Frequency and distribution of maxillary teeth treated by a single visit and multiple visit endodontics in an Indian population – A retrospective study

Controversy exists as to the completion of endodontic procedures in a single visit or in multiple visits. Analyzing the frequency and distribution of single andmultiple visit endodontics carriedout basedondemographic data cangive us an insight towards the success of the treatment. This retrospective study aimed to analyse the frequency and distribution of maxillary teeth treated by single or multiple visit endodontics in an Indian population. Data for the study were collected retrospectively. Patient records of 86000 patients that reported to the institutionbetween June2019andMarch2020were reviewed. Excel sheet tabulations were made involving age, gender, tooth number and number of visits. Descriptive statistics were applied using SPSS software. Associationbetweeneachdemographic data and thenumberof visitswas analyzed by Chi-Square Test. A total of 4493 RCT procedures were done, of which 48.6% were single visit procedures and 51.4% were multi-visit procedures. The age groupof 18-30years (31.7%)and31-40years (29.3%)underwent the highest number of procedures, followed by 41-50 years (21%) and >50 years (18%). 51%0f the procedureswere done inmales and 49% in females. Statistically, a signi icant association was observed between age, gender and tooth with a type of treatment (single or multiple visit endodontics), p<0.05. A statistically signi icant association between age, gender and tooth was observed with the type of treatment (single and multiple visit endodontics). Younger age group, males and maxillary central incisors showed the highest predilection to multi-visit endodontics. In general, more multi-visit procedures than single visit procedures were done in maxillary teeth.


INTRODUCTION
The main objective of endodontic therapy is the complete debridement of necrotic and infectious tissue and disinfection of the root canal system (Gutmann, 1992), followed by a three-dimensional seal to prevent re-entry of microorganisms. Contemporary endodontics must adhere to the certain principles which are based on the previous principles formulated in the past (Grossman, 1967). These include: 1) use of the aseptic technique; (Rani et al., 2016) 2) cleaning the canals thoroughly and mechanically with the aid of chemical agents; 3) shaping the root canals for ease of obturation; 4) obturation to achieve a tight seal of the root canals; and 5) proper restoration of the tooth to prevent coronal leakage, which can induce future bacterial reinfection.
Today, endodontics aims at cleaning and disinfecting more than mechanical shaping of the canals (Teja and Ramesh, 2019). The ifth objective, which is the maintenance of a good coronal seal followed by an appropriate post endodontic restoration, is often neglected. Nowadays, composite materials are very commonly used for this purpose. Various studies have been done to assess the bond strength and fracture resistance of these materials for the evaluation of long term success (Hussainy, 2018).
Nowadays, the concept of prevention of extension has led to a more conservative approach to post endodontic restorations. Veneers and laminates can be used in anterior teeth in place of fullcoverage crowns. Recent advances in these techniques improve esthetics and ef iciency of the operator (Ravinthar and Jayalakshmi, 2018). Endodontic treatment, in the past, took multiple visits to complete, with one of the main reasons for this being the lack of technology which necessitated a considerable amount of time to complete every step throughout the treatment (Mohammadi et al., 2006).
The use of contemporary endodontic techniques and equipment, beginning with advanced diagnostic techniques (Janani et al., 2020) such as the use of rubber dam, magnifying devices, electronic apex locators, engine-driven rotary nickel-titanium iles (Ramanathan and Solete, 2015), and so forth, not only increases the success rate of endodontic treatment but also, shortens the time needed for the treatment. This led to the current concept of 'single visit endodontics' which is routinely practised today. Our team has performed various researches on various materials and instruments used in endodontics (Manohar and Sharma, 2018;Nasim and Nandakumar, 2018;Ramesh et al., 2018). (Siddique, 2019) We have also done various in vitro, in vivo experiments as well as clinical trials on other topics in restorative dentistry and endodontics. (Ramamoorthi et al., 2015;Noor and Pradeep, 2016).
The concept of a single-visit root canal treatment was described as early as the 1880s. The treatment techniques used at that time were very primitive, and the success rate of single-visit root canal treatment was low, which led to a decline in the use of this approach. The single-visit treatment was bought back in the 1950s by Ferranti et al. (Ferranti, 1959), who advocated the use of diathermy for pulpal disinfection and hydrogen peroxide for irri-gation. Although today the techniques of practice are signi icantly different, the basic principles are the same as used by Ferranti. Nowadays, root canal therapy has become increasingly automated and can be performed more quickly, so some clinicians are incorporating single-visit endodontics into their own clinic routine as the main component of contemporary practice. On the other hand, some dentists believe that the traditional multiple-visit protocol has a long history and a high clinical success rate, preferring to provide multiple-visit endodontic treatment to their patients.
Considerable controversy exists regarding whether it is preferable to complete endodontic therapy in one or multiple appointments. The factors to be considered in the choice of the type of treatment are operator ability and clinical experience, tooth conditions (vitality, presence of symptoms, swelling), adequate treatment time, patient's time constraints, medical history, as well as anatomic considerations (Figini et al., 2008).
Maxillary bone is known to be porous in nature as compared to the dense mandibular bone (Abrahams et al., 1995). This may be one of the reasons why the spread of infection in the maxilla is faster as compared to the mandible. This makes the need for a more prompt diagnosis and treatment for diseased maxillary teeth. The decision of treating maxillary teeth in a single visit or multiple visits must be taken carefully.
Studying the frequency and distribution of teeth treated by these two approaches will give us an insight into the success of the respective treatment modalities. Hence, the aim of this study was to analyze the distribution and frequency of maxillary teeth treated with single and multiple visit endodontics in an Indian population.

