Are Predoctoral Students Able to Provide Single Tooth Implant ...

Are Predoctoral Students Able to Provide Single Tooth Implant Restorations in the Maxillary Esthetic Zone? Emily J. Taylor, D.M.D., M.S.; Judy Chia-Chun Yuan, D.D.S., M.S.; Damian J. Lee, D.D.S., M.S.; Rand Harlow, D.D.S.; Fatemeh S. Afshari, D.M.D., M.S.; Kent L. Knoernschild, D.M.D., M.S.; Stephen D. Campbell, D.D.S., M.M.Sc.; Cortino Sukotjo, D.D.S., M.M.Sc., Ph.D. Abstract: The objective of this study was to assess the ability of the University of Illinois at Chicago College of Dentistry (UICCOD) predoctoral students to provide single tooth implant (STI) prostheses in the maxillary esthetic zone. The patient’s esthetic satisfaction and the correlation between prosthodontists’ and patients’ perspectives were examined. Twenty-seven patients were recruited for recall examinations at the UIC-COD predoctoral implant program and underwent clinical and radiographic examination with clinical photographs of the implant sites. The patients completed a semantic differential scale questionnaire. The collected information was formulated into a PowerPoint presentation for two Diplomate of the American Board of Prosthodontists to use the Pink/White Esthetic Score (PES/WES) to evaluate the esthetic outcome. Descriptive analyses, Cohen kappa test, and Spearman rank correlation coefficient test were performed. The average PES/WES were above 6.0 (out of 10). The median for the patient satisfaction and esthetic outcome questionnaires were 10 and 9, respectively, on a scale with 10=highest. There was a medium and positive correlation between prosthodontists’ and patients’ perspectives in esthetic outcome. This study found that, with strict guidance and proper selection criteria, predoctoral students were able to provide esthetically acceptable STI prostheses in the maxillary esthetic zone and patients were satisfied with the treatment provided. Dr. Taylor is a former resident in Advanced Graduate Program in Prosthodontics, Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago; Dr. Yuan is Assistant Professor and Director of Predoctoral Implant Program, Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago; Dr. Lee is former Assistant Professor, Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago; Dr. Harlow is Clinical Assistant Professor and former Director of Predoctoral Implant Program, Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago; Dr. Afshari is Clinical Assistant Professor, Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago; Dr. Knoernschild is Professor and Director, Advanced Prosthodontics, Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago; Dr. Campbell is Professor and Head, Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago; and Dr. Sukotjo is Assistant Professor, Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago. Direct correspondence and requests for reprints to Dr. Cortino Sukotjo, Department of Restorative Dentistry, University of Illinois at Chicago, College of Dentistry (MC 555), 801 South Paulina Street, Room 365B, Chicago, IL 60612-7211; 312-355-0360; [email protected]. Keywords: dental education, implant dentistry, dental implant therapy, single tooth implant, dental students, esthetic zone Submitted for publication 5/21/13; accepted 9/21/13

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ecent clinical studies have demonstrated that survival rates of implants provided by predoctoral dental students are comparable to those provided by experts.1-3 With an increased demand for esthetic restorations,4,5 dental students are now delivering implant prostheses that involve the esthetic zone. However, dental schools may be hesitant about allowing their students to provide implant treatment in the esthetic zone.2,6,7 Implant esthetics in the maxillary anterior region is challenging and dictated by multiple factors, including the soft tissue architecture, shade matching, and crown contours.5,8 Therefore, it is important that dental students learn during their training to manage the soft

May 2014 ■ Journal of Dental Education

and hard tissue around implant prostheses to meet patient demands. There have been multiple attempts to objectively assess the esthetic results of implant prostheses using various grading scores including the Pink Esthetic Score (PES) and White Esthetic Score (WES).9-12 The PES is used to assess the gingival architecture surrounding an anterior single tooth implant. PES variables are the mesial papilla, distal papilla, softtissue level, soft-tissue contour, alveolar process deficiency, soft-tissue color, and soft-tissue texture (Table 1).9 The WES incorporates five assessment criteria, including general tooth form, outline and volume of the clinical crown, and color (Table 2).10

