Minimally Invasive Access Cavity Designs: A Review

ABSTRACT

Access cavity preparation, chemo-mechanical preparation, and obturation make up the majority of the endodontic triad. Every action should be carefully observed by the clinician. In the last two decades, endodontics has seen advancements in both technology and materials. Given the technical advancements in applied sciences, magnification, and imaging techniques, minimally invasive therapies are currently used in the medical and dentistry industries. This review article will describe minimally invasive Access cavity designs and their advantages and disadvantages in Endodontic treatment.

INTRODUCTION AND BACKGROUND

Minimally invasive access cavity design focuses on conserving tooth structure during root canal procedures, enhancing tooth longevity and function.[1,2,3,4] Traditional techniques often remove significant tooth material, risking structural integrity.[5,6,7,8] Recent advancements prioritize preserving dentin and enamel, reducing the likelihood of fractures and improving outcomes. This review explores the evolution, techniques, and benefits of minimal invasive access cavity designs, emphasizing their impact on dental practice and patient care, highlighting critical studies and innovations contributing to this paradigm shift.[9,10,11,12,13,14]

REVIEW

Description of minimally invasive access cavity designs

The convenience of the clinician in access preparation is the foundation of traditional endodontic access design. The healthy tooth structure that is present coronally, cervically, and radicularly is preserved to the greatest extent possible during minimally invasive access cavity preparation to increase the short- and long-term success of the tooth. These designs call for the eradication and prevention of the disease to be carried out without the needless loss of tissue, which will raise the success rate of non-surgical endodontic treatment.[15]

The conservative access preparation preserves the existing tooth structure by removing the least amount of tooth structure possible to lengthen the life of the tooth. As far as we are aware, several pieces of literature have described how to prepare an access cavity traditionally. Therefore, we will further discuss about the minimally invasive method of access cavity preparation.[16]

Contracted conservative access cavity

The enamel is through from the central fossa to create an access chamber. It only continues until little files are able to detect the orifices. It is a condensed version of traditional access cavity preparation, as the name implies. The pericervical dentin, which is essential for pressure transfer from the occlusal table into the root and increases the fracture resistance of the endodontically treated tooth, is preserved by creating this type of minimally intrusive access cavity.[17]

Since more dentin was preserved by reducing cavity size, the advantage of contracted access cavity preparation indicated increased tooth fracture resistance. The chances of ineffective canal instrumentation and the occurrence of procedural errors could be increased by cavity preparation, which is a drawback.[18] Additionally, the danger of bacteria-associated contamination and the potential for missing some root canal openings increases with the size of the access cavity.[19,20]

Ultraconservative Access Cavity

• NINJA ACCESS CAVITY PREPARATION

The point access is also referred to as the “ninja access.” Enamel is stretched apically with a slight increase in dimension during this access cavity preparation, through the central fossa or the deepest region of the occlusal surface[1,21,22] All of the canals should be reached through this little access cavity, and root canal preparation and obturation should be performed.[21]

• TRUSS ACCESS CAVITY

Another design – “orifice-directed access.” The dentinal bridge between the mesial and distal canals (in mandibular molars) or the buccal and palatal canals (in maxillary molars) is preserved with this preparation, which is done just to identify the canal orifices and prepares the root canals.[23,24] This design is further improved such that each canal can be accessed by a different orifice. The truss access, however, is not standardized.[25,26,27,28]

By placing the bur parallel to the long axis of the tooth in an oval shape buccolingually using an Endo access bur, access to the pulp chamber is acquired from the occlusal surface to the roof of the pulp chamber. The bur is then positioned over the distal pulpal horn to get access to the pulp chamber. A diverging wall is created in the access cavity by rotating an Endo Z bur quickly inside the pulp chamber.[29] The main focus of benefits is on maintaining healthy tooth structure while using a minimally invasive procedure.[30] The retention of the mesial and distal ridges considerably improves the fracture resistance of teeth.[27] Pericervical dentin preservation. During conservative access preparation, the soffit is prepared.[31]

This design cannot be attempted for all teeth during endodontic treatment and there is a chance of pulp tissue remnants, which are disadvantages. It has also been discovered that endodontic treatment outcomes are poor if shaping and cleaning protocol is not followed due to the lack of convenience in this design.[31]

Computer-assisted access cavity preparations

To establish a predictable path to the root canal space while preserving the tooth structure, this entails the use of software and 3-dimensional imaging.[1] This computer-assisted approach was initially developed for implant implantation and is regarded as a type of minimally invasive access. There are two different categories for this cavity preparation method.

• GUIDED ACCESS CAVITY PREPARATION

Dr Charles M. initially introduced it for the implantation of implants. CBCT is used to design an access cavity. To locate the physicians’ and patients’ jaws in three dimensions, overhead cameras are used. The clinician positions and aligns the bur after taking a look at the software interface.

This produces a personalized stent that directs the access drill to the desired place using intraoral scanners and CBCT imaging.[23]

The Guided Access Cavity has some drawbacks, including prolonged treatment planning, postponed treatment, the need for a straight approach to the canal’s location at the apex, difficulty accessing posterior teeth, and drilling that becomes too heated.[1,32] The drawback of this cavity design is that there may be artifacts that appear during CBCT scans and impact the precision with which the canals are located.

CBCT scanning is performed after intraoral scanning. Then, a virtual drill path that is created by merging CBCT and intraoral scanning data is planned on the computer screen, along with a virtual sleeve for guiding the bur. Based on this, templates are created, and their fit is evaluated.

Marks are then placed through the template sleeves to designate the area of the access cavity. To obtain access to the root canal, this area is first prepped.[33]

• DYNAMIC NAVIGATION ACCESS PREPARATION

Passive optical technology, CBCT imaging, and software support the dynamic navigation interface, which directs the bur’s penetration of tooth structure in real-time to obtain the right access cavity. As can be seen in the Guided Access cavity, this method does not necessitate a lot of planning.[1] The Dynamic Navigation Access preparatory procedure requires numerous intraoral attachments before the start of the treatment plan. This equipment is pricey. A few in vitro studies and case reports that served as proof of concept for computer-assisted access cavities have recently been published in the field of endodontics.[23,32]

They seem to hold potential, particularly for the control of calcified structures.

CONCLUSIONS

Recent technological and arsenal advancements, including the use of 3D imaging, an operational microscope, high lighting, thin ultrasonic tips, irrigant activation, and flexible instruments, contribute to the success of minimally invasive endodontic treatment.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.