die asthetischen Ergebnisse. Die reduzierte

Gro�e und minimale Dicke des Bindegeweb-

stransplantates zusammen mit seiner Positio-

nierung apikal der SZG erleichterten eine

Deckung mittels eines koronalen Verschiebe-

lappens.

Resume

Techniques bilaminaires pour le traitement des

recessions. Une etude clinique comparative.

Objectif: Un recouvrement complet de la

racine est le premier objectif lorsque l’on traite

des recessions gingivales chez les patients ayant

une demande esthetique. De plus, afin de

satisfaire totalement la demande du patient,

cette couverture radiculaire doit aussi etre

realise par des tissus mous de couleur et

d’epaisseur qui ne se distinguent pas des tissus

mous adjacents. Le but de cette etude en bouche

separee etait de comparer le devenir de deux

approches chirurgicales de la technique bilami-

naire pour (i) le recouvrement de la racine et (ii)

l’apparence esthetique des sites traites chirurgi-

calement.

Materiel et Methodes: 15 sujets jeunes et

indemnes de maladie parodontale et systemique

presentant deux recessions de profondeur simi-

laires sur des dents contralaterales dans des

zones esthetiques du maxillaire furent enrolles

dans cette etude. Toutes les recessions etaient

des classes I ou II de Miller. La repartition pour

les traitements test ou controle fut tiree a pile ou

face juste avant la chirurgie. Toutes les lesions

furent traitees par la technique bilaminaire, la

difference entre les groupes residant dans la

taille, l’epaisseur et le positionnement du

greffon de tissus conjonctif. La reevaluation

clinique fut faite un an apres la chirurgie.

Resultats: Les deux techniques bilaminaires

ont entraine un fort pourcentage de recouvre-

ment radiculaire (97.3% pour le groupe test et

94.7% pour le groupe controle) et le recouvre-

ment complet (gencive marginale au niveau de

la CEJ) (86.7% dans le groupe test et 80% pour

le groupe controle) sans difference statistique-

ment significative entre elles. Par contre, un

meilleur rendu esthetique et suites post oper-

atoires furent rapportes par les patients pour le

traitement test.

Conclusions: La modification proposee de cette

technique bilaminaire ameliore le devenir

esthetique. La taille reduite et l’epaisseur mini-

male greffon conjonctif et son positionnement

apical au CEJ, ont facilite le recouvrement du

greffon par le lambeau deplace coronairement.

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Address:

G Zucchelli

Department of Periodontology

Bologna University

Via S. Vitale 59 40125

Bologna

Italy

Tel: +39 051 278011

Fax: +39 051 275208

E-mail: giovanni.zuchelli@unibo.it

870 Zucchelli et al.