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Table 1. Pink Esthetic Score (PES) Parameter Mesial papilla Distal papilla

Absent

Incomplete

Complete

0 0

1 1

2 2

Major Discrepancy

Minor Discrepancy

No Discrepancy

Curvature of facial mucosa 0 1 Level of facial mucosa 0 1 Root convexity/soft tissue color and texture 0 1 Maximum total PES score

2 2 2 10

Table 2. White Esthetic Score (WES) Parameter

Major Discrepancy

Minor Discrepancy

Tooth form 0 1 Tooth volume/outline 0 1 Color (hue/value) 0 1 Surface texture 0 1 Translucency 0 1 Maximum total WES score

The clinically acceptable threshold for PES/WES is 6 (out of 10). Using these two assessment tools, one can evaluate the esthetic outcomes of single implant teeth in the esthetic zone at the predoctoral level. Aside from esthetic outcomes, quality of life assessment is an important factor to consider when quantifying patient satisfaction. There are multiple ways to measure the quality of life and patient satisfaction. One of the most common instruments to investigate quality of life in relation to oral disorder/ treatment is the Oral Health Impact Profile (OHIP) survey. Furthermore, instruments such as the visual analog scale (VAS)10,13 and the semantic differential scale10,14 have been developed recently to measure dental treatment-related patient satisfaction. In the past, the semantic differential scale has been used to measure patient satisfaction of endodontic treatment in relation to esthetics, function, and cost based on a series of continuous bipolar scales.14 The semantic differential is one of the most widely used scales for the measurement of attitudes.15 Recently, this scale was used to evaluate predoctoral dental education on the subject of geriatric dentistry and predoctoral students’ attitudes toward working with geriatric patients.16 By combining the esthetic scores and the semantic differential scale, one may be able to assess both subjective and objective outcomes of dental implant therapy.

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No Discrepancy 2 2 2 2 2 10

The aim of this study was to assess the ability of predoctoral students at the University of Illinois at Chicago College of Dentistry (UIC-COD) to provide esthetically acceptable single tooth implant prostheses in the maxillary esthetic zone (anterior or premolar sites)10,17,18 using the PES/WES. As a typical smile has been suggested to include the maxillary six anteriors and first premolars,19 this study follows the similar inclusion for esthetic zone. The patient’s esthetic satisfaction was also investigated with the semantic differential scale, and the relationship between total PES/WES and the semantic differential scale question #4 (regarding esthetic outcome) was examined.

The Predoctoral Implant Program at UIC-COD Parts of the Predoctoral Implant Program at UIC-COD were described in previous articles.3,20 In this program, a systematic protocol and diagnostic checklist were developed to guide the students in screening potential implant patients during the restorative and surgical consultation (Table 3). The selection criteria were based partially on the Prosthodontic Diagnostic Index for partially edentulous patients as well as other criteria listed in Table 3.21 As the inci-

Journal of Dental Education ■ Volume 78, Number 5

Table 3. Predoctoral clinical implant program for partially edentulous patients, single tooth implant prostheses: diagnostic checklist Criteria

Yes No

1. Patient’s dental record is complete: appropriate forms in the Axium EHR are completed and approved. 2. Medical history has been reviewed and is current. 3. Patient is ASA Class I, II, or III. 4. Psychosocial considerations: patient expectations are conducive to successful implant therapy; patient has no major psychological conditions. 5. Periapical and panoramic radiographs are current. 6. Adequate bone width is present in the edentulous site: a minimum of 7 mm is present between the adjacent teeth (or can be achieved with minimal enameloplasty). 7. Radiographic bone height: maxilla or anterior mandible >10 mm of bone at the implant site. 8. Interocclusal spacing: a minimum of 7 mm from ridge to opposing tooth marginal ridge. 9. Crown:implant ratio a minimum of 1:1. 10. Facial-lingual ridge width ≥7 mm as measured 3-4 mm below the crest of the ridge. 11. Keratinized tissue width ≥4mm faciolingually. 12. Surgical intervention: no surgical revision of the implant site is indicated or can be corrected at the time of implant placement. 13. An adequate diagnostic cast and wax-up have been made. 14. Excluded teeth: the area(s) to be restored are NOT one of the following: #1, 2, 8, 9, 15, 16, 17, 18, 23-26, 31, 32 unless obtained approval by predoctoral implant program director.

