Dental BBS

 找回密码
 register
搜索
热搜: 活动 交友 discuz
查看: 65|回复: 8

Detailed considerations for the treatment of dental prosthesis after minimall...

[复制链接]

10

主题

66

帖子

358

积分

管理员

Rank: 9Rank: 9Rank: 9

积分
358
发表于 2018-9-16 15:19:41 | 显示全部楼层 |阅读模式
In recent years, with the development of dental pulp biology, dental pulp therapy instruments and materials, and adhesive technology, minimally invasive endodontics (MIE) guided by the concept of reducing dental tissue damage has been implemented. Clinical practice and research have shown that good crown sealing is an important guarantee for the success of natural tooth preservation. However, there is no unified standard system for the treatment of crown restoration interface after MIE.

Coronal restorations are also important for the prognosis of teeth after pulp preservation and pulp regeneration. However, the treatment of pulp capping materials such as mineral trioxide aggregates (MTA) or the bonding interface between bioceramics and resins is still a weak point in the study of bonding restoration, and there is no bonding procedure between them. Consensus. Therefore, this article will focus on a series of problems in the interface treatment of MIE teeth, such as repair timing, material selection, processing procedures and so on, in order to provide help for clinical decision-making.

回复

使用道具 举报

10

主题

66

帖子

358

积分

管理员

Rank: 9Rank: 9Rank: 9

积分
358
 楼主| 发表于 2018-9-16 15:20:18 | 显示全部楼层
Consideration of restoration interface after 1. root canal therapy

Crown repair time after 1.1 root canal therapy

Good crown repair can effectively prevent reinfection, and the effect on periapical health is even more important than the quality of root canal filling. With the popularization of MIE concept, root canal therapy is imperfect without any subjective symptoms for a long time and all clinical examinations are normal. The authors suggest that resin filling or temporary crown restoration should be performed after assessing occlusal status, and root canal therapy should be performed three months to six months instead of immediately. This is the embodiment of "patient-centered" treatment plan, which not only reduces a large number of difficult re-treatment, but also saves the cost and time for patients.

For this kind of imperfect root canal treatment, the precondition of no root canal re-treatment is only to restore the crown without post. In order to restore the post-core crown, one third of the apical closure must be carefully analyzed. If the filling is not perfect (lack of length, width or clinical symptoms), root canal retreatment should be performed. There is no consensus on the timing of pile preparation. Lyons et al. found that immediate post preparation had better root canal closure because of the removal of gutta-percha by the heat carrier before the root canal sealant was hardened. The effect of pile preparation time on the bonding of fiber posts has not yet come to a unified conclusion, which needs further study. Our team's recent results in vitro and clinical studies have shown that immediate post-driving with irootSP paste does not seem to affect apical sealing and fiber post bonding strength (data not yet published). The progress of root canal filling, piling time and their interaction can be reviewed.

10

主题

66

帖子

358

积分

管理员

Rank: 9Rank: 9Rank: 9

积分
358
 楼主| 发表于 2018-9-16 15:20:40 | 显示全部楼层
1.2 consider the age of repair.

There are few studies on the age of restoration, and it is generally believed that full crowns can be restored only after 18 years of age. The reasons are as follows: (1) Teenagers often have lower clinical crowns and insufficient occlusal space; (2) Gingival instability in adolescents, such as anterior teeth; (3) Potential orthodontic needs of patients; (4) Menstruation. Economic reasons, if the "permanent" repair, with the growth of age, the impact of aesthetic problems, resulting in unnecessary disputes. Tickotsky et al. found through retrospective analysis that in order to avoid occlusal disorder, alveolar ridge resorption, adjacent teeth inclination and space loss after removal of permanent teeth in adolescent patients with severe tooth defects, timely crown restoration after root canal therapy is a better program. The most important consideration is to protect the crown of the young teeth from splitting and have to extract the teeth. The author thinks that after full communication, the young teeth should be repaired timely and necessary after root canal therapy.

1.3 repair interface processing

1.3.1 affects root canal therapy drugs and irrigating fluids.

