WO2020167153A1

WO2020167153A1 - Biomechanical device for controlling force in dental restorations

Info

Publication number: WO2020167153A1
Application number: PCT/PT2019/050002
Authority: WO
Inventors: Luis Manuel FERREIRA ROSEIRO; Rui ISIDRO FALACHO DA FONSECA ALMEIDA; Marco António LOURENÇO ESTEVES; Marco José DA SILVA
Original assignee: Instituto Politécnico De Coimbra; Rf & Lf - Dentistry Design Studio, Lda.
Priority date: 2019-02-13
Filing date: 2019-02-13
Publication date: 2020-08-20

Abstract

The present invention relates to a biomechanical device for controlling force in dental restorations, since excessive force can cause damage to the dental or restorative structure, while insufficient force when correctly seating the part can result in early and rapid degradation of the interface, infiltration, bacterial colonization and failure of the treatment. The present invention is based on a mechanical arrangement with three main structural elements: a structural element at the force application end, referred to as the tip (1), a structural element for handling the device, referred to as the grip (2), one of the ends of which has means for measuring force using information on the structural deformation thereof, and a structural element, referred to as the handle (3A) (3B), which performs a supporting and stabilizing function for the device according to the present invention and/or is used for coupling to an electronic data-acquisition and -processing system.

Description

DESCRIPTION

"" BIOMECHANICAL DEVICE FOR STRENGTH CONTROL IN

DENTAL RESTORATIONS "

FIELD OF THE INVENTION

The present invention relates to a biomechanical device for force control in dental restorations, therefore, integrated in the field of electromechanical engineering, with specific application in dental medicine.

BACKGROUND OF THE INVENTION

The recovery of a damaged tooth using indirect restorations is one of the most common activities in dentistry. In the restoration process, and according to the techniques used, there is a need to apply force in the insertion of the component that will rehabilitate the tooth and, in particular when indirect restorations applied with cementing agents are used. This force becomes essential to cause the flow of the cementitious material, thus improving the adaptation of the restorative piece to the tooth, reducing the space between them and consequently significantly increasing the prognosis and longevity of the restoration-tooth set.

Excessive force can cause damage to the dental or restorative structure and insufficient force for the correct seating of the part, can lead to early and rapid degradation of the interface, infiltration, bacterial colonization and treatment failure.

It is added that the force applied is dependent on the sensitivity of the dentist, and there are currently no devices that guarantee help in monitoring it, making it a subjective act in which in most cases a deficient force is used.

The device, object of the present invention, allows the monitoring and recording of the forces that are applied in the insertion of indirect restorations in prepared teeth. Thus, in addition to being extremely important for use in a clinical environment, it will also be a relevant tool in the context of dental students' learning, particularly in the field of manual perception and development of dexterity and fine muscle memory, with consequent contribution to the calibration of the force that is exerted in this type of dental restoration procedures.

STATUS OF THE TECHNIQUE OF THE INVENTION

As mentioned above, in dentistry, restoration procedures resulting from fractures or carious injuries, or aesthetic dental rehabilitation procedures are very common. Restorations can be straightforward, when a preparation is immediately filled in situ after its execution; or indirect when processed differently or in the laboratory (crown, onlay, overlay, veneer, among others) and later cemented, that is, glued to a dental preparation previously performed in the area of the tooth to be restored.

An indirect restoration has as main advantages the control over the contraction of the polymerization of the cement, a greater rigidity of the material and a better anatomy with regard to the point of contact, which can be performed in composite resin or ceramic. It has greater hardness and resistance to fractures. Any indirect restoration requires a cementing agent that joins it to the prepared tooth (Cardoso, A. S. (2016). Adhesive cementation: Evaluation of the film thickness in different materials and techniques - Pilot Study. Coimbra). Cementation is a decisive step to guarantee the retention, marginal sealing and durability of the restorations. In this procedure, a force is applied by the doctor that ensures adequate adhesion between the parts to be cemented, that is, the tooth-restoration set. This force, applied through a structural support element, must be of such an order that it causes the flow of the cementing material and the proper settlement of the piece, thus improving the prognosis and longevity of the restoration-tooth set, but without being excessive given which can cause damage to the dental or restorative structure (Sousa, FI (2017). Different techniques for adhesive cementation: comparison between two composite resins. Coimbra).