dence of anterior ridge deformities after extraction in partially edentulous patients is high,22 strict and comprehensive patient selection criteria that involved hard and soft tissue analysis for implant surgery were followed. Excluded area/tooth to be restored was also assessed in the checklist. Furthermore, students needed to provide a diagnostic wax-up of the edentulous area, as well as a panoramic radiograph from within the last three years and up-to-date periapical radiographs of the recent extraction site. All these initial screening procedures and final prosthetic treatment were performed by third- and fourth-year dental students and second-year International Dentist Program students in a designated predoctoral implant clinic supervised by four calibrated full-time prosthodontists. The four prosthodontists discussed the uncertain patient scenarios together and reviewed the clinical protocols during monthly one-hour meetings. If discrepancies occurred, the director of the program was responsible for making a final decision. Patients were referred to the advanced prosthodontics clinic upon any deviation from the diagnostic checklist. Once the patient was approved for predoctoral care, the patient was assigned to the oral and maxillofacial surgery (OMFS), periodontics, or prosthodontics discipline for surgical consultation and procedures based on a predetermined ratio of


40 percent, 40 percent, and 20 percent, respectively. The surgical procedures were provided by advanced residents with various levels of training: fourth-year OMFS residents, second- and third-year periodontic residents, and second- and third-year prosthodontic residents. The two-stage surgical protocol was followed with a recommended three to four months healing for the first stage and three to four weeks of healing time after second-stage surgery. The implant level and closed tray impression technique were used for most of restorative procedures under the supervision of prosthodontic faculty in the implant clinic. Patients were urged to wear a removable prosthesis to meet their esthetic needs and prevent shifting of the remaining teeth. However, fixed provisional restorations during the transitional stage were not provided.

Materials and Methods This study protocol was reviewed and approved by the Institutional Review Board at UIC (IRB#20120396). Study inclusion criteria were 1) subject had to voluntarily participate by signing an informed consent, 2) be over the age of eighteen, and 3) must have received a single tooth implant prosthesis placed in the maxillary esthetic zone (spanning from first premolar to first premolar). Patients were excluded

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from the study if the contralateral tooth (for canine through canine) or adjacent second premolar (for first premolars) was missing or had a full coverage restoration. Following the initial chart screening from the UIC-COD predoctoral implant program, fifty-three patients who received single tooth implants (STIs) from 2006-12 were identified. These subjects were contacted and recruited for a recall examination. All implant placement and restorations were completed following specific predoctoral implant program surgical and restorative protocols. The implants were placed by the UIC-COD specialty program residents. No surgical intervention at the implant site was performed, with guided bone regeneration, internal sinus elevation, and ridge split being exclusion criteria for the predoctoral protocol. All coronal prostheses were provided by predoctoral students and had been in function for at least six months prior to recall. A clinical examination was performed according to the design of a previously published study.10 During the recall appointment, one parallel technique periapical radiograph was taken of the implant prosthesis. Implant survivability was evaluated clinically by performing a percussion test, mobility test, and soft tissue examination to detect any suppuration or inflammation.23 Intraoral photographs were taken of all implant prostheses with a Canon EOS Rebel SLR camera, Canon Macro Lens EF 100 mm, and Canon Macro Ring Lite MR-14EX (all three Canon U.S.A., Inc., Melville, NY, USA) by a single operator (EJT) at a magnification between 1:2 and 1:3. For implant prostheses placed from canine to canine, photographs were centered at the midline to capture a symmetrical representation of the contralateral tooth. If necessary, an additional photograph perpendicular to the anterior tooth was taken to capture mesial and distal papillae. In the case of first premolars, the method was modified to capture the adjacent second premolar as the reference tooth. In all photographs, special efTable 4. Semantic differential scale data reported by twenty-seven patients (scale 1-10 on each item as shown) My treatment was:

Median

Expensive (1) to Inexpensive (10) 6 Time-consuming (1) to Quick (10) 5 Painful (1) to Pain-free (10) 8 Poor esthetics (1) to Good esthetics (10) 9 Poor chewing ability (1) to Good chewing ability (10) 10 Unpleasant (1) to Pleasant (10) 9 Very dissatisfied (1) to Very satisfied (10) 10

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fort was made to capture the adjacent teeth and the gingival architecture. To help in determining the root and gingival structures, maxillary study casts were poured in type III dental stone (Coecal, GC America Inc., Alsip, IL, USA) from maxillary impressions made with irreversible hydrocolloid (Jeltrate Plus, Dentsply Caulk, Milford, DE, USA). All patients completed semantic differential scales that measured their satisfaction with the implant treatment.14 The semantic differential scale consists of seven questions to measure subjective evaluation of treatment received by using horizontal bars of 100 mm length (Table 4). Question #4 specifically addressed the esthetic outcome, ranging from poor to good esthetics. Three Diplomates of the American Board of Prosthodontists were recruited to evaluate the collected data. Prior to their assessment, each examiner completed a color vision test (www.colour-blindness. com/colour-blindness-tests/ishihara-colour-testplates/). Upon passing the test, the examiner assessed a presentation (Microsoft PowerPoint 2007, Seattle, WA, USA) on a color computer monitor (Dell, Round Rock, TX, USA) of all included patients with the intraoral photographs, implant site specified, and periapical radiograph. The study casts were provided, and the site of interest specified. The examiners were blind to the patient information. Each examiner was asked to assess the photographs twice using the PES/ WES as outlined in a previous study (Tables 1 and 2).10 The order of photographs was changed from the first to the second assessment, which was scheduled at least two weeks after the first. If the examiner was not consistent between the two assessments, he or she was asked to select one value to allow for interexaminer assessment. Data were collected and coded into a software database (Microsoft Excel 2007, Seattle, WA, USA). Descriptive analyses were generated, including information on gender, age, abutment style, and site of prosthesis. The data were not normally distributed, and therefore nonparametric tests were used. The Cohen kappa test was used to analyze the reliability between the two assessment times by the same examiner. To assess the correlation between total PES/WES and semantic differential scale question regarding esthetics (#4), the Spearman rank correlation coefficient was calculated. Statistical software (SPSS v. 20.0, IBM Corp., Armonk, NY, USA) was used for descriptive and statistical analyses. For all analyses, a p-value of 6.0 with PES slightly higher than WES. The majority of the patients reported high satisfaction with their implant treatment (score 10, on a scale with 10=highest), the exception being

Discussion The UIC-COD predoctoral implant program was established in 2006 with a goal of providing predoctoral students with a comprehensive implant curriculum focusing on single tooth implant and mandibular two-implant overdenture patient care.3,20 The program’s curriculum has been modified to prepare the students to be competent in providing comprehensive care with greater diversity of implant-supported prostheses. For example, the patient selection has been expanded to include anterior teeth (except for central incisors), immediate placement strategy for single tooth implant, and introduction of advanced technology in implant dentistry, such as the fabrication of digitally designed and fabricated abutments. The objective esthetic assessments from this study suggest that predoctoral students at UIC are capable of providing clinically acceptable esthetic implant prostheses in the esthetic zone. The overall PES/WES was 6.05/6.04, which meets the standard of clinical acceptability.10 Our values were slightly lower than those in the Belser et al. study.10 It is important to note that, in their study, a single experienced surgical operator placed the implants, and restorations were performed by referred general dentists. At UIC-COD, implants were surgically placed by residents from three specialties with different levels of experience and with various attending faculty. Also, the implant placement timeline protocol may contribute to variability in soft tissue esthetics.24 The predoctoral implant placement protocol at UIC-COD is delayed, possibly leading to decreased bone levels post extraction, which in turn may affect the PES.22,25

Table 5. Distribution of implants treated by predoctoral students Implant Site N, %