A retrospective study of 775 teeth after root canal therapy by Willershausen et al. showed that restoration within 2 weeks after root canal therapy had a higher survival rate and immediate bonding was recommended. However, chemicals used during root canal therapy can alter the dentin structure and affect the bonding effect. Zinc oxide root filling paste or temporarily sealed cement will remain oil layer, which will affect resin polymerization and bonding. It has been gradually eliminated by clinical practice. As a widely used root canal irrigation fluid, NaClO not only affects the mechanical properties of dentin, but also destroys collagen and forms oxygen-rich layer on the surface of dentin. EDTA can eliminate the influence of NaOCl on bonding, and improve the quality of mixing layer and improve the durability of bonding. In addition, the results showed that Na2S2O3 could reduce the oxygen-enriched layer left by NaClO and significantly enhance the dentin-resin bonding strength of NaClO/EDTA treatment. 2% chlorhexidine can inhibit the degradation of collagen fibers by a broad spectrum of metalloproteinases, maintain the stability of the mixed layer for up to 14 months, and significantly improve the stability of resin-dentin bonding.

Treatment of 1.3.2 root canal orifice

Under MIE concept, pericervical dentin can be preserved to the maximum extent. Immediate closure of the crown after root canal filling with 1-2 mm composite resin deep below the root canal orifice can reduce the microleakage of the crown and the extensive use of traditional crown restorations for post, and avoid excessive removal or accidental root dentin during post preparation. Injury. In order to obtain an ideal bonding interface, it is very important to treat the dentin surface effectively before bonding. Because the self-etching system can interact with eugenol infiltrating into the mixed layer, the root canal orifice barrier can be pretreated and bonded by the fourth generation adhesive system and filled with flowing resin. If phenol-free sealants were used in previous operations, the sixth generation adhesive system or resin-modified glass ionomers could be used.

10

主题

66

帖子

358

积分

管理员

Rank: 9Rank: 9Rank: 9

积分
358
 楼主| 发表于 2018-9-16 15:21:05 | 显示全部楼层
Case selection and material selection for 1.3.3 post and core repair

There are many kinds of restoration methods after root canal therapy. At present, there is no definite evidence-based medical evidence and there is a great subjectivity in choosing the restoration scheme. With the improvement of bonding and mechanical properties of resin or porcelain restorative materials, MIE can protect more residual tooth tissues and improve the structural strength and flexural resistance of restored teeth by using high inlay and retention crowns. However, it must be pointed out that the residual tooth tissue significantly affects the effect of tooth restoration after root canal therapy, and 1.5-2.0 mm dentin collar is an effective mechanical retention guarantee. Therefore, there should be at least 5mm hard tissue from the crown to the alveolar ridge, of which 3mm guarantees the health of soft tissue and 2mm crown guarantees the "dentin shoulder collar effect".

Whether post-core can enhance the resistance of teeth after root canal therapy is still controversial. When the crown tissue defect of teeth after root canal therapy exceeds 50%, post-core can be considered, and post-core plus full crown is generally used. However, post preparation increases the risk to the restoration process. If possible, post preparation should not be expanded after root canal therapy. The stress concentration experiments including photoelastic experiments and finite element analysis were reviewed systematically. It was found that the stress of metal posts was mainly concentrated at the end of Posts and that of fiber posts was mainly concentrated at the neck of teeth.

The elastic modulus of fiber post is similar to that of dentin, and it can distribute occlusal force better. More and more evidence shows that fiber post can improve the fracture resistance of pulpless teeth. The length, diameter, shape and surface treatment of fiber post, the type of adhesive and the position of root canal all affect the bonding strength of fiber post. There are three points of view in the selection of bonding system: (1) Complete etching, pretreatment and bonding (LuxaCore, ParaCore, Multicore flow, RebildaDC); (2) Self-etching and combination of pretreatment (such as Panavia F2.0, Parapost ceme) NT); (3) self adhesive cement (e.g. Rely-XUnicem, Clearfil SA cement). Liu et al. found that the bond strength between Rely X Unicem and Panavia F2.0 was significantly stronger than that of the other two groups by comparing the influence of DMG Luxa Core Smart Mix Dual, Multilink Automix, Rely X Unicem and Panavia F2.0, and the bond strength of DMG group was significantly enhanced by sandblasting pretreatment.

Composite resins are often used as post-core materials because of their good physical and mechanical properties and bonding ability. However, there are some problems such as polymerization shrinkage, high coefficient of thermal expansion and so on, which may lead to micro-leakage or even failure of restoration. In recent years, with the in-depth study of bulk resins, it has been found that the mechanical strength, edge tightness and other aspects have been improved, significantly reducing the polymerization shrinkage and polymerization stress. Jung et al. compared the properties of two bulk filling flow resins (SDR, Venus Bulk Fill) and bulk filling resins (Tetric N-Ceram Bulk fill, Sonic Fill). It was found that the bulk filling resins had less shrinkage stress at the edge of polymerization and better edge adaptability, while the bulk filling flow resins had lower flexural strength despite of the surface. A conventional composite or nano composite resin can not effectively buffer the bite force.

