International Journal of Paediatric Dentistry 1991; 1: 137-141
Gingival health associated with porcelain veneers on maxillary incisors J. S . R E I D ' , D . F. K I N A N E * & E. A D O N O G I A N A K 1 2 'Department of Conservative Dentistry, Glasgow Dental Hospital and School =Department of Periodontology, Glasgow Dental Hospital and School
Summary: The possible detrimental effect of acid-etched resin-bonded prostheses
and porcelain veneers on plaque accumulation and gingival health is currently disputed. Some workers recommend no tooth preparation prior to veneeringwhilst others recommend tooth preparation to prevent adverse gingival soft tissue reactions. In order to test the possible gingivaleffects of veneers placed without tooth preparation, this study was set up to compare gingival health on veneered and nonveneered maxillary incisors within the same individual during periods of normal tooth cleaning and of no tooth cleaning. No significant differences were noted in plaque or gingival indices, or in gingival crevicular fluid volume, between the 72 veneered and non-veneered sites during either study period. The results ofthis study suggest that placing porcelain veneers on unprepared teeth does not increase the risk of gingivitis.
Introduction There is some controversy about the effect of acidetched resin-bonded prostheses and porcelain veneers on plaque accumulation and gingivitis. Tooth preparation has been recommended before veneering to prevent overcontouring, as any increase in bulk may predispose to gingivitis [ 1-61. Other workers have recommended no tooth preparation and have found no adverse soft tissue reaction to prostheses or veneers [7- lo]. This study was designed to determine the effect on gingival health of acid-etched resin-bonded porcelain veneers cemented to unprepared labial surfaces of maxillary incisors, and to assess these effects during periods of normal tooth cleaning and of no tooth cleaning.
Methods Six dental students ( 5 male, 1 female) volunteered to take part in the study. They had no evidence Correspondenceto: Dr J. S. Reid, Department of Conservative Dentistry, Glasgow Dental Hospital and School, 378 Sauchiehall Street, Glasgow G2 352, UK.
of periodontal disease and no relevant medical histories. All the subjects (age range 20-2 1 years) had more than 26 teeth, a high standard of oral hygiene and healthy gingival tissues, with no pocketing greater than 3 mm. Fully informed consent was given by the volunteers, who were interviewed prior to commencing this study by the chairman and members of the local ethical committee.
Clinical procedures For each subject, a permanent maxillary central and adjacent lateral incisor were chosen to be veneered and the contralaterai teeth served as controls. All these teeth were sound, unrestored and vital. At the subject's first visit, alginate impressions were taken in stock trays and from the casts obtained an upper tray was constructed. The occlusion was checked for any occlusal interference and an occlusal registration was recorded using wax. At the second visit a master impression was recorded using an elastometric impression material (Provil M, Bayer, UK). Gingival tissues were not retracted. Tooth shade was recorded 137
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using a porcelain shade guide (Vita-Lumin, Germany). No tooth preparation was undertaken. The laboratory technician was instructed to construct two porcelain veneers as one unit joined at their approximal surfaces, to finish the veneers in a feather edge 1 mm supragingivally, and to add incisal cleats; the cleats acted as incisal stops to ensure the correct supragingival positioning of the gingival margin of the veeners. The teeth to be veneered were cleaned and isolated with rubber dam. The technique of acidetching and bonding the veneers to enamel has already been well described and is a standard technique [ 1 11. A light-cured enamel bonding agent was used (Scotchbond, 3M Healthcare). The veneers were finished using fine-fluted tungsten carbide burs and diamond polishing paste. The porcelain incisal cleats were removed using a highspeed water-cooled turbine. At the end of the study the porcelain veneers were removed.
Clinical assessments Plaque accumulation and gingival health were assessed and gingival crevicular fluid volumes were measured. All the data were collected by one of the authors (EA).
Plaque index. Plaque accumulation was assessed using the Plaque Index (PI) of Silness & Loe ( 1 964) [12], which is based on scoring the amount of plaque on the four tooth surfaces (approximal, lingual and labial) on a scale of 0-3. The lingual surface was not scored in the present study. Gingival index.The Lobene Index [ 131 scores the gingival condition of marginal and approximal tissues separately on a scale of 0-4. This index, termed the Modified Gingival Index (MGI), was calculated by examining the same sites as for the PI. Gingival crevicularfluid volume. Gingival crevicular fluid (GCF) volume was measured non-invasively from the veneer and control regions. During inflammation the volume of fluid increases in proportion with the degree of gingival inflammation, and direct volumetric GCF measurements can be used as a sensitive index of inflammation 1141.