#5

#6

#7

#9

#10

#12

17, 63%

2, 7%

2, 7%

1, 4%

1, 4%

4, 15%


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PES

Mesial Papilla

Distal Papilla

Curvature of Facial Mucosa

Level of Facial Mucosa

Root Convexity, Soft Tissue Color, and Texture

Total PES (Max 10)

Score

2

1

1

2

2

8

WES

Tooth Form

Tooth Volume/ Outline

Color (Hue/ Value)

Surface Texture

Translucency and Characterization

Total WES (Max 10)

Score

2

2

2

2

2

10

Figure 1. Example of high PES/WES scores for tooth #7

PES

Mesial Papilla

Distal Papilla




Total PES (Max 10)

Score

0

1

1

1

1

4

WES

Tooth Form


Color (Hue/ Value)

Surface Texture


Total WES (Max 10)

Score

1

1

2

1

1

6

Figure 2. Example of moderate PES/WES scores for tooth #5

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PES

Mesial Papilla

Distal Papilla




Total PES (Max 10)

Score

1

0

0

0

0

1

WES

Tooth Form


Color (Hue/ Value)

Surface Texture


Total WES (Max 10)

Score

0

0

0

1

0

1

Figure 3. Example of low PES/WES scores for tooth #5

Table 6. Kappa, PES, and WES results from two examiners Examiner

Kappa Value*

Prosthodontist 1 0.417 Prosthodontist 2 0.552 Prosthodontists 1+ 2

Average PES

Average WES

Average Total

6.15±2.62 5.96±2.10 6.05±2.35

6.44±2.85 5.63±2.72 6.04±2.79

12.50±4.40 11.60±4.04 12.09±4.21

*Strength of agreement: ≤0.2 poor; 0.21-0.4 fair; 0.41-0.6 moderate; 0.61-0.8 good; 0.81-1.0 very good. PES: pink esthetic score, WES: white esthetic score

One recent study reported that esthetic scores in the delayed group were slightly lower compared to immediate placement group.26 Further, the diversity of the implant manufactures may contribute to the PES results; however, such a factor could not be explored in our study due to the small sample size. The clinically acceptable PES of this study may be attributed to the stringent patient selection criteria in the predoctoral implant program as only Prosthodontic Diagnostic Index Class I and II patients were accepted into the program.21 As part of the UIC-COD predoctoral implant program patient selection protocol, minimum height and width of the alveolar ridge are 10 mm and 7 mm, respectively, at the implant sites. Factors such as the patient’s bony anatomy, type of mucosa, and surgical approach to implant therapy can have positive or negative impacts on the resulting PES.24 In the predoctoral implant program, soft and


hard tissue development is not allowed in advance of implant placement due to case complexity. Patients requiring augmentation are referred to the specialty programs. It is the philosophy of the program that predoctoral students treat simple and straightforward patient conditions. WES in this study was also comparable to a previous study.13 This may be attributed to the standardization and consistency of laboratory work in the predoctoral implant program and laboratory quality assurance within the institution.27 In the clinic, implant-supported prostheses are supervised by prosthodontists, which may contribute to the acceptable values. However, the use of titanium abutments and porcelain fused to metal restorations for the majority of the patients may contribute to the scores’ overall low value. One study has shown that all-ceramic crown/abutment may have contributed

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Figure 4. Correlation between total PES and WES scores and semantic score question 4 (n=27)

to higher PES/WES.28 Perhaps the use of all-ceramic abutments and crowns in the future would show an increase in esthetic outcome values. Patient satisfaction was an important outcome of our study. The patients were satisfied with the esthetic outcome of the STI prosthesis and felt they received excellent care in various aspects of their treatment in the UIC-COD predoctoral implant program. Perhaps not surprisingly, the lowest scores were given to expense and timeliness. Care in the academic setting is more affordable than in private practice; however, it often requires extended time, as each step during treatment must be approved by the instructor and the ultimate goal is student education. Both patients and clinicians reported clinically acceptable esthetic score outcomes; however, the patients’ view of their esthetic results and the examiners’ assessments were not always strongly correlated (r=0.237, p=0.233). Other studies also found poor agreement between patients’ and clinicians’ outcomes assessment.29 These findings are important because providers must consider the patient’s perspective when fabricating prostheses. Understanding patient expectations allows the provider to better manage

