Encyclopedia
Please note this is a comparison between Version 1 by Xu Dong and Version 4 by Jason Zhu.
Bioceramics, with excellent bioactivity and biocompatibility, have been widely used in dentistry, particularly in endodontics. Mineral trioxide aggregate (MTA) is the most widely used bioceramic in endodontics. Many new bioceramics have been developed, showing good potential for the treatment of endodontic diseases.
- bioceramics
- endodontic diseases
- vital pulp therapy
- root canal therapy
- endodontic microsurgery
- regenerative endodontic treatment
1. Introduction:
ndodontics is the branch of dentistry that deals with the diagnosis and treatment of dental pulp and periapical diseases. The main objective of endodontic treatment is to preserve the natural dentition by removing the diseased pulp tissue and preventing the spread of infection to the surrounding tissues. Endodontic therapy involves the removal of the pulp tissue, cleaning, shaping, and obturating the root canal system, and restoring the tooth to its functional and esthetic state.
Clinical applications in endodontics have evolved over time, thanks to advances in technology, materials, and techniques. The field has grown beyond conventional root canal treatment to include surgical endodontics, regenerative endodontics, and vital pulp therapy. These advancements have expanded the scope of endodontic treatment, making it possible to save teeth that would have been previously deemed hopeless.
The clinical applications in endodontics are numerous and varied, ranging from the treatment of primary teeth to the management of complex cases involving retreatment, perforations, and resorption. Endodontic treatment is a fundamental component of contemporary dentistry and is essential in preserving natural teeth, preventing tooth loss, and maintaining oral health. some of the applications are as follows:
2. Root-End Filling
Root-end filling can be achieved using either orthograde or retrograde filling, both of which aim to achieve apical sealing. An ideal apical sealing material should have bioactivity, biocompatibility, long-term sealing ability, good operating performance, and the ability to promote tissue healing [1][2][3][8,68,69]. In dentistry, almost all available restorative materials have been used as root-end filling materials, and bioceramics such as MTA are among the most prominent [4][70].
21.1. Orthograde Filling
Orthograde filling generally refers to the apical barrier technique, which transports MTA or other materials from the coronal side of the root canal to the apical position to seal the apex of the tooth and provide conditions for the rigorous root canal filling [5][71]. MTA has been widely used in the apical barrier technique and has achieved long-term clinical and radiographic success [6][7][8][9][10][72,73,74,75,76]. In a case series of 5–15 years, MTA as an apical barrier for the treatment of nonvital immature teeth achieved a healing rate of 96% [11][77].
The application of other bioceramics as apical barriers has also been reported. Biodentine as an apical barrier is better at preventing bacterial leakage than MTA in vitro [12][13][78,79]. Apical barrier techniques using MTA, Biodentine, and CEM increase the fracture resistance of immature teeth [14][15][80,81]. CEM as an apical barrier material has a smaller or similar amount of leakage to MTA as determined by the fluid filtration method in vitro [16][17][18][82,83,84]. The results of the liquid filtration show that BioAggregate and white MTA apical plugs have similar leakage resistance [19][85]. In a clinical trial, the 2-year success rate of 11 teeth treated with MTA and BioAggregate was 100% [20][86].
Of note, MTA is currently the most recommended material for apical barriers, while other materials such as Biodentine, BioAggregate, and CEM require more high-quality studies to prove their effectiveness in this clinical application.
21.2. Retrograde Filling
Retrograde filling is a surgical method for the treatment of recurrent periapical lesions, to seal the root end and avoid the spread of infection in the root canal system [21][87]. Retrograde filling is performed after 3 mm of apical resection and 3 mm of root-end preparation, which is one of the most critical steps in endodontic microsurgery and intentional replantation [22][23][88,89].
Endodontic Microsurgery
Endodontic microsurgery (EMS) is an effective method for tooth preservation in patients with complicated periapical diseases. The clinical outcomes of apical surgery are inseparable from rigorous root-end filling, which is a critical step in ensuring effective apical closure to reduce microleakage and reinfection [24][90]. Bioceramics, such as MTA, are widely used in EMS because of their good biocompatibility, excellent sealing ability, inhibition of pathogenic microorganisms, and ability to promote the healing of periapical tissues [25][91]. The success rate of bioceramics is significantly higher than that of amalgam and resin materials and is similar to the use of intermediate repair materials (IRM) and super ethoxybenzoic acid (Super EBA) as root-end filling materials in apical surgery [25][26][27][91,92,93].