Whatman grade 4 paper strips were used for the collection of GCF. Strips (2 x 13 mm2) were cut manually using a steel ruler and a scalpel, as recommended by previous investigators [ 151. A line was drawn 8 mm from the end of each strip, indicating the length of the paper to be inserted in the measuring instrument (Periotron 6000, Harco Electronics, Canada). Each crevicular site was carefully isolated with cotton rolls so that no saliva contamination of the samples occurred. Supragingival plaque was removed and the area was gently air-dried for 5 seconds and then left for 25 seconds prior to sampling. The paper strip was inserted into the crevice until mild resistance was felt, and was left there for 30 seconds. Care was taken to avoid mechanical injury of the tissues. After the collection of the GCF, the paper strip was transferred to the chairside-located ‘Periotron’ for quantification of the volume collected. Before commencing the study, a calibration graph was constructed for the Periotron 6000 in order to transform the digital readings from the filter strips into volumes and also to assess the accuracy of the instrument. Known volumes of serum diluted 1: 1 in phosphate-buffered saline were delivered to Whatman grade 4 paper strips with a Hamilton microsyringe in volumes ranging from 0.2 to 1 pl, in 0.2 pl increments. Each measurement was performed six times and the mean value for each volume was used in a linear regression analysis from which the slope and intercept were used to determine the volumes of crevicular fluid collected.
Statistical analysis Since each of the six subjects had two veneered teeth, data on PI, MGI and GCF were obtained from six veneer and six control sites in each patient (mesiolabial, mid-labial and distolabial), a total of 36 veneer and 36 control sites. Data from paired sites were compared using the nonparametric Wilcoxon signed rank test.
Study design To study the effect of the veneers during a period of no tooth cleaning, the human experimental gingivitis model introduced by Loe et al. (1965) [ 161 was used. This showed that cessation of oral
Porcelain veneers on maxillary incisors hygiene procedures by subjects with healthy gingivae leads to increased accumulation of bacterial plaque and subsequent development of gingival inflammation, which is completely reversible and resolves on re-institution of toothbrushing. This technique has been widely used [17] and has provided valuable information on the aetiology of periodontal disease. The study procedure was as follows:Day 0. Subjects were fitted with two maxillary anterior acid-etched resin-bonded porcelain veneers. Days 1-1 0: normal tooth cleaningperiod. Plaque and gingival scores were assessed every 3 days. The subjects employed their own normal oral hygiene procedures during this period. Days 11-13: rest period. Subjects were given a professional prophylaxis and three days later ceased cleaning their teeth. Days 14-35: no tooth cleaning period. Plaque, gingival and GCF scores were assessed every 3-4 days. Days 36-49. The subjects were given a thorough professional prophylaxis and instructed to recommence their normal oral hygiene procedures. PI and GI were assessed and GCF volumes determined after four days, one and two weeks. Day 49. The veneers were removed and the subjects recommenced oral’hygiene procedures.
Results Plaque and gingival indices are shown in Table 1. The plaque and gingival indices remained low or decreased during the 10-day normal oral hygiene period, rose steadily after oral hygiene was suspended at day 14, both indices peaking at day 35, and then fell after oral hygiene was reinstituted. The differences between veneered and control teeth for both plaque and gingival indices were not significant (for all paired analyses P>0.05). Although the data may suggest that there was a slower recovery to gingival health on veneered teeth, the differences were not statistically significant. Table 2 shows that GCF volume increased during the no-tooth-cleaningperiod and decreased when gingival health recovered. The differencesin mean GCF volume between veneered and control teeth were not significant.
