Research Article
Knowledge, Attitude, and Practice of Various Impression Techniques Available for Dental Implants among Dental Students and Dental Practitioners - A survey Fahmida Binti Abd Rahman1, Ashish R. Jain2* ABSTRACT Background: Dental implant is a surgical component that supports dental prosthesis such as crown, bridge, denture, and facial prosthesis to the bone or jaw of the skull. Osseointegration is a biologic process that acts as the basis for modern dental implant in which materials such as titanium form an intimate bond to bone. A variable impression technique can be used for this kind of procedure. Aim: This study aims to assess the knowledge, attitude, and practice of undergraduate students and dental practitioners toward different impression techniques used for implant procedure. Materials and Methods: The study was conducted as a descriptive survey of private dental practitioners in the Chennai city, Tamil Nadu, India. A selfadministered questionnaire of 12 questions with multiple choice questions was prepared to obtain information about knowledge, attitude, and practice toward various impression techniques for dental implants. A total of 100 people involving 50 dental students and 50 dental practitioners were chosen as the participants. The responses from all students were collected as soon as they filled the questionnaire that had been distributed. The questionnaires were distributed manually to them. Statistical analysis was done using G power analysis method. Result: The specific sample study on dental students was a poor reflection when compared to dental practitioners in terms of knowledge, attitude, and practice on various impression techniques for dental implant patients. A total of 50 undergraduate dental students and 50 dental practitioners participated in this current study. Conclusion: Getting a highly stable and retentive implant had always been a problem associated for most of the prosthodontists. Proper tray selection, proper implant angulation, proper impression techniques, and coping modification are the factors that might influence the accuracy of the dental implants. Therefore, it should be considered carefully before this procedure had been started. KEY WORDS: Basis, Dental implants, Impression, Techniques
INTRODUCTION Nowadays, millions of people tend to lose their teeth. It can be due to many causes such as decay, gum disease, wear and tear, or trauma. Loss of teeth can be quiet emotional experience since it may affect our ability to speak and masticate food. Replacement of teeth will be more challenging as more number of teeth is missing. In the past, clinicians and patients had been struggling with options available to replace the missing teeth until dental implant treatment had been discovered. Treatment options for replacement of missing teeth have been evolved from acrylic dentures to metal framework and removable partial dentures to Access this article online Website: jprsolutions.info
ISSN: 0975-7619
fixed partial dentures. Actually, dental implants have been an optional treatment for dental prosthesis since late 1930, and the popularity of this treatment start to increase when the concept of osseointegration had been introduced in dentistry.[1-5] This concept had been introduced by Toronto implant in the 1980s to the North American dental community.[6-9] Based on statistic, it was revealed that approximately 100,000–300,000 dental implants are placed per year.[10] Sometimes, failure still can occur even though predictable longterm result can be obtained with implant treatment. This may be due to certain condition such as imprecise surgical or prosthodontics techniques. Based on glossary prosthodontics term, dental impression can be defined as the “negative imprint of an oral structure used to produce a positive replica of the structure which is used either for permanent record or production of dental restoration.”[11] An accurate
Department of Prosthodontics, Saveetha Dental College and Hospital, Saveetha University, Chennai, Tamil Nadu, India, Department of Prosthodontics, Saveetha Dental College and Hospital, Saveetha University, Chennai, Tamil Nadu, India
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*Corresponding author: Ashish R. Jain, Department of Prosthodontics, Saveetha Dental College and Hospital, Saveetha University, Chennai, Tamil Nadu, India. Phone: +91-9884233423. E-mail:
[email protected] Received on: 28-01-2017, Revised on: 25-02-2018, Accepted on: 14-04-2018 Drug Invention Today | Vol 10 • Issue 5 • 2018
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impression is compulsory to prevent prosthesis misfit. Prosthesis misfit can lead to some mechanical problems such as screw loosening, screw fracture, implant fracture, and occlusal inaccuracy.[12-14] Passive fit of the prosthesis and osseointegration is the factors responsible for the success of implants.[15-17] The most important steps in achieving passive fit are during impression taking. Selection of proper tray, proper impression techniques, type of impression material, and angulation of impression may influence the accuracy of dental implants.[18-24] There are numerous impression techniques available for dental implants. The techniques can be divided into two major groups which are known as direct impression techniques and indirect impression techniques. Direct impression techniques include open tray or known as pick up techniques, whereas indirect impression techniques involve closed tray and snap fit plastic impression coping. Open tray technique or known as pick up technique includes making an impression coping to the implant together with screw that projects above the height of the coping and customized impression tray which has
an opening cut on it. When the impression material has been set, the screw will be loosened, and the tray will be removed from patient’s mouth together with the impression coping remained within the impression. Later, an implant analog is tightened to the impression coping with the same screw and working cast is poured.[25,26] This technique enables the impression coping to retain in the impression. Therefore, it will prevent implant angulation, deformation toward impression material on recovery of the mouth, and to eliminate the concern for the placement of the coping back to its specific space in the impression. Some drawbacks of this technique are more parts need to be controlled during tightening, some rotational movement of the impression coping will be presence when securing the implant analog, and blind attachment of the implant analog to the impression coping may cause misfit problem. Some clinical conditions or situations may require the use of closed tray technique instead of open tray technique. For example, when the patient has limited interarch space, probability to gag, or when it is too challenging to access an implant located in the posterior area of
Figure 1: Sample size calculation
Figure 2: Percentage of results On various factors involved in accuracy of implant impression.