The success rate of 1–5 years of bioceramics as root-end filling materials in EMS is 86.4–95.6% [25][91]. MTA and Biodentine have splendid biocompatibility and apical sealing abilities, and both can promote periapical bone healing in vitro [28][29][94,95]. The use of fast-setting CSCs in EMS is recommended, especially in complicated clinical situations that require the rapid initial setting of materials [30][96]. BC Putty shows similar apical sealing performance to MTA in vitro and may better induce tissue healing adjacent to the resected root surface [31][32][33][34][97,98,99,100]. A retrospective clinical study [35][101] showed that the success rates of 6 months to 9 years for teeth with ProRoot MTA and BC Putty root-end filling were 92.1% and 92.4%, respectively. The one-year overall success rate of EMS using BC Putty was 92.0% in another retrospective clinical trial [36][102]. In prospective clinical studies, the one-year success rates of MTA and BC Putty were all greater than 93%, indicating a good prognosis [37][38][103,104].
Apical surgery was the earliest field of bioceramic application. MTA and BC Putty are well-proven root-end filling materials with predictable outcomes. However, there is insufficient evidence to conclude that any material is superior to the other [39][40][105,106]. Nonetheless, more randomized controlled trials are needed to provide high-level evidence for their effectiveness.
Intentional Replantation
Intentional replantation (IR) is a method of extracting an intact affected tooth and replanting it in situ after treatment, which is suitable for the failure of EMS or root injury that cannot be repaired in the mouth [41][107]. Recent studies show that IR has a more consistent success rate of 88% to 95%, and it is considered a more commonly accepted therapeutic strategy [42][43][108,109]. IR is a cost-effective alternative to root canal retreatment and tooth extraction in appropriate cases [44][45][46][47][48][49][110,111,112,113,114,115]. The long-term success and survival of IR depend on numerous factors, one of which is the type of root-end filling material [50][116].
The application of MTA in EMS has achieved good clinical outcomes. However, some reports have argued that MTA may not achieve the same effect in IR. It was found that an extraoral time of more than 15 min and the use of ProRoot MTA as a root-end filling material in IR were significantly associated with a lower survival rate [51][117]. A prospective study showed that the replantation time over 15 min had a 28.6% risk of ankylosis and a 12.7% probability of persistent or emerged periapical radiolucency when retro-filled with ProRoot MTA, which significantly reduced the healing rate [52][118]. The long operation time of MTA and its susceptibility to blood contamination may lead to a decrease in its sealing ability and resistance to wash-out. Therefore, it is recommended to use fast-setting bioceramics for the root-end filling of IR. Many new bioceramics with good operability have been reported for IR. Good clinical results using BC Putty and CEM in IR can be seen in some case reports [53][54][55][56][119,120,121,122]. In case series, root-end filling with CEM for IR was also successful in 90% of teeth at a mean follow-up of 15.5 months [57][123].
There is no clear clinical treatment protocol or guideline for IR, which leads to differences in surgical procedures and the lack of specialized studies on filling materials. MTA is the most widely used material; however, its effectiveness is debatable. Case reports using BC Putty or CEM exist, but the research is of low quality. Therefore, further studies and long-term follow-up of clinical trials are required.
32. Root Canal Therapy
Root canal therapy is the most effective and most common method for treating pulpal and periapical diseases [58][124]. The single-cone technique is an easy-to-operate and time-saving method of root canal therapy, with sealer as the main material and gutta-percha as an auxiliary [59][125]. In addition, the GentleWave system utilizes advanced fluid dynamics to clean root canals, minimizing excessive cutting caused by mechanical preparation and reducing the risk of intracanal separation of Ni–Ti rotary instruments [60][61][62][126,127,128]. After root canal cleaning, hydraulic condensation with bioceramic sealer is used for root canal obturation, especially for irregular root canals. These techniques are increasingly dependent on the root canal sealer, so the fluidity and other physicochemical properties of the sealer play a crucial role in the success of treatment [63][129]. Bioceramic sealers, such as BC Sealer, possess good biocompatibility, superior fluidity, and chemical stability. When applied to the single-cone technique, bioceramic sealers have achieved satisfactory short-term clinical results [64][65][130,131].
The combinatory use of bioceramic sealers and the single-cone technique has achieved excellent outcomes. Root canal filling using gutta-percha/bioceramic sealer has a similar or shorter postoperative pain duration than gutta-percha/traditional sealer [66][67][132,133]. An overall success rate of 90.9% using the BC Sealer and single-cone technique was achieved from a retrospective study [68][134]. BC Sealer combined with the single-cone technique achieved an 88.7% success rate for initial treatment and a 63.9% success rate for retreatment in another retrospective study [69][135]. In prospective studies, the BioRoot RCS combined with the single-cone method has achieved a 1-year success rate of 90~97.44%, which is comparable to the 89~93.33% success rate of warm vertical condensation of gutta-percha using resin-based sealers [70][71][136,137]. A randomized clinical trial using epoxy and calcium silicate-based sealers in a single-cone technique showed no significant differences in postoperative pain or healing process [72][138].