Discussion An early report of the clinical use of porcelain veneers applied to unprepared teeth highlighted the benefits to those patients who did not want their teeth prepared [ 181. The introduction of the acid-etch technique [ 191allowed restorations to be bonded to enamel on a long-term basis. Initial
Table 1. Plaque and gingival indices during periods of normal toothcleaning (days 1-10), of no toothcleaning (days 14-35), and after resumption of toothcleaning (days 36-49). Mean scores ( fSD) of 36 veneer and 36 control sites (six of each in each of 6 subjects). Plaque index Day 1 4 7 14 18 21 25 28 31 35 39 42 49
139
Gingival index
Veneer sites mean fSD
Control sites mean fSD
Veneer sites mean f SD
Control sites mean fSD
0.50f0.14 0.28k0.45 0.35f0.13 0.41 k0.02 1.32k0.07 1.73f0.1 1 1.92f0.07 2.00k0.10 1.99 f 0 . 1 2 2.36f0.10 0.44f0.06 0.13f0.07 0.27f0.14
0.28 k 0.05 0.31 fO.10 0.18 f0.06 0.30f 0.18 1.43f0.5 5 1.54k0.07 1.96f 0.05 2.22f 0.07 2.4 1 f0.34 2.40 f 0.04 0.24 k 0.08 0. I9 k 0.06 0.33 f0.09
0.56 k 0.12 0.19 k0.06 0.39 f0.06 0.22 k 0.05 0.82 f0.13 1.31 20.03 1.93 f0.06 2.3 1 f 0.09 2.79 f 0.02 3.09 f0.12 1.98 f 0.03 1.07 & 0.18 0.73 f 0.1 4
0.37 f0.12 0.70 f0.08 0.35 f0.13 0.38 f0-06 1.04k0.19 1.45f0.22 2.1920.02 2.5 1 f 0.09 2.88 f 0.04 2.97 f 0.06 2.4 1 f 0.09 1.48 f 0.1 1 1.25f0.22
140
J. S. Reid et al.
Table 2. Gingival crevicular fluid volumes @I) during a period of no toothcleaning (days 14-35) and after resumption of toothcleaning (days 36-49). Mean values ( fSD) of 36 veneer and 36 control sites (six of each in each of six subjects).
Day
Veneer sites mean k SD
Control sites mean k SD
14 18 21 25 28 31 35 39 42 49
0.05 f0.04 0.12 f0.07 0.20 f0.13 0.13 k 0.03 0.14 f0.06 0.20 k 0.08 0.16 f0.07 0.09 f0.05 0.10 f0.05 0.07 f0.05
0.06 f0.05 0.19 k 0.03 0.1 5 f0.08 0.19 a0.12 0.17f 0.03 0.1 7 f0.05 0.17k 0.05 0.13 f 0.06 0.1 1 k0.06 0.08 f0.05
reports of acid-etch-retained veneers [3,221, resinbonded perforated [20] and etched cast prostheses [ 10,211 recommended no or little tooth preparation, mainly to provide patients with a nondestructive reversible procedure. Other reports recommended some tooth preparation to prevent unsightly margins at the periphery of porcelain veneers which would be difficult to finish [23], or to alter contour [l] or increase composite resin -enamel bond strength [24]. Calamia et al. [9] compared two groups of porcelain laminate veneers, one of 44 veneers without tooth preparation and another of 72 veneers placed using a chamfer preparation. They carried out a periodontal evaluation using stone replicas of the restored teeth to measure the height of the free gingival margin from the mid-facial to the edge of the restoration. Changes in gingival contour were also noted but not detailed in the report, which concluded that both groups caused ‘minimal periodontal response.’ However, in spite of this finding, and influenced by a report which suggested that an increase in ‘emergenceprofile’ of crowns may increase existing periodontal problems in patients with poor oral hygiene [7], tooth preparation was recommended [25]. It has been reported that in patients with healthy periodontal tissues and excellent oral hygiene the position of crown margin placement does not influence the chances of causing periodontal disease [26]. As patients receiving porcelain veneers must fall into this category, supragingivally-
placed restorations should not affect gingival health. This conclusion has been confirmed by the present study and by another [8] which showed no increased gingivitis related to veneers placed on unprepared teeth. Creugers et al. [ 101 placed resin-bonded metal prostheses supragingivally on unprepared teeth and concluded that preparation of abutment teeth to avoid overcontouring was not necessary to maintain gingival health. They used 10 test and control sites in 10 dental students. The trial was similar to ours in some respects in that gingival health was assessed during 10-day periods of normal tooth cleaning and of no tooth cleaning, using the same plaque index [ 121 and a papillary bleeding index [27]. No previous studies have included measurement of gingival crevicular fluid volumes. It is concluded that the evidence advanced in support of tooth preparation is unconvincing, and based on studies of full crown preparations. The results of the present study support those of Creugers et al. [ 101 in showing that supragingivally-placed restorations do not adversly affect gingival health in patients who have healthy gingivae and excellent oral hygiene. However, the effects of placing veneers on teeth of patients whose oral hygiene is inefficient cannot be ascertained from this study.
