Factors Affecting Root Canal Success

Introduction

The long-term prognosis and survival of root canal treatment is reliant on multiple factors, from case selection, use of rubber dam, adequate access opening, finding all canals and accessory canals, glide path, chemo mechanical preparation and to final restoration. The quality of root canal influences the prognosis of root canal treatment. Root canal treatment is generally viewed as “dark art” by GDPS (general dental practitioners) as most done in general practice without adequate magnification, on least motivated patients with time constraints and low renumeration. Added to the issues are of it being complex procedure and time consuming. The standard of Root canal treatments offered by general dentists depends largely on the undergraduate teaching at dental school, where most of their skills were formed. The way undergraduates are taught in the dental school varies all over the world and hence the standard of root canal treatments performed by different dentists varies as well. (A.Baaji and A.R.Ozaik 2017). Research has shown that some methods of teaching under graduates yield better outcomes than others, supervised clinical teaching seems to be better than unsupervised and direct supervision under endodontics has better chances of success when compared to direct supervision under a general dentist (A.Baaji and A.R.Ozaik). The dental schools in the UK all follow the “preparing to practice” document of the general dental council while teaching and training endodontics to the undergraduate dental students (J. Davey ,S. T. Bryant ,P. M. H. Dummer.2014) Despite the guidelines, numerous articles have found out the quality of the majority of root canals performed by undergraduates has been unacceptable, ranging from 87% to 55% unacceptable. Conversely, several studies have shown acceptable root canal fillings in undergraduate students 70-80%. This shows that undergraduate students are capable to performing root canal treatments of high standards and the difference in the ranges may seem to be in quality of undergraduate education they are receiving. J. P. Tchorz ,M. Brandl .P. A. Ganter ,L. Karygianni ,O. Polydorou ,K. Vach ,E.Hellwig M. J. Altenburger(2014) compared the differences between training undergraduates on human teeth and artificial teeth. They found that there is no effect on the technical quality of the filled root canals when both the cohorts start practising on live patients. The researchers argued that since as undergraduates are carrying out their first root canal artificial teeth may be better in terms of simple root anatomy and the results are comparable and can be measured. Although, students using human teeth need more teeth due to iatrogenic factors compared to students who used plastic teeth, the radiographic evaluation also yielded better results in artificial teeth than in students using plastic teeth. The results are arguable as human teeth have more complex anatomy and artificial teeth are simpler in comparison , practising on human teeth will give the undergraduate more realistic experience before actually carrying out the treatment on patients. On the other hand there has been a lot of advances in artificial endo teeth and now there is an availability of more complex anatomy, and they don’t have to be sterilized or disinfected before use .

What makes dentists take postgraduate training in a particular field? Research suggests encouragement from family members, partners and staff to be one of the reasons. One of the key factors was found to be the undergraduate experience which the student had or “having a talent in the field” was another factor found in UK dentists which had been a source of influence leading them to follow postgraduate training. (James Puryer, Joanna Selby, Joshua Layton, Jonathan Sandy and Anthony Ireland .2017) Fine P, Leung A, Bentall C, Louca C. (2019) stated that post graduate training has a direct effect on the confidence of the practitioner and hence lack of confidence is one of factors why general dentist undertake postgraduate training. Increase in confidence is by the dentist feeling competent in the field and its means better communication with the patient and better uptake of treatment which leads to job satisfaction. Other reasons are keeping up to date with skills and keeping up to date with continuing professional development requirement as set out by the general dental council. (Puryer et al .2017)

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Literature review

Literature review shows the readers that the writer has a firm grasp on the knowledge in the field and that the writer understands where their own research stands and adds to in the existing body of knowledge. It is a process that one reaches after a thorough and in depth analyses of the current evidence present in the particle field of study, summarises the prior research and identifies the gaps in the current knowledge .points in the direction of the new point for research and why it is undertaken (royal literary fund)

The following keywords were used for a search of each database:

Survival of root canal treatment

General dentist and/or root canal

Root canal failure

The following exclusion criteria were applied:

• Articles must have been published within the last 10 years

• Articles must be written in the English language

• Articles limited to journal articles only

The research carried out in the northwest of England by (M. Tickle, K. Milsom, A. Qualtrough, F. Blinkhorn and V. R. Aggarwal) aimed to find out the quality of root canal performed by the GDP but their results cannot be generalized to the whole of UK population of GDPs because of limited to a small area (Salford) and small sample size of 174 molar treated teeth. The study did endorse a very important conclusion, that fate of the root canal treatment depends on the final restoration but it did not outline the added skills or qualifications of GDPs preforming the Root Canal treatments. A survey conducted to measure the level of confidence in dentists before post graduate qualification courses could be concluded and after postgraduate qualification degree course could come to the closue was very interesting as the dentists reported an increase in confidence and skills after the five year post graduate qualification and also the increase in treatments offered to the patients (Peter Fine, Chris Louca and Albert Leung 2017).Although interesting, restorative postgraduate qualification was not limited to root canal treatment only and sample size 72 of which only 20% completed their masters . A study in Sweden compared the effect of Root Canal success in primary care setting before and after post graduate training (M.Koch, E.Wolf, A.Tegelburg and K Petersson 2015). Although there was an increase in the quality of root canal and survival rate, however, there was no improvement in the apical status. .There is a lot of limitations in the study. For example the study only involved sample from a small region, so it is doubtful if the study could be generalised properly. Secondly, the participants were trained in NITIR (nickel titanium rotary instrument)with single cone technique but no details about irrigation protocol was communicated, it does mention that the irrigation protocol remained the same and hence this could be the reason of the no change in apical status since we can’t be sure if the bacteria were completely eradicated. Also there was a 7 year preoperative and 4 year follow up of radiographs ,so the more time given for pre postgraduate education radiographs hence more time for apical lesions to heal. Finally, 11% of the cohort continued to use stainless steel instruments even after the training. So the results cannot be a true representation of the actual situation .

Another Swedish study concerning the general perception and level of difficulty faced by the general dental practitioners was performed by L. Dahlström O. Lindwall H. Rystedt C. Reit (2016) .The study design was qualitative and an expected result of feelings of frustration and anxiety while performing root canal treatments. The study sample was from a specific place in Sweden, Gothenburg. Could the results be generalized to all the Swedish Dentist? The study only used general practitioners employed by the public dental health service but did not include GDPs working privately. The GDPs from the same area where also part of three more studies. The question was why had this been an occurrence. The study did not disclose any new information regarding general dentist and root canal treatment and was not designed to include questions which could help to implement changes in the system. A Qualitative study design was carried out in London (S. Eliyas ,P. Briggs and J. E. Gallagher 2016) with text questionnaires. It involved 8 dentists, small sample size? 24 month programme ,so they are not including the generic NHS type dentists who may not have the time or resources to commit to such a study programme ,the study includes very motivated dentists who are willing to commit to such a study programme as they were selected through a series of competitive interview process and were already actively seeking postgraduate training. The study’s limitation may also be the utilisation of only textual questioners, involving two or more methods may have given them a deeper insight. The new study would be a mixed study, including quantitative and qualitative, including feelings and experiences and data from the survey. It will include generic NHS dentist who have undergone any kind of postgraduate day course or training programme in endodontics in order to develop their endodontic skill with primary aim to consistently provide better quality root canal treatments on the national health service. The study will strive to have a larger sample size from across England so that a wider view can be obtained. Sample size will be generated with the help of computer software. To ensure that the response is large, it will be done through postal prepaid stamp and an incentive (prize draw) will be given to the participants. In addition to this, interviews and questionnaires will also be done through study clubs. A study like this hasn’t be conducted in England, there are similar studies which either ask the same question but not in endodontics or in endodontics but not conducted in England.

Aim

The aim of this study is to understand the difficulties faced by the general practitioners in the United Kingdom during the root canal treatments and the effect of postgraduate qualifications on the success of root canal treatments. The study has educational value as well, as it can help to understand the gaps in knowledge /teaching at undergraduate level. This in turn can help to shape the curriculum of undergraduate dental schools in United Kingdom.