Based on current evidence, the single-cone method combined with bioceramics has achieved satisfactory clinical results and has great operability. However, it is not currently accepted by most clinicians because of the lack of standardized clinical guidelines and the high reliance on root canal sealers. The use of the single-cone method remains controversial and requires long-term clinical trials with large sample sizes.
43. Vital Pulp Therapy
The treatment strategy for exposed vital pulp teeth has shifted to conservative and minimally invasive treatment, which is closely related to the development of bioactive dental materials in recent years [73][74][139,140]. VPT includes pulp capping and pulpotomy, which are methods for maintaining the vitality and function of the pulp after injury, decay, or restorative procedures [75][76][141,142]. The selection of the capping material is one of the keys to success, and MTA is a commonly used and widely studied material [77][24]. The American Association of Endodontics (AAE) recommends the use of CSCs in VPT, whose clinical application has been consistently successful [78][143].
43.1. Pulp Capping
Pulp capping refers to covering the dentin surface close to the pulp or covering an exposed pulp wound with a repair material to protect the pulp and eliminate the lesions [79][144]. Pulp capping can be divided into direct pulp capping (DPC) and indirect pulp capping (IPC), depending on whether the material is in direct contact with pulp tissue [74][80][140,145]. The application of MTA in DPC has been the most studied topic. MTA used in DPC can achieve predictable clinical outcomes and is more effective in maintaining the long-term viability of the pulp than calcium hydroxide [81][82][83][84][85][146,147,148,149,150].
Other bioceramics have been reported for pulp capping. BioAggregate has excellent cellular compatibility in vitro and is a possible alternative to MTA for pulp capping [86][55]. BC Putty also has comparable biocompatibility with MTA for pulp tissue and can induce the formation of restorative dentin bridge [87][88][89][151,152,153]. Biodentine and MTA Angelus lead to satisfactory results in vitro, showing a light inflammatory response and pronounced barrier formation for mineralization [90][154]. The dentin bridge formation thickness of Biodentine is higher than that of CEM and MTA in a clinical study, but it shows greater pulp inflammation [91][155]. Biodentine has better clinical and histological performance as a DPC agent compared with Dycal (a calcium hydroxide-based product), as demonstrated by reduced postoperative pain and sensitivity, thicker dentin bridge formation, and less pulpal inflammation [92][93][156,157]. Biodentine, with its high operability and competitive price, has no distinguishing success rate for DPC in 1–3 years compared to MTA [94][95][96][97][98][99][158,159,160,161,162,163].
Based on available evidence, bioceramics promote reliable mineralized tissue formation and sustained pulp vitality. MTA and Biodentine are currently the most studied materials and are recommended for pulp capping. Although other bioceramics (such as BC Putty and CEM) have been studied less, they have also achieved better results than traditional calcium hydroxide.
43.2. Pulpotomy
Pulpotomy is a method to remove inflamed pulp tissue and cover the pulp section with a pulp-capping agent to retain healthy pulp tissue [100][164]. Pulpotomy can be divided into partial and complete pulpotomy according to the depth of pulp resection [101][165]. The application of MTA in pulpotomy can achieve outstanding results, which is supported by high-quality evidence [102][103][104][105][106][107][166,167,168,169,170,171]. Studies have shown that MTA has a better success rate than calcium hydroxide in mature permanent teeth undergoing partial pulpotomy [108][109][110][172,173,174].
The use of Biodentine in pulpotomy results in a success rate similar to that of MTA and reduces the likelihood of discoloration [111][112][175,176]. A prospective randomized controlled trial gave evidence that MTA and Biodentine used in pulpotomy have 100% and 89.4% success probabilities after 2 years, respectively [113][177]. Prospective studies showed a one-year success rate of 95–98.4% for total pulpotomy with Biodentine in mature permanent teeth with irreversible pulpitis [114][115][178,179]. Additionally, pulpotomy using hydraulic calcium silicate cements (HCSCs) has an 81–90% radiological success rate [116][180]. BC Putty shows a good response to partial pulpotomy in clinical cases, and it may be an effective covering material for the pulpotomy of young permanent teeth after trauma [117][118][119][181,182,183]. Total pulpotomy with BC Putty successfully treated 90.5% of permanent teeth with irreversible pulpitis in a prospective cohort study [120][184]. In clinical trials using CEM and MTA for the pulpotomy of vital immature permanent molars, all cases (49 teeth) showed pulp survival and signs of continuous root development after 1 year [121][185]. Randomized controlled trials have found that MTA and CEM are equally effective pulpotomy agents in mature permanent teeth of different age groups, with a 5-year success rate of over 98% [122][186]. Pulpotomy used with MTA/CEM is recommended as a viable and favorable alternative to root canal therapy in mature permanent teeth, demonstrating considerable and effective postoperative pain relief [123][124][125][126][127][128][129][187,188,189,190,191,192,193].