RksumC. La possibilite d’un effet nuisible sur la plaque dentaire et la sante des gencives de la part des protheses liees a la resine et graveis a l’acide fait l’objet d‘une controverse. Des experts recommandent l’absence de preparation avant l’application des vernis, quand d’autres preconisent la preparation de la dent pour prevenir des reactions des tissues de la gencive sans preparation de la dent, nous avons compare chez le meme individu la sante des gencives selon l’etat, verni ou non, des incisives maxillaires, pendant des periodes de nettoyage dentaire normal et des periodes de non nettoyage. Nous n’avons trouve aucune difference significative sur les index de plaque ou de gencive, sur le volume du fluide des crevasses gingivales, entre les 72 sites vernis ou non pendant le periode d’etude. La resultat de cette etude suggere que le vernisage a la porcelaine des dents non preparees n’accroit pas le risque de gingivite.
Porcelain veneers on maxillary incisors Zusammefassung. Die nachteilige Wirkung auf die Gingiva durch Prothesen und Porzelanschalen welche mit der Saureatztechnik aufgeklebt wurden, wird Z.Z. diskutiert. Einige Autoren sind fur eine vorgangige Zahnpraparation andere sind dagegen. Diese Studie vergleicht den Zustand der Gingiva an unpraparierten Frontzahnen welche mit Schalen uberdeckt wurden mit dem Zustand der Gingiva an nicht uberdeckte Frontzahne desselben Patienten. Es wurden 72 Zahne untersucht und vergichen. Keine signifikante Unterschiede bezuglich der Gesundheit der Gingiva wurden gefunden, d.h. Uberdeckung mit Schalen auf nicht praparierte Zahne erhoht nicht das Risiko einer Gingivits.
7
8 9
10
1
2
3
Resumen. El posible efecto daiiino de las pfotesis con grabado acido y veneers de porcelana en la acumulacion de placa y salud gingival se disputa actualmente. Algunos investigadores no recomiendan la preparacion del diente antes de colocar la veneer mientras que otros recomiendan la preparacion del diente para prevenir reacciones gingivales adversas. Para evaluar el posible efecto gingival de las veneers colocadas sin preparacion dentaria, este estudio compar6 la salud gingival de incisivos maxilares con veneers y sin veneers en el mismo paciente durante periodos de limpieza normal de 10s dientes y de no limpieza dental. No hub0 diferencias significativas en 10s indices de placa y gingival o en el volumen de fluido crevicular entre 10s 72 casos con y sin veneers durante el estudio. Los resultados sugieren que la colocacion de veneers de porcelana en dientes no preparados no aumenta el riesgo de gingivits.
21
References
22
1 McLean JW. Ceramics in clinical dentistry. British Dental Journal 1988; 164: 187-194. 2 Larson TD. Techniques for achieving realistic color distribution in large composite restorations. Journal of the American Dental Association 1986; 112: 669-672. 3 Christensen GT. Veneering of teeth. Dental Clinics of North America 1985; 2 9 373-391. 4 Quinn F, McConnell RJ, Byrne D. Porcelain laminates: a review. British Dental Journal 1986; 161: 61-65. 5 Jordan RE, Suzuki M, Gwinnett AJ. Conservative application of acid-etch resin techniques. Dental Clinics of North America 1981; 25: 307-345. 6 Muller HP. The effect of artificial crown margins at the gingival margin on the periodontal conditions in a group of periodontally supervised patients treated with fixed
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18 19
20
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25 26 27
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bridges. Journal of Clinical Periodontology 1986; 13 97-102. Sackett BP, Gildenhuys RR. The effect of axial crown overcontour on adolescents. Journal of Periodontology 1916; 47: 320-323. Reid JS, Murray MC, Power SM. Porcelain veneers a four year follow-up. Restorative Dentistry 1988; 4: 60-66. Calamia JR, Calamia S, Lemler J. Hamburg M, Scherer W. Clinical evaluation of etched porcelain laminate veneers: Results at 6 months-3 years. Journal of Dental Research 1987; 66, Special Issue, Abstract 1 1 10. Creugers NHJ, Snoek PA, Vogels ALM. Overcontouring in resin-bonded prostheses: plaque accumulation and gingival health. Journal of Prosthetic Dentistry 1988; 59: 17-21. Reid JS, McCrosson J. The clinical use of etched porcelain additions and veneers. Restorative Dentistry 1987; 3 4-6. Silness J, Loe H. Periodontal disease in pregnancy 11. Correlation between oral hygiene and periodontal condition. Acta Ondontologica Scandinavica 1964;22: 121-1 35. Lobene R, Weatherford T, Ross W, Lamm R, Menaker L. A modified gingival index for use