MATERIALS AND METHODS
The study was conducted in an institution online setting. One researcher, one guide and one mentor, were involved in conducting the study. Approval was obtained from the Institutional Review Board, Saveetha Dental College, Chennai. Data were collected retrospectively from patients reporting to the institute. Patient records of 86000 patients that reported to the institute from June 2019 to March 2020 were reviewed. Data of adult patients whose maxillary teeth were treated endodontically were included in the study.
Excel sheet tabulations were constructed for Age, Gender, Tooth Number and Type of treatment (single and multiple visit endodontics). Treatments are done on primary teeth and patients below 18 years of age were excluded in order to generalize the study to adult patients only.

RESULTS AND DISCUSSION
The data was imported to SPSS Software (Version 23.0) and descriptive statistics were done to analyze the distribution and frequency of single and multiple visit endodontics. A total of 4493 RCT procedures were done, of which 2183 were single visit and 2310 were multiple visit procedures [Table 1, Figure 1]. A higher number of multi-visit procedures were done as compared to single-visit procedures. The age group of 18-30 years (1421) and 31-40 years (1317) showed the highest number of procedures done. The 41-50 years age group showed 943 procedures done and >50 years age group showed 809 procedures done [Table 2, Figure 2]. Age group 18-30 years and 31-40 years showed the highest prevalence. A total of 2292 procedures were done in males and 2201 in females [Table 3, Figure 3]. An approximately, equal number of males and females were treated. Maximum procedures were done in maxillary irst molars (997 RCT procedures) followed by central incisors (821 RCT procedures) and least was done in maxillary 3 rd molars (98 RCT procedures) followed by canines (365 RCT procedures) [ Table 4, Figure 4]. The highest number of root canal treatments were done in maxillary irst molars The association between each parameter (age, gender and tooth) with the type of treatment (single or multiple visit endodontics) was analyzed by performing the Chi-Square Test. A signi icant association was observed between all three parameters and the type of treatment (p<0.05). Age group 18-30 years and 31-40 years showed a maximum number         The higher number of multi-visit RCT procedures in males than females. Maximummulti-visit procedures were performed on maxillary molars and central incisors.
of multi-visit RCT procedures. A higher number of multi-visit procedures were performed in younger age groups [Table 5, Figure 5]. Males showed a higher number of multi-visit RCTs performed. A higher number of multi-visit RCT procedures were done in males [Table 6, Figure 6]. Maxillary central incisors showed a signi icantly higher number of multi-visit root canal procedures as compared to a single visit. Maximum procedures were done in maxillary irst molars, followed by central incisors and second premolars [Table 7, Figure 7].
Single-visit endodontics is de ined as a conservative nonsurgical treatment of an endodontically involved tooth consisting of complete biomechanical cleansing, shaping, and obturation of the root canal system during one visit (Ashkenaz, 1984). Teeth indicated to be treated in single-visit include vital teeth with pulp exposures caused by trauma, caries, or mechanical reasons; teeth with subgingival break-   down; teeth with multiple coronal walls missing; full coverage restorations with carious margins; fractured anterior or bicuspids requiring temporary restorations; teeth to be used as overdenture abutments, full veneer crowns on mandibular anterior; physically disabled patients or patients who require sedation (Mohammadi et al., 2006). The main contraindications are the presence of anatomic anomalies (receded pulp chambers, calci ied canals, sharply curved canals, bifurcated canals, and dilacerations) or procedural dif iculties (broken instruments, perforations, ledge formation) that extend treatment time, patients suffering from physical (muscular dystrophy) or mental disability (neuromuscular disorders) that require good patient cooperation. Also, teeth with severe in lammation or large periapical infections are avoided. Researchers have studied and analyzed different techniques to overcome these dif iculties, most of which involve the use of multiple visits (Kumar and Antony, 2018).