10

主题

66

帖子

358

积分

管理员

Rank: 9Rank: 9Rank: 9

积分
358
 楼主| 发表于 2018-9-16 15:21:32 | 显示全部楼层
Alrahlah et al. found that the solidification depth of SonicFill, Tetric Evo Ceram Bulk Fill was better by Vickers hardness test. It is suggested that the gingival wall and medullary floor should be filled with bulk filling flow resin (SDR etc.). SonicFill and other bulk filling resin can be used to cover the gingival wall and medullary floor for internal reconstruction before crown restoration.

10

主题

66

帖子

358

积分

管理员

Rank: 9Rank: 9Rank: 9

积分
358
 楼主| 发表于 2018-9-16 15:21:51 | 显示全部楼层
2. preservation of vital pulp and interface treatment after dental pulp regeneration

2.1 timing of restoration

The most commonly used capping material MTA initial solidification time is about 2.75h, the final solidification time is about 3D. When will the subsequent repair be more appropriate? Recently, some scholars tested the shear bond strength (SBS) of each group after MTA was mixed with composite resin and glass ion at different time points, and found that the SBS of resin bonded with MTA at 2.75 h and 3 d after MTA was higher than that at instant, while the SBS at instant and 2.75 h was higher than that at 3 d after MTA was mixed with glass ion. In all two cases, the highest SBS of 2.75h was detected.

Tsujimoto et al. used two-step self-etching system to bond MTA and composite resin to detect the microhardness of the interface. It was found that the microhardness of the 10-minute group was higher than that of the 1-day and 7-day groups, and no interface separation or cracks were found in the 10-minute group. The authors speculate that the repair procedure does not affect the continuation of hydration within MTA, and therefore suggest that composite resin repair should be performed immediately after MTA pulp capping therapy is completed. Similarly, Neelakantan et al. tested the interface SBS after MTA bonding with composite resin. The results showed that the immediate SBS value was significantly higher than that of 45 min and 24 h groups regardless of the bonding system. Therefore, it was suggested that MTA should be repaired immediately after pulp capping with composite resin.

On the contrary, Atabek et al. mixed MTA at different time points (4, 24, 48, 72 and 96 h) and applied different adhesive systems to repair the composite resin. The SBS of the repair interface was detected and found that the SBS of each group of adhesive systems increased with time, and tended to be stable after 96 h. Kayahan et al. also found that the interfacial compressive strength and surface microhardness increased with time, but there was no significant difference between 96h and 24h. Therefore, it was suggested that MTA should be mixed at least 96h before bonding. The different results may be attributed to the different bonding systems, treatment conditions and subsequent repair materials used in various experiments. Therefore, the timing of direct resin repair after MTA pulp capping therapy has not been clearly and uniformly concluded, which needs further study.

10

主题

66

帖子

358

积分

管理员

Rank: 9Rank: 9Rank: 9

积分
358
 楼主| 发表于 2018-9-16 15:22:21 | 显示全部楼层
2.2 selection of bonding system

Does 2.2.1 require adhesives?

There are few studies on whether MTA or composite resin needs adhesives. Tsujimoto et al. used two-step self-etching system to treat the repairing interface between MTA and resin, and found that there was no significant difference in microhardness test between the adhesive group and the non-adhesive group. But in the observation of interface surface morphology, the interfacial separation or cracks were clearly observed in the groups of non-adhesive for 1 D and 7 d. Therefore, the study suggests that the use of adhesive is better in MTA composite restorations after pulp capping.

Selection of 2.2.2 bonding system

In the bonding repair of MTA and composite resin, the total etch system usually obtains better adhesive effect. Studies have shown that the total etch system SBS is significantly higher than the one step self etching system. After phosphoric acid etching, the surface characteristic crystal structure of MTA sample disappears, forming a unique etching mode with internal pores. This structural change may be the reason why the MTA sample has higher bonding strength than the self-etching system.

The factors affecting the bonding strength of the self-etching system include: (1) completing the combination of hydrophilic and hydrophobic monomers in one step, interfering with the polymerization reaction in the bonding process; (2) the strength of the adhesive polymer itself is low; (3) the inhibition of dissolution/oxidation of the material leads to the monomer of the resin in the light reaction process. Lower degree of polymerization. In addition, some scholars interpret the low bonding strength of the self-etching system as the incompatibility between the bonding system and the repair materials. However, some studies have found that the bond strength of one-step self-etching system is higher than that of full-etching system.