Although root canal therapy is still the current standard treatment for mature permanent teeth with irreversible pulpitis, the advent of bioceramics makes pulpotomy an effective alternative [100][164]. The determination of strict indications is necessary, and randomized clinical trials with sufficient sample sizes and long-term follow-up are still needed for further comparison of the two treatments [130][131][194,195]. Based on the current evidence, MTA is still the first choice for pulpotomy, although bioceramics such as Biodentine, BC Putty, and CEM also have great potential.
54. Apexification and Regenerative Endodontic Treatment
Since dental stem cells can promote root development, some strategies are used to treat young permanent teeth with pulp necrosis but incomplete root development [132][133][134][196,197,198]. Apexification and regenerative endodontic therapy are effective options for periapical tissue healing and open apical closure [135][136][137][138][199,200,201,202]. In addition to dental stem cells, biomaterials are also key factors in therapy [139][203].
54.1. Apexification
Apexification refers to the placement of drugs in the root canal, which causes the root to continue to develop, and the apical foramen to narrow or close [140][204]. Compared with calcium hydroxide, MTA used in apexification induces better apical closure and less inflammatory infiltration and reduces the frequency of treatment and the possibility of tooth fracture [141][142][143][205,206,207].
Many new bioceramics have been reported for apexification [144][208]. Biodentine and ProRoot MTA prevent early root fractures during the first 30 days of apexification, and this effect is superior to that of NeoMTA Plus [145][209]. Several cases used Biodentine in apexification and suggested that it might increase the resistance of immature teeth [146][147][148][149][150][151][210,211,212,213,214,215]. A randomized clinical trial showed that using Biodentine in the apexification of nonvital immature molars achieved good apical healing comparable to MTA and reduced treatment time [152][216]. There is no difference in the amount of leakage measured by the glucose leakage model when MTA and BC Putty are used for apexification in vitro [153][217]. However, there are also studies in which the leakage of MTA is less than that of BC Putty measured using the radioactive isotope method in the apexification model [154][218]. BC Putty also promotes the continued maturation and development of immature teeth with nonvital pulp [155][219]. The clinical success rates of BC Putty, MTA, and calcium hydroxide are similar; however, the former two materials require a shorter time for the formation of an apical barrier and only need a single visit [156][220].
MTA is currently recommended as the first-choice treatment for apexification. Biodentine, BC Putty, and other materials used for apexification almost be seen in case reports. Therefore, more high-quality assessments are needed in the future.
54.2. Regenerative Endodontic Treatment
Regenerative endodontic treatment (RET) is an alternative to apexification in suitably selected cases and shows better results than apexification in increasing root thickness and length [135][157][199,221]. Blood clot induction, also known as revascularization, is a commonly used RET technique. Revascularization stimulates blood clots in the periapical tissues of teeth after removing the infection in the root canal by disinfection, which recruits stem cells around the root to proliferate, differentiate, and promote the formation of “new pulp tissues” in the root canal [158][159][222,223]. MTA is the most widely applied sealing material in RET and has an excellent overall survival rate [160][161][224,225].
The sealing material for revascularization is in direct contact with the blood clot, and this is why it is required to be bioactive, biocompatible, noncytotoxic, and antimicrobial [162][226]. New bioceramics are strong candidates for the coronal sealing of previously established blood clot stents. Biodentine, ProRoot MTA, and RetroMTA induce the proliferation of SCAPs, which can be used as effective sealing materials for RET [163][227]. Biodentine promotes the release of transforming growth factor-beta 1 (TGF-β1) from the root canal dentin and leads to higher mineralization of human apical papilla cells (APC) than ProRoot MTA [164][228]. MTA and Biodentine used for RET show similar void characteristics and tortuosity and there are no differences in sealing ability in vitro [165][229]. Biodentine has been used as a barrier material for RET, with good results in some case reports [166][167][168][230,231,232]. RET using bioceramic putty can result in partial or complete apical closure at an average of 54.4 months [169][233]. BC Putty and MTA used in RET result in apical healing and root maturation in 75% of teeth, which is thought of as a viable treatment option [170][234].