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Table 1: The questionnaire for the current research Number of question 1. The accuracy of implant impression depends on? a. Tray selection, b. Implant angulation c. Impression technique d. Coping modification e. All of the above 2. Are you aware of various impression techniques available for dental implants? a. Yes b. No 3. Are you aware that open tray and closed tray techniques can be applied during impression making for dental implants? a. Yes b. No 4. For multiple implants what is choice of your impression technique? a. Open tray b. Closed tray 5. Which impression material would you prefer in case of multiple non‑parallel implants? a. Vinyl polysiloxanes b. Polyether rubber base c. Alginate impression d. Condensation silicone 6. Which is the most commonly used impression materials in implant dentistry? a. Vinyl polysiloxanes b. Polyether rubber base c. Alginate impression d. Condensation silicone 7. Based on your experiences, misfit is common in which type of impression techniques? a. Open tray technique. b. Closed tray technique c. Both 8. Which components you will not use for single tooth restoration in impression procedure? a. Ball‑top screw b. Straight abutment for cement ‑ hexed c. Direct transfer coping screw d. One piece abutment for cement ‑ non‑hexed 9. Are you familiar with snap fit plastic impression coping technique? a. Yes b. No 10. During open tray impression technique, what would you prefer? a. Splinting the copings with GC pattern resin b. Splinting with acrylic resin c. Splinting with impression plaster d. Splinting with composite resin e. Non‑splinting technique 11.Complication of misfit is more toward? a. Biological b. Mechanical c. Both 12. Which is the most often implant impression technique preferred? a. Implant level b. Abutment level c. Digital impressions
the oral cavity.[27] Close tray technique involves the use of single piece impression coping which attached intraorally toward the implant when the impression is removed from patients mouth. Then, this coping is removed from implant, fixed to the implant analog, and repositioned to the impression with correct orientation. According to research done by Daoudi et al.,[28] he found that open tray technique at the implant level is more superior and more predictable when compared to closed tray technique which is at the Drug Invention Today | Vol 10 • Issue 5 • 2018
abutment level for single tooth implants. Commonly, closed tray technique will have discrepancies in terms of axial rotation and inclination of the analogs. Based on the previous study by Rodney et al., the results showed that a passive prosthesis could not be achieved either by pick up or transfer technique, but the pick up technique will establish better and accurate impression rather than transfer technique. In 1992, a two implant model with an anterior implant parallel to the adjacent natural tooth and a posterior implant 613
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exhibiting 15° lingual inclination. The accuracy of pick up and transfer technique was investigated using polyether impression material. The results suggested that the pick up technique showed comparable or better results than the transfer technique. Based on the previous study also, distortion of abutment positions was very frequent with available impression techniques. Method that is usually used to prevent this problem is using splinting of implant transfer copings to gain stabilization against rotation during analog tightening and control transfer coping relationships in the impression material. According to the study done by Branemark in 1985, he emphasized about the importance of impression copings splinted associated with dental floss scaffolding covered by autopolymerizing acrylic resin for close tray technique. The reason behind this condition was to relate the impression coping altogether using a rigid material to prevent individual coping movement during impression making procedure. Most of the previous studies suggest that implant impression with splint technique is more accurate compared to the non-split
technique alone.[29] Some authors also suggested that some problems or issues will arise when using splint techniques such as distortion of splint materials[30] and fracture of the connection between splint material and impress copings.[31] In addition, literature shows that impression copings with different kind of design provided a different level of impression accuracy. Different types of techniques had been applied such as roughening of the external surface of the coping, applying adhesive coating, different shapes, and materials were utilized to fabricate the copings. These modifications were done to produce a firmer connection between the impression coping and the impression materials which will reduce the amount of movement of the coping inside the material from impression making to produce master cast. On the other hand, improvement in implant prosthodontics leads to more enhance impression technique which is known as digital implant impression. It is in the form of computer-aided design and computer-aided manufacturing to build the implant prosthesis. This kind of technology uses 3D intraoral scanners which
Figure 3: Percentage of results On Awareness of various impression techniques available for dental implants
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Figure 4: Percentage of results On Awareness of open tray and closed tray techniques
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mimic the manual impression techniques. Furthermore, it has been proven that it is a good alternative for the analog impression taking technique. Considering the concerns mentioned above, this study was conducted with the purpose to investigate the knowledge, attitude, and practice of various impression techniques used among dental students and dental practitioner for dental implants.