Hypothesis

Hypothesis is a explanation or an idea given, for a phenomenon based on limited evidence before the study is carried out .it is the starting point of investigation. (oxford dictionary)

Null hypothesis

There will be a positive result after postgraduate training, in the level of confidence of general dental practitioners and the quantity of Root canal treatments

Alternative hypothesis

There will not be any change after postgraduate training in the confidence and quantity of Root canal treatments

Methodology

A mixed design study is chosen for this research involving both qualitative and quantitative methods. To gain a maximum depth of knowledge, it is felt that choosing only one method would not be sufficient. Quantitative methods involve survey questions, the questions are assembled based on the research questions and from some of the samples which are derived from similar studies. Qualitative studies involve again with 1) surveys (open ended questions) 2) interviews and 3) focus group discussions. All the qualitative data accumulated can be arranged according to the common recurring themes that emerge through the interviews. The mechanism employed to reduce bias and increase reliability can be by follow a structured set of questions used during interviews and focus group meetings. The structured set of questions can be developed by looking at the results from the surveys conducted (Peter Fine et al.2017) This study will be cross sectional, observational study ,which means it will concentrate on a particular group within a specific time frame.

Sampling

Sampling means selecting or choosing units (e.g. people) from a representative population, so that in the end the results can be applied to the entire population from which the sample had been derived. There are two ways in which sampling can be done, Random sampling and Non-random sampling. We are going to use non random sampling technique as it increases the internal validity. Random sampling means every individual in the population has equal chance of being included in the sample (Fox N. Hunn A. Mathers N. 2009). There are three ways this is done simple random sampling, non-random sampling and systematic random sampling (mixed sampling) .This study will use random sampling for all general dentist registered on the general dental council website . Sample size calculation in quantitative study design can be done by consulting a statistician or alternatively a number of different software (e.g. survey monkey, creative research systems) in order to get an idea how many responses should we get, a table of randomly generated numbers or the fish bowl draw(if the total population is small) ,to get the result that can be reflected to the target population before starting a study. (Ranjit Kumar 2014) Sample size calculation in qualitative design is not as important as it is in qualitative design ,as the aim is to interview the people who are assessed to give the maximum insight into a particular situation . Most scientific surveys use a confidence level (how confident we can be of our results) of 95% and confidence interval(the degree of precision we can accept) of +/- 5%.

Reliability and credibility

Validity means how well a variable measures what it is supposed to, it is important in descriptive studies. It is important to establish the quality of and accuracy of the results achieved during the research, as inaccuracies can be introduced at any stage. Broadly, there are two parts in validity. First is the research answering question which it was designed to do. The second, whether the the method untaken to find the answer has been appropriate. It is primarily on the researcher to make sure that there could be a direct link between the questions asked and the research which can be difficult as the research may see the link and others may not. It is difficult in situations where the effectiveness, satisfaction (feelings)are measured, but, in situations, where there is a scale against which the findings can be compared, then the greater the comparability could be the greater the validity would be as well. Reliability is a word often used in our everyday lives, it means dependable, predictable and consistent. In research it has the same meaning, consistency in method/ measuring, can it be repeated? In developing the survey questions the set of question mentioned in appendix 2 ,should give the same result in similar population, without any time lag ,under similar conditions .If the result have greater difference it will mean that the questionnaire is unreliable and lesser the difference means more reliable .(Ranjit Kumar 2014)