Although it is clear in the literature that force control is important in the context of insertion of the restoration into the tooth, there are still no devices to guarantee the control of the force that is applied, which is dependent on the sensitivity and experience of the patient. dentist, who even with experience may never have had the opportunity to train this procedure in a calibrated manner. The current subjectivity of this procedure often causes the application of a deficit force for fear of applying excessive force, which leads to the removal of the restorative part, with a thickness of cement greater than the desirable and proven in the scientific literature, leading to a degradation early and rapid interface, infiltration of the same, bacterial colonization and failure of the treatment in such a way that it may even imply the loss of the dental piece in the short / medium term. The present invention allows the force applied in the tooth restoration procedure to be properly monitored.

A search was made for devices existing in the state of the art, as well as those that have been the subject of publication, but that are not available in a commercial context. It was found that the existing devices aim to apply force, however they do not allow it to quantify or monitor. A device stands out in the research carried out: OptraSculpt Pad (marketed by the company Ivoclar Vivadent), which is a device produced in synthetic polymeric material and metallic material, which has the purpose of functioning as a restorative material carrier in composite resin for restorations direct, having been adapted by dentists empirically to clinical use to exert force in indirect dental restorations. It has a ring for retaining cushions, which are small pieces of polymeric material that allow the application of resin in direct restorations more easily and which, in clinical adaptation, also serves to perform the contact with the restoration in the insertion of indirect restorations. This device can be autoclaved and its pads are disposable.

In addition to the application of the present invention to the application and measurement of force in dental restorations, namely in indirect restorations (crowns, onlays, overlays, veneers, among others), and can be used on all the patient's teeth, the device may also have other purposes, namely when there is a need for procedures to monitor the applied force, such as in the area of periodontology through the modification of the active tip for the conformation of the probe, allowing the measurement of the gingival sulcus with the appropriate force, thus avoiding injury to the fibers insertion and damage of this vital structure.

Another possible application, by changing the conformation of the active tip, lies in the measurement of force applied in orthodontics with elastics. In this specialty of dentistry, it is essential to apply constant forces of known magnitude in the treatment and movement of teeth. If the forces are too intense, severe resorption and destruction of the tooth roots may occur, leading to the loss of these teeth; if forces of sufficient magnitude are not exerted, the treatment is ineffective. There are elastic bands with different strengths that the orthodontist dentist must vary to increase or decrease the strength, however not only does the elastic interfere in this parameter since the distance between the anchor points promotes great variations that the orthodontist cannot control, and the same can elastic be appropriate or not depending on the distance between the teeth, the size of the teeth, the size of the arch and other individual characteristics of each patient.

Thus, the invention described here may also work for the measurement of strength in each specific case, giving a clear indication to the orthodontist dentist of the real force applied and guiding the decision on choosing the most suitable elastic.

DESCRIPTION OF THE FIGURES

INDICATION OF REFERENCE NUMBERS

(1) Tip of the device:

A. For application of pillows;

B. Periodontal probe;

C. Hook;

(2) Handle of the device;

(3) Device cable;

A. For cable connection to the interface;

B. For coupling the electronic system;

(4) Pad application hole on the tip (IA) of the device;

(5) Zone of application of force in the restoration;

(6) Hole in the handle (2);

(7) Area of contact with the handle (2);

(8) Fitting pin at the end (1), by inserting it into the hole (6);

(9) Washer;

(10) Deformation zone for placing strain gauges (20); (11) Hole for passing wires;

(12) Handle handling zone (2);

(13) Cable fitting hole);

(14) Push pin on the handle (2);

(15) Hole for the passage of the wires to the opposite end;

(16) Cylindrical central cable support zone (3A) (3B);

(17) Cylindrical central support zone with conical cable end (3B) (3A) and electronics coupling;

(18) Perforated cover;

(19) Cover;

(20) Extensometers.