MATERIALS AND METHODS A self-administered questionnaire of 12 questions with multiple choice questions was prepared, and piloting was done to obtain information about knowledge, attitude, and practice toward various impression techniques for dental implants [Table 1]. The sample size of this questionnaire-based study is 150 [Figure 1]. This was conducted with 100 participants, thus it is sufficient for the required sample size. After collection of data had been done, it was analyzed using Microsoft Excel 2007 and presented into graph.
RESULT The specific sample study on dental students is a poor reflection when compared to dental practitioners in terms of knowledge, attitude, and practice on various impression techniques for dental implant patients. A total of 50 undergraduate dental students and 50 dental practitioners participated in this current study. The questionnaires survey for undergraduate dental students was distributed randomly among 3rd year, final year, and intern students. Regarding factors influencing the accuracy of dental implants, most of the dental students (34%) and dental practitioners (62%) had the knowledge that selection of proper tray, proper implant angulation, proper impression techniques, and coping modification are the major factors that need to be considered for
successful dental implants [Figure 2]. According to the results, majority of the dental students (76%) were not aware about the various impression techniques available for dental implants, but it is quiet opposite with the dental practitioners. A percentage of 82% among dental practitioners had a great knowledge on various impression techniques available for dental implants [Figure 3]. Open tray and closed tray as the options available for impression techniques for dental implants were compared between dental students and dental practitioners; statistically highly significant difference of percentage can be observed. The percentage for dental practitioners having “yes” as the answer for this question is approximately 56%, whereas percentage for dental students having “yes” as the answer for this question is 44% only [Figure 4]. Based on Figure 5, it had been showed that a percentage of 38% of dental students stated that open tray as their choice for impression technique while 62% of dental practitioners stated that closed tray impression technique as their choice for multiple implants. In response to the question on which impression materials will be used in case of multiple nonparallel implants and the most commonly preferable impression materials for dental implants, majority of dental students and dental practitioners preferred vinyl polysiloxane rather than other impression materials such as polyether rubber base, alginate impression, and condensation silicone [Figure 6]. According to Figure 7, both dental students and dental practitioners had the same percentage for vinyl polysiloxane. However, polyether rubber bases had highest percentage (54%) among other available options such as vinyl polysiloxane, alginate impression material, and condensation silicone.
Figure 5: Percentage of results On choice if impression technique for multiple implants
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Figure 6: Percentage of results On choice of impression material for parallel and non parallel implants
students
Figure 7: Percentage of results On most commomly used impression material used for implant dentistry.
Figure 8: Percentage of results On Misfit and impression techniques.
When dental students and dental practitioners had been asked whether misfit is common in open tray or closed tray technique or both, majority dental students (42%) stated that it was common in both techniques which are significantly different with dental practitioners’ opinion. For dental practitioners, a percentage of 64% gave agreement that misfit was commonly associated with open tray technique rather than closed tray technique [Figure 8]. 616
According to Figure 5, majority of dental practitioners with a percentage of 34% stated that one piece abutment for cement non-hexed will not be used for single tooth restoration in impression procedure, whereas majority of the dental students stated that direct transfer coping was the one that will not be used for single tooth restoration in impression procedure [Figure 9]. Drug Invention Today | Vol 10 • Issue 5 • 2018
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Figure 9: Percentage of results On components used for single tooth restoration in dental implant procedures.
Figure 10: Percentage of results On Awareness about snap fit plastic impression copings.
Based on the result, most of the dental practitioners with a percentage of 80% familiar with snap fit plastic impression coping technique, whereas only 20% of the dental students familiar with it. 64% of dental students were still unaware about snap fit plastic impression technique [Figure 10]. According to Figure 11, most of the dental students (30%) intended splinting with impression plaster during open tray technique, whereas most of the dental practitioners (34%) prefer splinting with acrylic resin during open tray impression technique. According to the result, dental students with a percentage of 48% stated that complication of misfit is more toward both biological and mechanical, whereas most of the dental practitioners stated that misfit is more toward both biological and mechanical with a percentage of 48% [Figure 12]. Based on question no 12, digital impression was the most often implant impression technique preferred by vast community of dental students in this current study with a percentage of 60%, whereas dental practitioners stated that implant level was the most preferable impression for dental implant patients with a percentage of 44%.