In this study, out of a total of 4493 root canal procedures done, 48.6% (2183) were single visit while 51.4% (2310) were multi-visit procedures. This shows that approximately an equal number of single and multiple visit procedures are done in the institution. This inding is supported by a previous survey (Inamoto et al., 2002) which stated that root canal obturation during a irst visit was carried out by 55.8% of the endodontists. Although, in infected root canal cases, the percentage was decreased to 34.4%. The distribution of multi-visit RCT procedures being done was signi icantly higher in younger age groups, in males, and in central incisors (p<0.05). Single-visit RCT was most commonly carried out in maxillary canines.
The highest numbers of RCT procedures were carried out in the 18-30years age group (1424) with 632 single visit and 792 multi-visit RCTs and the 31-40years group (1317) with 590 single visit and 727 multi-visit procedures. This may be due to the fact that the younger age groups are more conscious about their oral health and esthetics due to which they acquire dental treatment more often than older age groups. This is supported by a previous study done by Eckerbom et al. in 1987(Eckerbom et al., 1989 which stated that the distribution of patients' age skewed towards younger age groups and can probably be explained by the fact that these age groups seek dental treatment more often than older age groups. A higher number of multi-visit RCT procedures were carried out in males (1221 multi-visit and 1071 single visit), while a higher number of single visit RCT procedures were carried out in females (1112 sin-gle visit and 1089 multi-visit procedures). This inding is contradictory to a previous study (Lorduy et al., 2018) which stated that female sex was more prevalent in endodontic procedures (68% females in undergraduate group and 70.1% females in the graduate group were treated). This may be due to the fact that smoking, which is a predisposing factor for persistent apical periodontitis (Kirkevang et al., 2007) as well as delayed wound healing (Balaji, 2008), is more prevalent in males. This may compel the clinician to opt for multi-visit procedures in these patients.
In general, the maximum number of endodontic procedures were carried out in the maxillary irst molars followed by incisors, premolars and least in canines. This is in concurrence with an article by L.L Kirkevang et al. which stated that molars have a higher risk of developing apical periodontitis than incisors and premolars (Kirkevang et al., 2007). The maxillary central incisors were reported to have a maximum number of multi-visit endodontic procedures (323 single visit and 493 multi-visit procedures). The higher number of multi-visit procedures in these teeth can be attributed to the fact that these teeth are most likely to undergo dental trauma (Andersson, 2013). Even in severely traumatized teeth like avulsed teeth, endodontics can be performed, if extraoral dry time is reduced. For this purpose, several storage media are recommended (Rajakeerthi and Nivedhitha, 2019). Traumatized teeth generally present with numerous complications like non-vitality, internal resorption, external root resorption, periapical lesions, etc. which makes it mandatory for the clinician to complete the procedure in multiple visits using intracanal medicaments such as calcium hydroxide. Simpler fractures like Ellis' Class 1 and 2 fractures usually do not require the need for endodontic treatment. A survey was conducted to assess the practice of such teeth by dentists (Jose et al., 2020).
The limitations of this study were that it was limited to a single population in a con ined geographical area. Hence, long term clinical research on this topic is required in larger geographical areas covering larger populations. A more detailed analysis of the treatment outcomes and success must be studied, especially based on the tooth and age group in order to provide appropriate guidelines for practising single and multiple visit endodontics.

CONCLUSION
Within the limitations of this study, it can be concluded that a higher number of multi-visit procedures as compared to single-visit procedures were done in maxillary teeth. There was a signi icant association between age, gender and tooth with single and multi-visit endodontics. Younger age groups, male gender, and maxillary central incisors showed the highest predilection for multi-visit root canal treatments as compared to single visit root canal treatments.