Figure 1 - Schematic and simplified representation, according to the invention; isometric view. Illustrates the relationship between the tip (1), specifically this is the tip (IA) for applying pads, the handle (2) and the handle (3A), as well as the geometry of the complete device.

Figure 2 - Representation in a schematic and simplified perspective, according to the invention; exploded view of the device (top). Illustrates the various tips (IA, 1B, 1C), which fit into the handle (2), which in turn can be inserted into and the cable (3A) which is sealed by the perforated cover (18), which allows connection by conductors to an interface.

Figure 3 - Representation identical to figure 2, but cable o (3B), which presents at the opposite end to handle (2) a cover (19). In this representation the electronic system is integrated.

Figures 4 and 5 - Schematic and simplified representation of the tip (IA) for applying pads; top view (figure 4) and bottom view (figure 5). Illustrates the cushion coupling hole (4), the geometry of the tip and the force application zone (5).

Figure 6 - Representation in a schematic and simplified perspective, here the example of the tip (IA), side view, but they could be another tip (1B) or (1C), since what we want to highlight are the elements: fitting hole (6) on the handle (2), as well as the stop area (7) on the handle, which are identical for any type of tips.

Figures 7, 8, 9 and 10 Schematic and simplified representation, according to the invention, of the handle (2); two isometric views (figures 7 and 8) and two lateral views (figure 9) and top (figure 10). Illustrates the tight fitting pin (8) on the tip, the washer (9) on the tip, the deformation zone (10) for placing strain gauges (20), the holes (11) (13) for the passage of electrical conductors and the handling area (12) of the handle, as well as the geometry of that area and the cable fitting hole.

Figure 11 Schematic and simplified representation, according to the invention, of the cable (3A); isometric view. Illustrates the central support zone (16) which at one end has a locking pin (14) on the handle and the hole (15) for the passage of electrical conductors and at the other end the perforated cover (18), as well as the geometry of the cable support.

Figure 12 - Schematic and simplified representation, according to the invention, of the cable (3B); isometric view. Illustrates the central support zone (17), which at one end has a locking pin (14) in the handle and hole (15) for the passage of electrical conductors, and at the other end the cover (19), as well as the geometry of the zone cable support, which will have an electronic system integrated inside.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is based on a mechanical configuration with three main structural elements:

• a structural element at the end of the application of force, here designated generically as a tip (1), which can have different configurations depending on the application, in particular it can be:

the tip for applying pads (IA); the periodontal probe tip (1B);

the hook tip (1C);

• a structural element for handling the device, called a handle (2), which at one end has means of measurement of the force through the information of its structural deformation; and

• a structural element, called a cable

(3A) (3B), which has the function of supporting and stability of the device object of the present invention and / or for the coupling of an electronic data acquisition and processing system; this cable (3A) (3B), is hollow, has a central cylindrical support zone (16) with an internal hole (15) for the passage of electrical signal cables, or a cylindrical central support zone with conical end (17) in order to couple an electronic data acquisition and processing system inside; at one end it has a cover

(19) or a perforated lid (18) and at the other end means for engaging the handle (2).

Either end (IA) (1B) (1C) has the characteristic that gives it its function at one end, that is:

• the pad application point (IA) has a pad coupling system for applying force, and has a pad coupling hole (4) and a force application area (5) at one end;

• the periodontal probe tip (1B) has a periodontal probe that allows the control of the force exerted in the periodontal probe between gingiva, tooth and bone; and • the hook tip (1C) has a hook that allows the coupling of elastics used in orthodontics.

On the opposite side, that is, at the opposite end, all the tips (IA) (1B) (1C), have a fitting hole (6) in the handle (2) and a stop area (7) in the handle (2) .

Any end (1) (IA) (1B) (1C) and the handle (2) are joined by means of fitting (8), being able to be specifically a tight fitting.

The tip end (IA) may have a slightly different geometry from the figures to accommodate various types of cushions.

The tips (IA) (1B) (1C) can also incorporate a silicone membrane or similar material, removable or not, disposable or washable, for total or partial protection of the tip or the rest of the device. If they are removable, they will be disposable and replaced after each use. If fixed, they will have to be disinfected in the usual procedures used in dentistry.