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treatment outcomes and optimize patient satisfaction. One additional factor of discrepancy between patients’ and clinicians’ perspective could be the lip line and its position. As most of the patients reveal 75-100 percent of the maxillary teeth and the interproximal gingival when smiling,19 patients may not be as critical as the clinicians for PES. There are a few limitations to this study. Although over fifty patients were contacted to participate in the study, only twenty-seven qualified and participated. The small sample size makes it difficult to draw any larger conclusions, though trends in the treatment at the predoctoral level can be observed. Further, most of the implant prostheses were at the premolar sites. Some may argue that these sites are not included in the traditional esthetic zones and the results may be premature and somewhat misleading. However, other studies have defined the maxillary esthetic zone more broadly.10,13 In addition, the thickness and quality of gingival tissues were not included in the analysis of this study and may play a role in the outcomes.30,31 In this study, the supervision of restorative procedures in the clinic was performed by full-time prosthodontists, and the subsequent evalu-


ations of the study were performed by Diplomates of the American Board of Prosthodontists. Not every school has a similar educational setting. The strict diagnostic selection criteria provided in this study support faculty standardization/calibration. This may also help those institutions that do not have faculty with advanced prosthodontics training to achieve similar results.

Conclusion Within the limitations of the study, our findings suggest that, with strict guidance and proper selection criteria, predoctoral students at the UIC-COD were able to provide an esthetically acceptable implant restoration in the maxillary esthetic zone. Furthermore, patients were highly satisfied with the esthetic outcomes of their implant treatment. A future study that includes mostly anterior restorations and uses more comprehensive assessment criteria, such as gingival types, and thickness, is currently under way.

REFERENCES

1. Andersson B, Odman P, Lindvall AM, Branemark PI. Five-year prospective study of prosthodontic and surgical single-tooth implant treatment in general practices and at a specialist clinic. Int J Prosthodont 1998;11(4):351-5. 2. Wilcox CW, Sheets JL, Nilsson DE. Predoctoral implant education: the Creighton experience at 20 years. J Prosthodont 2010;19(2):144-9. 3. Lee DJ, Harlow RE, Yuan JC, et al. Three-year clinical outcomes of implant treatments provided at a predoctoral implant program. Int J Prosthodont 2011;24(1):71-6. 4. Paravina RD, O’Neill PN, Swift EJ Jr, et al. Teaching of color in predoctoral and postdoctoral dental education in 2009. J Dent 2010;38(Suppl 2):e34-40. 5. Gehrke P, Degidi M, Lulay-Saad Z, Dhom G. Reproducibility of the implant crown aesthetic index: rating aesthetics of single-implant crowns and adjacent soft tissues with regard to observer dental specialization. Clin Implant Dent Relat Res 2009;11(3):201-13. 6. Jalbout Z, El Chaar E, Hirsch S. Dental implant placement by predoctoral dental students: a pilot program. J Dent Educ 2012;76(10):1342-6. 7. Jahangiri L, Choi M. A model for an integrated predoctoral implant curriculum: implementation and outcomes. J Dent Educ 2008;72(11):1304-17. 8. Nisapakultorn K, Suphanantachat S, Silkosessak O, Rattanamongkolgul S. Factors affecting soft tissue level around anterior maxillary single-tooth implants. Clin Oral Implants Res 2010;21(6):662-70. 9. Furhauser R, Florescu D, Benesch T, et al. Evaluation of soft tissue around single-tooth implant crowns: the pink esthetic score. Clin Oral Implants Res 2005;16(6):639-44. 10. Belser UC, Grutter L, Vailati F, et al. Outcome evaluation of early placed maxillary anterior single-tooth implants