DISCUSSION Implant cast accuracy influences by many factors such Drug Invention Today | Vol 10 • Issue 5 • 2018
as type of impression material, implant impression technique, the implant angulation, stone accuracy, and master cast technique. The major goal for all these things is to establish a prosthesis that can seats passively onto the implants. The present study gives us an overview regarding the knowledge, attitude, and practice of various impression techniques available for dental implants among dental students and dental practitioners. According to the current study, it was reported that dental students had lower level of awareness regarding various impression techniques available compared to dental practitioners. In our opinion, the difference of this awareness could be contributed by the fact that they have a lower level of education compared to the dental practitioners. Yet, some of them still exposing or just exposed with clinical years. Among the participants who are familiar with snap fit plastic impression technique, only 24% of dental students give a positive response, whereas 64% of dental practitioners are familiar with this technique. In my opinion, this is maybe because dental practitioners had more clinical experiences compared to dental students. Therefore, they are more familiar with this technique. Other than that it had been showed also that most of the dental practitioners (54%) used polyether rubber base material rather than other impression materials such as condensation silicone, alginate impression, 617
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Figure 11: Percentage of results On type of splinting materials used during open tray impression technique.
Figure 12: Percentage of results On biological and mechanical misfit complications.
and vinyl polysiloxane, whereas dental students with a percentage of 30% preferred vinyl polyxane impression material the most during impression taking in implant procedure. There were many studies had been done to examine the accuracy of the impression materials for implant, and it was found that a study conducted by Spector et al. had similar pattern of result in which 52% of postgraduate preferred polyether the most than undergraduate which had a percentage of 32% for polyether rubber base materials.[30] The important features for an impression material are that it should have good wettability. The wettability property will actually help in obtain detail reproduction in wet oral surfaces and also established the details properly with gypsum slurry.[32] Vinyl polysiloxane which is a hydrophobic impression material has been changed to hydrophilic like polyether by adding extrinsic surfactants. 618
Therefore, it also increases it wettability property.[33-36] However, polyether rubber base material still has its own limitation, especially when it is used for patients having undercut. On the other hand, most of the dental students (30%) intended splinting with impression plaster during open tray technique, whereas most of the dental practitioners (34%) prefer splinting with acrylic resin during open tray impression technique. It was reported that a study conducted by Cabral and Guedes also had the same result in which 40% of dental practitioners used splinting with acrylic resin during open tray techniques.[32] They also mentioned that splinting with acrylic resin will lead to better accuracy of impression compared to other techniques. In our opinion, the fact that dental students do not prefer splinting with acrylic resin maybe because it is a sensitive technique and requires a lot of skills to get better result when using it. Based on Figure 5, there Drug Invention Today | Vol 10 • Issue 5 • 2018
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Figure 13: Percentage of results On biological and mechanical misfit complications.
was a contraindication between impressions used for multiple implants. Most of dental students preferred closed tray the most while high percentage of dental practitioners gave the opposite choice which was open tray impression technique. Based on the previous studies by Doudi et al., 46% percent of postgraduate intended open tray technique rather than closed tray during impression of implants. The repositioning of coping was done after making transfer impression among three different groups which were senior dentists, postgraduate dental students, and dental technicians. The result showed that all the copings were not returned to their actual location, and this was believed to the main source of error in the closed tray technique impression technique. This error also could be increased, especially in multiple implants.[28] Attitude toward the application of various impression techniques slightly differs between dental students and dental practitioners. High percentage of dental students prefers digital impression instead of abutment level or implant level for implant impression technique. This was maybe due to increase the level of patients’ acceptance, reduce distortion of impression materials, previsualization of the implant prosthetic space, cost, and time effectiveness.[37] In our opinion also, since it is slightly impossible to master all impression techniques available for dental implants; therefore, the clinical choice of impression based on personal preference is accepted.
CONCLUSION Getting a highly stable and retentive implant has always been a problem associated for most of the prosthodontists. Proper tray selection, proper implant angulation, proper impression techniques, and coping Drug Invention Today | Vol 10 • Issue 5 • 2018
modification are the factors that may influence the accuracy of the dental implants. Therefore, it should be considered carefully before this procedure has been started. It also showed the need for providing more information and knowledge about impression techniques available for dental implants among dental students. Hence, proper dental education with an interesting way of delivering is necessary to develop a positive attitude among dental student population toward dental implants holistically.
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Source of support: Nil; Conflict of interest: None Declared
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