They can be made of metal alloy or polymeric material, which must be biocompatible with the oral cavity. They can be used for single use, disposable type, or for reuse, with the possibility of disinfection in an autoclave. The handle (2) has an area with well-defined and optimized geometry with an ergonomic shape for the correct stable and precise handling of the device, presenting a deformation zone (10), where strain gauges (20) will be applied, this deformation zone ( 10) is located between a washer (9) of the tip (1) and a handling area (12) of the handle (2). This handling area (12) and the washer (9) have exactly the same geometry as the handle (2). In addition, the handle (2) has at one end, the end of the handling zone (12), a hole (13) for fitting the handle (3A) (3B), and at the other end, the one that follows the washer (9) , locking means (8) to the tip (1), which can be a tight locking pin.

In addition, it is necessary that the free edge of the handling zone (12), in contact with the deformation zone (10), have two holes (11) for the passage of electrical conductors.

The handle (2) and any of the cables (3A) (3B) are preferably joined by means of locking means (14) to the hole (13), which can be locking pins, threaded connection or pressure fitting.

The washer (9) is intended to be a stop of the tip (1) to make the coupling more rigid. The deformation zone (10) where the strain gauges (20) are located, preferably has a rectangular section geometry, obtained through calculation by the finite element method. This is the ideal geometry to guarantee a strain range measurable by strain gauges (20), while ensuring that the device does not break mechanically.

This section, as well as its length, can vary in order to adapt the strain range to the consequent forces exerted in the various types of application of the device. This area can be protected with silicone or similar material, in order to allow disinfection of the device after each use, without damaging the strain gauges (20). The handling area (12) of the handle (2) may have a different geometry from that shown in the images, in order to improve the device's ergonomics. It can also allow the placement of a silicone membrane or similar material, removable or not, disposable or washable, for total or partial protection of the handle.

If it is removable, it will be disposable and replaced after each use. If it is fixed, it will have to be disinfected. The system for fixing the handle (2) to the tips (IA) (1B) (1C) may include some type of mechanical brake for greater safety in use and have a different geometry from that shown in the images, to ensure greater safety. It must be constructed of biocompatible material.

The cable fitting (3) on the handle (2) can be by screw connection or by pressure fitting. In order to guarantee the seal, it will have a retaining ring in malleable and biocompatible polymeric material.

The cable (3A) (3B) features: • at one end, means for engaging (14) the handle (2), which have means (15) for passing electrical conductors through the cable (3A) (3B);

• a support zone in the user's hand, which is called the central support zone (16) (17);

• at the other end has a cover

(19) totally isolated; or a perforated cover (18), this second cover (18) allows the passage of the electrical conductors to an external interface for data acquisition and processing, has the purpose of securing and ensuring the tightness between the electrical conductors and the device.

The cover (19) will be made of polymeric material to allow wireless connectivity in case the cables (3B) (3A) are made of metallic material. Its fitting in the cable (3B) (3A) can be by screw connection or by pressure fitting that will have a retaining ring in malleable and biocompatible polymeric material, to guarantee the sealing. Any of the cables (3B) (3A) may allow the placement of a silicone membrane or similar material, removable or not, disposable or washable, for total or partial protection of the handle. They can be built in biocompatible material, either in metallic alloy or in polymeric type material.

The cable (3A) (3B) has fitting means (14) on the handle (2) and a hole (15) for conducting conductors electrical. In the case of connection of the device by electrical conductors to an external interface, the cable (3A) (3B) may have a support area (16) in the user's hand and a perforated cover (18). If the device has an integrated electronic system, the cable (3A) (3B) may have a support zone (17) in the user's hand (17) that will have the said electronic system inside, and a cover (19).

The central support zones (16) (17) may have different geometries than those shown in the figures and described here, so that they can offer better ergonomics in contact with the hand and can also vary their dimensions in length, or even for couple the different components of the electronic system.