Neelakantan et al. Interpreted it as a one-step self etching system. The pH value is higher and the solvent has better wettability. At the same time, the 5% fillers contained in the one-step self etching system reduced the shrinkage stress during the reaction. Potassium fluoride is contained in the components of the adhesive system. The release of fluoride can strengthen the sealing of dentinal tubules and reduce the postoperative sensitivity. Fluorine can enhance the surface strength of Portland cement, thereby reducing cohesive fracture and improving the bonding properties. In addition, the self-etching adhesive system can also reduce the operation time and steps, make its application more convenient and less technical sensitivity, which is conducive to clinical operation. Alzraikat et al. found that one-step self-etching system exhibited higher SBS in the bonding repair of new light-cured calcium silicate and traditional glass ions with composite resin. In addition, some studies have shown that there is no significant difference in the bonding strength between total etching and self-etching bonding systems in the bonding process between pulp capping materials and composite resins. Therefore, after pulp capping therapy, there is no definite conclusion about the pros and cons of total etching or self-etching bonding system in the final repair.
回复 支持 反对

使用道具 举报

10

主题

66

帖子

358

积分

管理员

Rank: 9Rank: 9Rank: 9

积分
358
 楼主| 发表于 2018-9-16 15:22:39 | 显示全部楼层
Is 2.3MTA and other pulp materials directly bonded to composite resin?

After the preservation of vital pulp, subsequent repair materials need to ensure no leakage. It has been found that the acid etching treatment before resin bonding and the natural characteristics of solvents in the bonding system will affect the mechanical properties and bonding strength between the pulp capping agent and the composite resin. Hashem et al. Believe that crown restoration after pulp capping should have a lower compression force. Some scholars suggested adding a layer of transitional repair material between the pulp capping material and the final repair material.

Savadi Oskoee et al. found that the SBS between resin modified glass ionomer (RMGI) and composite resin was much higher than that between MTA and CEM calciumen riched mixture and composite resin. RMGI is composed of fluid resin, which is easy to form chemical bonding reaction with resin repair material. The bonding strength between RMGI and composite resin is higher than that of polymer. Considering the longer solidification time of MTA and CEM cement, Savadi Oskoee suggested that a layer of RMGI could be covered as a transitional material before the final resin repair.

With the emergence of a new type of self-adhering flowable composite (SAFC), it has been proved that the SBS between MTA, CEM cement and SAFC is higher than that between RMGI and SAFC. Considering that SAFC can omit the process of acid etching, washing and bonding, SAFC is suggested to be better than RMGI as a transition repair material. At the same time, the study also showed that the SBS with one-step self-etching bonding was higher than that without the use of adhesive when SAFC was used. Can composite resins directly cover MTA or bioceramic materials? Is the opportunity for direct coverage immediate or the two visit? Scholars have not reached a consensus on whether to use adhesive or not and what kind of adhesive system to cover resin materials directly. It is recommended that MTA or bioceramics should be covered with RMGI or SAFC immediately after application and then be repaired by resin.
回复 支持 反对

使用道具 举报

10

主题

66

帖子

358

积分

管理员

Rank: 9Rank: 9Rank: 9

积分
358
 楼主| 发表于 2018-9-16 15:22:55 | 显示全部楼层
3. conclusion

In modern stomatology, MIE guided by bond prosthesis has achieved the goal of restoring the normal function of the affected teeth and preserving them for a long time. The emergence of a higher pursuit of bonding repair interface processing is the exploration of MIE and the practice of excellence. At present, there is no definite evidence-based medical evidence for many problems in crown repair, and further research and clinical practice are needed to deal with the interface between new calcium-silicon materials and final restoration materials. More high-quality studies are needed on the treatment details of the dental restoration interface after MIE to provide guidance for finding the best clinical decision-making.
回复 支持 反对

使用道具 举报

您需要登录后才可以回帖 登录 | register

本版积分规则

QQ|Archiver|手机版|小黑屋|Dental BBS  

GMT+8, 2019-8-20 11:16 , Processed in 0.720169 second(s), 21 queries .

Powered by Discuz! X3.2

© 2001-2013 Comsenz Inc.

快速回复 返回顶部 返回列表