in clinical trials. Clinical Preventive Dentistry 1986; 8 3-6. Ciancio S. Current status of indices ofgingivitis. Journal of Clinical Periodontology 1986; 1 3 375-378. Griffiths G, Curtis M, Wilton J. Selection of a filter paper with optimum properties for the collection of gingival crevicular fluid. Journal of Periodontal Research 1988; 23: 33-38. Loe H, Theilade E, Jensen M. Experimental gingivitis in humans. Journal of Periodontology 1965; 36: 177-1 87. Winkel E, Abbas F, Van der Velden U, Vroom T, Scholte G, Hart A. Experimental gingivitis in relation to age in individuals not suspectible to periodontal destruction. Journal of Clinical Periodontology 1987; 14: 499-501. Pincus CL. Building mouth personality. Californian State Dental Association Journal 1938; X I V 125-129. Buonocore MG. A simple method of increasing the adhesion of acrylic filling materials to enamel surfaces. Journal of Dental Research 1955; 3 4 849-853. Rochette AL. Attachment of a splint to enamel of lower anterior teeth. Journal of Prosthetic Dentistry 1913; 30: 4 18-423. Livaditis GJ, Thompson VP. Etched castings: An improved retentive mechanism for resin bonded retainers. Journal of Prosthetic Dentistry 1982; 47: 52-58. Calamia JR. Etched porcelain veneers: the current state of the art. Quintessence International 1985; 1: 5-12. Tay WM, Lynch E, Auger D. Effects of some finishing techniques on cervical margins of porcelain laminates. Quintessence International 1987; 18: 599-602. Schneider PM, Messer LB, Douglas WH. The effect of enamel surface reduction in vitro on bonding composite resin to permanent human enamel. Journal of Dental Research 1981; 6 0 895-900. Calamia JR. The etched porcelain veneer technique. New York State Dental Journal 1988; Aug-Sept: 49-50. Richter WA, Ueno H. Relationship of crown margin placement to gingival inflammation. Journal of Prosthetic Dentistry 1973; 3 0 156. Saxer UP, Turconi B, Elsasselr CH. Patient motivation with the papillary bleeding index. Journal of Preventive Dentistry 1977; 4; 20-22.
Gingival health associated with porcelain veneers on maxillary incisors J. S . R E I D ' , D . F. K I N A N E * & E. A D O N O G I A N A K 1 2 'Department of Conservative Dentistry, Glasgow Dental Hospital and School =Department of Periodontology, Glasgow Dental Hospital and School
Summary: The possible detrimental effect of acid-etched resin-bonded prostheses
and porcelain veneers on plaque accumulation and gingival health is currently disputed. Some workers recommend no tooth preparation prior to veneeringwhilst others recommend tooth preparation to prevent adverse gingival soft tissue reactions. In order to test the possible gingivaleffects of veneers placed without tooth preparation, this study was set up to compare gingival health on veneered and nonveneered maxillary incisors within the same individual during periods of normal tooth cleaning and of no tooth cleaning. No significant differences were noted in plaque or gingival indices, or in gingival crevicular fluid volume, between the 72 veneered and non-veneered sites during either study period. The results ofthis study suggest that placing porcelain veneers on unprepared teeth does not increase the risk of gingivitis.
Introduction There is some controversy about the effect of acidetched resin-bonded prostheses and porcelain veneers on plaque accumulation and gingivitis. Tooth preparation has been recommended before veneering to prevent overcontouring, as any increase in bulk may predispose to gingivitis [ 1-61. Other workers have recommended no tooth preparation and have found no adverse soft tissue reaction to prostheses or veneers [7- lo]. This study was designed to determine the effect on gingival health of acid-etched resin-bonded porcelain veneers cemented to unprepared labial surfaces of maxillary incisors, and to assess these effects during periods of normal tooth cleaning and of no tooth cleaning.
Methods Six dental students ( 5 male, 1 female) volunteered to take part in the study. They had no evidence Correspondenceto: Dr J. S. Reid, Department of Conservative Dentistry, Glasgow Dental Hospital and School, 378 Sauchiehall Street, Glasgow G2 352, UK.
of periodontal disease and no relevant medical histories. All the subjects (age range 20-2 1 years) had more than 26 teeth, a high standard of oral hygiene and healthy gingival tissues, with no pocketing greater than 3 mm. Fully informed consent was given by the volunteers, who were interviewed prior to commencing this study by the chairman and members of the local ethical committee.