The device, object of the present invention, can be built entirely in a single material or in a combination of several materials. It may be composed of metallic alloy, plastic or acrylic materials or any material of the polymeric type, produced by additive or subtractive manufacturing technologies, as well as by casting or injection of material. In any of the situations, the materials must have characteristics that allow their disinfection.

It allows the insertion of electromechanical control units for safety in the use of the device, as well as for monitoring the force exerted, both in a learning context and in a clinical context. Eventually an app compatible with Android and / or iOS systems can be developed to monitor and control the applied force, which can be with biofeedback that is based on a serious game for the student to be able to train and learn to exercise the force.

The present invention thus has the purpose of monitoring the force, as well as its registration over time. It will emit sounds or light signals, representative of the applied force, or have a wireless interface for connection to a computer or smartphone. The electronic component of the device incorporates a temperature measurement system, timers, and biofeedback mechanisms. The software application will also be very advantageous when used in a teaching aspect, based on these mechanisms, a fundamental role in the learning and analysis of the force exerted by the students, with the implementation of a Serious Game.

Claims

1 REPLICATIONS

1. Biomechanical device for force control in dental restorations, characterized in that it comprises at least one tip (1) (IA) (1B) (1C) that has means of fitting (6) (7) to a handle (2) and said handle (2) having at one end means for engaging (8) with the end (1) (IA) (1B) (1C) and at the other end for engaging means (13) with at least one cable (3A) (3B); and by:

a) the handle (2) has a deformation zone (10), where strain gauges (20) will be applied, this deformation zone (10) is located between a washer (9) and a handle handling area (12) (2), and that handling zone (12) and the washer (9) have geometry identical to that of the handle (2) and at one end means to engage (13) the cable (3A) (3B);

b) the cable (3A) (3B) has at least one central support zone (16) (17), at one end it has at least one cover (18) (19) and at the other end it means for fitting (14) (15 ) to the handle (2).

Device according to the preceding claim, characterized in that the tips (IA) (1B) (1C) have at the end without connection to the handle (2) a cushion coupling hole (4) and a force application zone (5 ); or a periodontal probe; or a hook.

Device according to the preceding claims, characterized in that the tips (IA) (1B) (1C) and / or the cables 2

(3B) (3A) incorporate a silicone membrane or similar material, removable or not, disposable or washable.

Device according to the preceding claims, characterized in that the tips (IA) (1B) (1C) can be constructed of metal alloy or of polymeric type material.

Device according to the preceding claims, characterized in that the locking means between the tip (1) (IA) (1B) (1C) and the handle (2) are a locking hole (6), an abutment area ( 7) and a tight fit (8) and may include a mechanical brake.

Device according to the preceding claims, characterized in that the means for fitting between the handle (2) and the cable (3A) (3B) are an internal hole (15) for the passage of electrical conductors through the interior of the cable (3A) (3B ), locking pin (14), hole (13), threaded connections or pressure fittings.

Device according to the preceding claims, characterized in that the deformation zone (10) has geometry of rectangular section.

Device according to the preceding claims, characterized in that the free edge of the handling zone (12), in contact with the deformation zone (10), has two holes (11) for the passage of electrical conductors. 3

Device according to the preceding claims, characterized in that the deformation zone (10) and the handling zone (12) of the handle (2) can have a silicone membrane or similar material, removable or not, disposable or washable.

Device according to the preceding claims, characterized in that the cable (3A) is hollow and the central support zone (16) is cylindrical.

Device according to the preceding claims, characterized in that the central support zone (17) is cylindrical with a conical end (17) that can be connected inside it to an electronic data acquisition and processing system.

Device according to the preceding claims, characterized in that the cover (18) is punctured allowing the passage of electrical conductors to an external interface.

Device according to the preceding claims, characterized in that the cover (19) is made of polymeric material and its fitting on the cable (3B) (3A) is by screw connection or by pressure fitting which may have a retaining ring.

Device according to the preceding claims, characterized in that it is made entirely of a single material or a combination of several materials. 4

15. Device according to the preceding claims, characterized by being composed of metal alloy, plastic or acrylic materials or any material of the polymeric type, produced by additive or subtractive manufacturing technologies, as well as by casting or injection of material.