The level of evidence for the use of bioceramics other than MTA in RET is low, as it is generally seen in in vitro studies and case reports [171][235]. RET is a future direction for pulp necrosis in immature teeth, and more high-quality studies are needed to support it with the development of bioceramics.
65. Perforation Repair
Tooth perforation is the connection between the wall of the root canal and periodontal space [172][236]. The repair of perforation by bioactive nonabsorbable materials is the key to treatment. The three most widely recommended materials for sealing root perforations are calcium hydroxide, MTA, and CSCs [173][237]. MTA is the standard material for the repair of furcal perforations and can produce a favorable histological response [174][238]. NeoMTA Plus shows better early biocompatibility than MTA Angelus, EndoSeal MTA, and ProRoot MTA, providing similar sealing ability [175][176][239,240].
Other bioceramics have also been used for perforation repairs. Biodentine and MTA result in similar periradicular inflammatory responses and bone resorption when they are used to seal perforations [177][178][241,242]. When used for sealing the furcal perforation, Biodentine is more effective in preventing dye leakage than MTA [179][180][181][182][243,244,245,246]. Biodentine and MTA can reduce the risk of potentially harmful stress in the perforation region [183][247]. BC Putty used in repairing furcation perforations shows similar and even less leakage to MTA in vitro [184][185][248,249]. CEM and Portland cement are used to repair furcal perforation, and their ability to prevent dye and bacterial leakage is similar to MTA [186][187][188][250,251,252]. Premixed bioceramics are promising materials for repairing furcal perforations in primary molars, with better sealing performance and clinical outcomes than MTA [189][253].
Although data on the long-term efficacy of MTA in the treatment of perforation are scarce, available evidence suggests that MTA has a great sealing ability [190][191][254,255]. Biodentine, BC Putty, and others have shown similar and even better sealing performances in perforation repair than MTA in vitro. However, there are only a few clinical studies on these materials, and more high-quality studies are required to evaluate their clinical applications.
76. Root Defect Repair
Root defects such as the palate–radicular groove and root resorption are intractable diseases with a poor prognosis, and various surgical and nonsurgical methods are used to repair them [192][256]. Bioceramics are often preferred because the materials may directly contact the tooth and periodontal and apical tissues [193][257].
76.1. Palatal-Radicular Groove
The palatal-radicular groove (PRG) is defined as a developed groove in the root, usually located on the palatal side of the maxillary incisors [194][258]. PRG is a developmental abnormality, most likely due to genetic factors [195][259]. PRG must be filled to block the infection pathway after cleaning and preparation, and the filling materials include glass ionomer cement (GIC), composite resin, and CSCs [196][260].
The mechanical properties and biocompatibility of the filling material are important considerations because PRG is distributed in both the tooth crown and root. Bioceramics have an advantage over the other materials mentioned above in this respect. MTA for PRG repair has been observed in some cases, and its poor operability and risk of teeth discoloration are major concerns [197][198][199][261,262,263]. Moreover, Biodentine has been used to seal PRG to achieve long-term preservation of affected teeth with combined periodontal lesions in some cases [200][201][202][203][264,265,266,267]. IR for PRG of maxillary incisors has also been reported, in which BC Putty was used to fill the PRG [204][205][268,269].
PRG-related studies are limited to case reports. There are no in vitro studies and prospective clinical studies, and even fewer studies on filling materials for PRG. With the development of bioactive materials, it is hoped that more materials can be applied to the study of PRG to provide a basis for treatment.
76.2. Root Resorption
Root resorption, which can be simply divided into internal and external resorption, refers to the loss of dental tissue on the inner or outer surfaces [206][207][270,271]. The management of root resorption can include conservative or surgical treatment, depending on the location, degree, and extent of occurrence [208][272]. Root resorption and perforation appear together in many cases, and MTA used in their treatment has been reported to have satisfactory long-term results [209][210][211][212][213][214][215][216][273,274,275,276,277,278,279,280].
Bioceramics other than MTA have been reported in some cases. BC Putty, MTA, and Biodentine provide higher fracture resistance to the teeth when filling the internal resorption compared with the gutta-percha/sealer technique [217][218][281,282]. Moreover, Biodentine and CEM used in the treatment of tooth absorption have shown good results in case reports [219][220][221][222][223][224][225][283,284,285,286,287,288,289]. Nonsurgical repair using bioceramic putty is an effective treatment option for external cervical resorption [226][290]. Bioceramic sealers (MTA Fillapex and BC Sealer) show high PH values, calcium release, and good root strengthening potential, and have the potential to repair root absorption defects with satisfactory results [206][227][270,291].