Clinical procedures For each subject, a permanent maxillary central and adjacent lateral incisor were chosen to be veneered and the contralaterai teeth served as controls. All these teeth were sound, unrestored and vital. At the subject's first visit, alginate impressions were taken in stock trays and from the casts obtained an upper tray was constructed. The occlusion was checked for any occlusal interference and an occlusal registration was recorded using wax. At the second visit a master impression was recorded using an elastometric impression material (Provil M, Bayer, UK). Gingival tissues were not retracted. Tooth shade was recorded 137
138
J. S. Reid et al.
using a porcelain shade guide (Vita-Lumin, Germany). No tooth preparation was undertaken. The laboratory technician was instructed to construct two porcelain veneers as one unit joined at their approximal surfaces, to finish the veneers in a feather edge 1 mm supragingivally, and to add incisal cleats; the cleats acted as incisal stops to ensure the correct supragingival positioning of the gingival margin of the veeners. The teeth to be veneered were cleaned and isolated with rubber dam. The technique of acidetching and bonding the veneers to enamel has already been well described and is a standard technique [ 1 11. A light-cured enamel bonding agent was used (Scotchbond, 3M Healthcare). The veneers were finished using fine-fluted tungsten carbide burs and diamond polishing paste. The porcelain incisal cleats were removed using a highspeed water-cooled turbine. At the end of the study the porcelain veneers were removed.
Clinical assessments Plaque accumulation and gingival health were assessed and gingival crevicular fluid volumes were measured. All the data were collected by one of the authors (EA).
Plaque index. Plaque accumulation was assessed using the Plaque Index (PI) of Silness & Loe ( 1 964) [12], which is based on scoring the amount of plaque on the four tooth surfaces (approximal, lingual and labial) on a scale of 0-3. The lingual surface was not scored in the present study. Gingival index.The Lobene Index [ 131 scores the gingival condition of marginal and approximal tissues separately on a scale of 0-4. This index, termed the Modified Gingival Index (MGI), was calculated by examining the same sites as for the PI. Gingival crevicularfluid volume. Gingival crevicular fluid (GCF) volume was measured non-invasively from the veneer and control regions. During inflammation the volume of fluid increases in proportion with the degree of gingival inflammation, and direct volumetric GCF measurements can be used as a sensitive index of inflammation 1141.
Whatman grade 4 paper strips were used for the collection of GCF. Strips (2 x 13 mm2) were cut manually using a steel ruler and a scalpel, as recommended by previous investigators [ 151. A line was drawn 8 mm from the end of each strip, indicating the length of the paper to be inserted in the measuring instrument (Periotron 6000, Harco Electronics, Canada). Each crevicular site was carefully isolated with cotton rolls so that no saliva contamination of the samples occurred. Supragingival plaque was removed and the area was gently air-dried for 5 seconds and then left for 25 seconds prior to sampling. The paper strip was inserted into the crevice until mild resistance was felt, and was left there for 30 seconds. Care was taken to avoid mechanical injury of the tissues. After the collection of the GCF, the paper strip was transferred to the chairside-located ‘Periotron’ for quantification of the volume collected. Before commencing the study, a calibration graph was constructed for the Periotron 6000 in order to transform the digital readings from the filter strips into volumes and also to assess the accuracy of the instrument. Known volumes of serum diluted 1: 1 in phosphate-buffered saline were delivered to Whatman grade 4 paper strips with a Hamilton microsyringe in volumes ranging from 0.2 to 1 pl, in 0.2 pl increments. Each measurement was performed six times and the mean value for each volume was used in a linear regression analysis from which the slope and intercept were used to determine the volumes of crevicular fluid collected.
Statistical analysis Since each of the six subjects had two veneered teeth, data on PI, MGI and GCF were obtained from six veneer and six control sites in each patient (mesiolabial, mid-labial and distolabial), a total of 36 veneer and 36 control sites. Data from paired sites were compared using the nonparametric Wilcoxon signed rank test.