using objective esthetic criteria: a cross-sectional, retrospective study in 45 patients with a 2- to 4-year followup using pink and white esthetic scores. J Periodontol 2009;80(1):140-51. 11. Meijer HJ, Stellingsma K, Meijndert L, Raghoebar GM. A new index for rating aesthetics of implant-supported single crowns and adjacent soft tissues: the implant crown aesthetic index. Clin Oral Implants Res 2005;16(6):645-9. 12. Gehrke P, Lobert M, Dhom G. Reproducibility of the pink esthetic score: rating soft tissue esthetics around single-implant restorations with regard to dental observer specialization. J Esthet Restor Dent 2008;20(6):375-84. 13. Cho HL, Lee JK, Um HS, Chang BS. Esthetic evaluation of maxillary single-tooth implants in the esthetic zone. J Periodontal Implant Sci 2010;40(4):188-93. 14. Dugas NN, Lawrence HP, Teplitsky P, Friedman S. Quality of life and satisfaction outcomes of endodontic treatment. J Endod 2002;28(12):819-27. 15. Munro S, Baker JA. Surveying the attitudes of acute mental health nurses. J Psychiatr Ment Health Nurs 2007;14(2):196-202. 16. De Visschere L, Van Der Putten GJ, de Baat C, et al. The impact of undergraduate geriatric dental education on the attitudes of recently graduated dentists towards institutionalised elderly people. Eur J Dent Educ 2009; 13(3):154-61. 17. Bashutski JD, Wang HL, Rudek I, et al. The effect of flapless surgery on single-tooth implants in the esthetic zone: a randomized clinical trial. J Periodontol 2013;84(12): 1747-54. 18. Oh TJ, Shotwell J, Billy E, et al. Flapless implant surgery in the esthetic region: advantages and precautions. Int J Periodontics Restorative Dent 2007;27(1):27-33. 19. Tjan AH, Miller GD, The JG. Some esthetic factors in a smile. J Prosthet Dent 1984;51(1):24-8. 20. Yuan JC, Kaste LM, Lee DJ, et al. Dental student perceptions of predoctoral implant education and plans for providing implant treatment. J Dent Educ 2011;75(6):750-60. 21. McGarry TJ, Nimmo A, Skiba JF, et al. Classification system for partial edentulism. J Prosthodont 2002;11(3): 181-93. 22. Abrams H, Kopczyk RA, Kaplan AL. Incidence of anterior ridge deformities in partially edentulous patients. J Prosthet Dent 1987;57(2):191-4. 23. Smith DE, Zarb GA. Criteria for success of osseointegrated endosseous implants. J Prosthet Dent 1989;62(5): 567-72. 24. Chu SJ, Salama MA, Salama H, et al. The dual-zone therapeutic concept of managing immediate implant placement and provisional restoration in anterior extraction sockets. Compend Contin Educ Dent 2012;33(7):524-32,34. 25. Covani U, Bortolaia C, Barone A, Sbordone L. Buccolingual crestal bone changes after immediate and delayed implant placement. J Periodontol 2004;75(12):1605-12. 26. Felice P, Soardi E, Piattelli M, et al. Immediate nonocclusal loading of immediate post-extractive versus delayed placement of single implants in preserved sockets of the anterior maxilla: 4-month post-loading results from a pragmatic multicentre randomized controlled trial. Eur J Oral Implantol 2011;4(4):329-44.

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27. Chan CT, Sukotjo C, Gehrke KW, et al. Laboratory quality assurance in the Department of Restorative Dentistry at the University of Illinois at Chicago, College of Dentistry. J Prosthodont 2013;22(1):85-91. 28. Gallucci GO, Grutter L, Nedir R, et al. Esthetic outcomes with porcelain-fused-to-ceramic and all-ceramic singleimplant crowns: a randomized clinical trial. Clin Oral Implants Res 2011;22(1):62-9.

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29. Esposito M, Grusovin MG, Worthington HV. Agreement of quantitative subjective evaluation of esthetic changes in implant dentistry by patients and practitioners. Int J Oral Maxillofac Implants 2009;24(2):309-15. 30. Jung RE, Sailer I, Hammerle CH, et al. In vitro color changes of soft tissues caused by restorative materials. Int J Periodontics Restorative Dent 2007;27(3):251-7. 31. Serio FG, Strassler HE. Periodontal and other soft tissue considerations in esthetic dentistry. J Esthet Dent 1989;1(6):177-88.