Data collection

Data collection in qualitative study is performed through interviews, focus groups, oral histories, case studies and observations and data is collected in quantitative studies through questionnaires, surveys, interviews and statistical analyses. The tools could still be the same but how the data was collected. analysed and how findings were communicated determines the difference between qualitative and quantitative study. (Ranjit Kumar 2014) Interviews can be either structured or unstructured. Structured interviews are usually quantitative where a set of structured and close ended questions are developed and the study design chosen is mixed design study. On the other hand, the qualitative data collection method will consist of unstructured interviews of the sample population. Due to the large geographical distribution of the study population (England) this may prove to be an expensive method. Postal self-completion questionnaires provide an efficient and least expensive method of data collection in health care research, different strategies have been proposed to increase the response rate. A major disadvantage with postal questionnaires is lack of or low response rate leading to bias. Rachel A Nakas, Jane L Hutton, Ellen C Jørstad-Stein, Simon Gates and Sarah E Lamb(2006) found that reminders in the form of letters, telephone contact and short length of the survey seemed to increase the response rate and incentives did not have any effect on the response rate. (Wilson PM, Petticrew M, Calnan M, Nazareth I 2010). However, there are other studies which support the theory that incentives do increase the response rate. Before a questionnaire is developed, the areas which are aimed to be investigated by the research questionnaire are first measured and the outcomes of such measurement are to be stated in unequivocal terms. This will help with the data coding once the questionnaire is returned. If there is already a questionnaire present in the similar trial then it helps to use or include the questions as the results can be comparable. If a new questionnaire is to be developed then testing will determine what could be required to be measured. It is also helpful if the ease of reading of the questions is checked by using the flesch reading ease score ,higher score means the material is easy to read.

The questionnaire design can include open ended and close ended questions ,open ended questions are helpful when there are a large number of answers and the aim is to capture all of the relatable answers in detail .Sufficient space is provided to the participants so that they can write all the intended answers .Close ended questions include either “yes or no “answers or “tick all that apply “ , furthermore, questions can be further branched off by asking participants more about their choices of the questions. Design, order and layout are important as well, these include verbal and nonverbal language used (symbol, graphical features). Self-administered questionnaire is cost effective as these don’t require any input form the interviewer apart from the distribution. Postal questionnaire require getting accurate postal address and the cost of distributing them has to be kept in mind. Emailed questionnaires require accurate email addresses and access to computers and internet. questionnaires are helpful as they give the participants time to think about their responses, since they have least input from the investigator hence is less susceptible to information bias but more susceptible to non-response. evidence from systematic review of studies shows questionnaire to be more reliable than interviews. However carefully the questionnaire is designed, it’s very likely that there will always be a few respondents who will not answer (Phil Edward 2010). The data collection method will be questionnaire with pre-paid postage label to random selected general dentist working in England registered with the GDC. In order to make sure we have a large sample size, questionnaire will also be distributed in study clubs e.g. Dentinal tubules, local regional BDA study club. Advantages of choosing this method are less expensive and greater anonymity.

Data analyses

The purpose of data analyses is to draw conclusions from the research. Quantitative data can be analysed using SPSS software version 21 (IBM SPSS, London, UK) and the derived results will be calculated with the help of a statistician .For the quantitative part of the study, descriptive statistics will be used to analyse the data . Qualitative data from interviews, focus groups and field notes can be analysed using a phenomenological approach, after having organised the data thematically via a “Framework” spreadsheet.

Pilot study

Piloting is a process whereby the questions are first tested before being used in the tria. .The questions are first sent to the researchers who have some knowledge and experience about the subject to comment on the questions. .The questions are is then revised and then be piloted in a non-expert group such as colleagues. .A further revised draft is then used in a sample population of people who will complete the questionnaire in the actual trial(Edward phil 2010)

Conclusion

There seem to be a lot of post graduate training courses available in the market today, one does question why would the graduates of schools from the United Kingdom and working in general practices would need to attend these courses if they were already trained in state-of-the-art facilities? If one observes different graduates from the dental schools in England there does seem to be differences in the way that they were trained, some training being superior to other. Added to this mix are overseas dentists who have passed their licensing exams but were trained entirely differently. What happens if a deficiency has been identified in a dentist or the dentists themselves identify a problem in their practice while having to perform self-reflection? Do post graduate courses or study days really have an effect in confidence and treatment uptake why do most dentist avoid root canal treatments on the national health service ?is it the unfair renumeration or really the lack of skills developed during undergraduate training . The study will answer a lot of questions relating to undergraduate and post graduate training, which will prove to be beneficial for understanding the needs of dentist.

Dissemination

This study will be used as my dissertation for my MSc in Endodontology at the University of Chester. I would like to publish the completed study in a scientific journal such as the Journal of Endodontics. There is an ethical responsibility for researchers to allow their findings to be transparent, accessible and open to the scrutiny of the scientific community (World Medical Association 2013).