Study design To study the effect of the veneers during a period of no tooth cleaning, the human experimental gingivitis model introduced by Loe et al. (1965) [ 161 was used. This showed that cessation of oral
Porcelain veneers on maxillary incisors hygiene procedures by subjects with healthy gingivae leads to increased accumulation of bacterial plaque and subsequent development of gingival inflammation, which is completely reversible and resolves on re-institution of toothbrushing. This technique has been widely used [17] and has provided valuable information on the aetiology of periodontal disease. The study procedure was as follows:Day 0. Subjects were fitted with two maxillary anterior acid-etched resin-bonded porcelain veneers. Days 1-1 0: normal tooth cleaningperiod. Plaque and gingival scores were assessed every 3 days. The subjects employed their own normal oral hygiene procedures during this period. Days 11-13: rest period. Subjects were given a professional prophylaxis and three days later ceased cleaning their teeth. Days 14-35: no tooth cleaning period. Plaque, gingival and GCF scores were assessed every 3-4 days. Days 36-49. The subjects were given a thorough professional prophylaxis and instructed to recommence their normal oral hygiene procedures. PI and GI were assessed and GCF volumes determined after four days, one and two weeks. Day 49. The veneers were removed and the subjects recommenced oral’hygiene procedures.
Results Plaque and gingival indices are shown in Table 1. The plaque and gingival indices remained low or decreased during the 10-day normal oral hygiene period, rose steadily after oral hygiene was suspended at day 14, both indices peaking at day 35, and then fell after oral hygiene was reinstituted. The differences between veneered and control teeth for both plaque and gingival indices were not significant (for all paired analyses P>0.05). Although the data may suggest that there was a slower recovery to gingival health on veneered teeth, the differences were not statistically significant. Table 2 shows that GCF volume increased during the no-tooth-cleaningperiod and decreased when gingival health recovered. The differencesin mean GCF volume between veneered and control teeth were not significant.
Discussion An early report of the clinical use of porcelain veneers applied to unprepared teeth highlighted the benefits to those patients who did not want their teeth prepared [ 181. The introduction of the acid-etch technique [ 191allowed restorations to be bonded to enamel on a long-term basis. Initial
Table 1. Plaque and gingival indices during periods of normal toothcleaning (days 1-10), of no toothcleaning (days 14-35), and after resumption of toothcleaning (days 36-49). Mean scores ( fSD) of 36 veneer and 36 control sites (six of each in each of 6 subjects). Plaque index Day 1 4 7 14 18 21 25 28 31 35 39 42 49
139
Gingival index
Veneer sites mean fSD
Control sites mean fSD
Veneer sites mean f SD
Control sites mean fSD
0.50f0.14 0.28k0.45 0.35f0.13 0.41 k0.02 1.32k0.07 1.73f0.1 1 1.92f0.07 2.00k0.10 1.99 f 0 . 1 2 2.36f0.10 0.44f0.06 0.13f0.07 0.27f0.14
0.28 k 0.05 0.31 fO.10 0.18 f0.06 0.30f 0.18 1.43f0.5 5 1.54k0.07 1.96f 0.05 2.22f 0.07 2.4 1 f0.34 2.40 f 0.04 0.24 k 0.08 0. I9 k 0.06 0.33 f0.09
0.56 k 0.12 0.19 k0.06 0.39 f0.06 0.22 k 0.05 0.82 f0.13 1.31 20.03 1.93 f0.06 2.3 1 f 0.09 2.79 f 0.02 3.09 f0.12 1.98 f 0.03 1.07 & 0.18 0.73 f 0.1 4
0.37 f0.12 0.70 f0.08 0.35 f0.13 0.38 f0-06 1.04k0.19 1.45f0.22 2.1920.02 2.5 1 f 0.09 2.88 f 0.04 2.97 f 0.06 2.4 1 f 0.09 1.48 f 0.1 1 1.25f0.22
140
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Table 2. Gingival crevicular fluid volumes @I) during a period of no toothcleaning (days 14-35) and after resumption of toothcleaning (days 36-49). Mean values ( fSD) of 36 veneer and 36 control sites (six of each in each of six subjects).
Day
Veneer sites mean k SD
Control sites mean k SD
14 18 21 25 28 31 35 39 42 49
0.05 f0.04 0.12 f0.07 0.20 f0.13 0.13 k 0.03 0.14 f0.06 0.20 k 0.08 0.16 f0.07 0.09 f0.05 0.10 f0.05 0.07 f0.05
0.06 f0.05 0.19 k 0.03 0.1 5 f0.08 0.19 a0.12 0.17f 0.03 0.1 7 f0.05 0.17k 0.05 0.13 f 0.06 0.1 1 k0.06 0.08 f0.05
reports of acid-etch-retained veneers [3,221, resinbonded perforated [20] and etched cast prostheses [ 10,211 recommended no or little tooth preparation, mainly to provide patients with a nondestructive reversible procedure. Other reports recommended some tooth preparation to prevent unsightly margins at the periphery of porcelain veneers which would be difficult to finish [23], or to alter contour [l] or increase composite resin -enamel bond strength [24]. Calamia et al. [9] compared two groups of porcelain laminate veneers, one of 44 veneers without tooth preparation and another of 72 veneers placed using a chamfer preparation. They carried out a periodontal evaluation using stone replicas of the restored teeth to measure the height of the free gingival margin from the mid-facial to the edge of the restoration. Changes in gingival contour were also noted but not detailed in the report, which concluded that both groups caused ‘minimal periodontal response.’ However, in spite of this finding, and influenced by a report which suggested that an increase in ‘emergenceprofile’ of crowns may increase existing periodontal problems in patients with poor oral hygiene [7], tooth preparation was recommended [25]. It has been reported that in patients with healthy periodontal tissues and excellent oral hygiene the position of crown margin placement does not influence the chances of causing periodontal disease [26]. As patients receiving porcelain veneers must fall into this category, supragingivally-
placed restorations should not affect gingival health. This conclusion has been confirmed by the present study and by another [8] which showed no increased gingivitis related to veneers placed on unprepared teeth. Creugers et al. [ 101 placed resin-bonded metal prostheses supragingivally on unprepared teeth and concluded that preparation of abutment teeth to avoid overcontouring was not necessary to maintain gingival health. They used 10 test and control sites in 10 dental students. The trial was similar to ours in some respects in that gingival health was assessed during 10-day periods of normal tooth cleaning and of no tooth cleaning, using the same plaque index [ 121 and a papillary bleeding index [27]. No previous studies have included measurement of gingival crevicular fluid volumes. It is concluded that the evidence advanced in support of tooth preparation is unconvincing, and based on studies of full crown preparations. The results of the present study support those of Creugers et al. [ 101 in showing that supragingivally-placed restorations do not adversly affect gingival health in patients who have healthy gingivae and excellent oral hygiene. However, the effects of placing veneers on teeth of patients whose oral hygiene is inefficient cannot be ascertained from this study.
RksumC. La possibilite d’un effet nuisible sur la plaque dentaire et la sante des gencives de la part des protheses liees a la resine et graveis a l’acide fait l’objet d‘une controverse. Des experts recommandent l’absence de preparation avant l’application des vernis, quand d’autres preconisent la preparation de la dent pour prevenir des reactions des tissues de la gencive sans preparation de la dent, nous avons compare chez le meme individu la sante des gencives selon l’etat, verni ou non, des incisives maxillaires, pendant des periodes de nettoyage dentaire normal et des periodes de non nettoyage. Nous n’avons trouve aucune difference significative sur les index de plaque ou de gencive, sur le volume du fluide des crevasses gingivales, entre les 72 sites vernis ou non pendant le periode d’etude. La resultat de cette etude suggere que le vernisage a la porcelaine des dents non preparees n’accroit pas le risque de gingivite.
Porcelain veneers on maxillary incisors Zusammefassung. Die nachteilige Wirkung auf die Gingiva durch Prothesen und Porzelanschalen welche mit der Saureatztechnik aufgeklebt wurden, wird Z.Z. diskutiert. Einige Autoren sind fur eine vorgangige Zahnpraparation andere sind dagegen. Diese Studie vergleicht den Zustand der Gingiva an unpraparierten Frontzahnen welche mit Schalen uberdeckt wurden mit dem Zustand der Gingiva an nicht uberdeckte Frontzahne desselben Patienten. Es wurden 72 Zahne untersucht und vergichen. Keine signifikante Unterschiede bezuglich der Gesundheit der Gingiva wurden gefunden, d.h. Uberdeckung mit Schalen auf nicht praparierte Zahne erhoht nicht das Risiko einer Gingivits.
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Resumen. El posible efecto daiiino de las pfotesis con grabado acido y veneers de porcelana en la acumulacion de placa y salud gingival se disputa actualmente. Algunos investigadores no recomiendan la preparacion del diente antes de colocar la veneer mientras que otros recomiendan la preparacion del diente para prevenir reacciones gingivales adversas. Para evaluar el posible efecto gingival de las veneers colocadas sin preparacion dentaria, este estudio compar6 la salud gingival de incisivos maxilares con veneers y sin veneers en el mismo paciente durante periodos de limpieza normal de 10s dientes y de no limpieza dental. No hub0 diferencias significativas en 10s indices de placa y gingival o en el volumen de fluido crevicular entre 10s 72 casos con y sin veneers durante el estudio. Los resultados sugieren que la colocacion de veneers de porcelana en dientes no preparados no aumenta el riesgo de gingivits.
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References
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