Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0001—Impression means for implants, e.g. impression coping
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0048—Connecting the upper structure to the implant, e.g. bridging bars
  • A61C8/005—Connecting devices for joining an upper structure with an implant member, e.g. spacers
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0048—Connecting the upper structure to the implant, e.g. bridging bars
  • A61C8/005—Connecting devices for joining an upper structure with an implant member, e.g. spacers
  • A61C8/0069—Connecting devices for joining an upper structure with an implant member, e.g. spacers tapered or conical connection
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0048—Connecting the upper structure to the implant, e.g. bridging bars
  • A61C8/005—Connecting devices for joining an upper structure with an implant member, e.g. spacers
  • A61C8/0068—Connecting devices for joining an upper structure with an implant member, e.g. spacers with an additional screw

Definitions

• the present invention relates generally to dental implants and, more particularly, methods and devices for impression to restore dental implants. It comes to solve: mould inaccuracies, cost, labour time and infection control problems.
• impression techniques are used in implant dentistry while some require gingival displacement while making impressions. Others, such as the pickup impression technique, do not require any gingival retraction. However, this pickup impression technique requires use of additional parts such as: implant analog, impression copings, and impression transfers which have an impact on accuracy and cost of the restoration.
• clinicians must maintain a minimum bulk of 0.2-millimeter thickness in the sulcus area, which they can achieve by retracting the gingiva for at least four minutes before making the impression. Rapid closure of the sulcus requires that clinicians make theimpression immediately after removing the retraction material.
• Direct optical impressions are limited to line of sight, which is facilitated by performing gingival retraction to expose finish lines.
• the powders used when making optical impressions to reduce reflectivity and make tooth surfaces measurable can influence impression accuracy by increasing tooth surface thickness.
• Clinicians regard the indirect capture of digitized information as being potentially more accurate; however, the way in which clinicians can acquire data is influenced by the thickness of the impression material in the sulcus area. Significant errors can result from thin impression margins with a radius less than the contacting probe tip.
• Indirect scanable body impressions U.S. Pat. No. 6,558,162 patented May 6, 2003 and U.S. Pat. No. 6,790,040, patented Sep. 14, 2004 by Implant Innovations Inc ) have so far very good clinical results. However, that particular method does not require gingival displacement. Unlike direct impression techniques, the indirect scanable body does not retrieve any information about the abutment what may be in some cases indispensable mostly for the aesthetics.
• the implant surrounding fibre structure does not provide the same level of support and is not able to prevent the collapse of retracted tissues to the same extent, which complicates attempts to successfully make impressions. This is particularly true in situations in which the depth of sulcus is greater than average, such as when an implant has been placed deeply.
• Retraction is the downward and outward movement of the free gingival margin that is caused by the retraction material and the technique used.
• Relapse is the tendency of the gum to go back to its original position. It is influenced by the elasticity or memory of the tissue and by the rebound forces of adjacent attached gingiva that was compressed during retraction. A 0.2-mm sulcular width is necessary for there to be sufficient thickness of material at the margins of impressions so they can withstand tearing or distortion on removal of the impression.
• Displacement is a downward movement of the gum that is caused by heavy-consistency impression material bearing down on unsupported retracted gingival tissues.
• Collapse is the tendency of the gum to flatten under forces associated with the use of closely adapted customized impression trays.
• the gingival tissue may or may not rebound to its original position.
• the gingival tissue responds viscoelastically, and recovery time is much longer than the duration of the deforming force application. If too much trauma occurs and if the gingival tissue is too thin, irreversible alteration will take place.
• Cord Clinicians place retraction cords by using cord-packing instruments; however, many commonly used hand instruments (such as the Hollenbach carver tip) were not designed for this application.
• the forces generated by pointed or wedge-shaped instrument tips may be traumatic to the relatively fragile junctional epithelium around implants, whereas tooth's gingival tissues may be more forgiving of this type of force.
• Some manufacturers make purpose-designed packing devices that have smooth, non serrated circular heads that can be used to place and compress twisted cord with a sliding motion.
• Other manufacturers make devices with serrated circular heads for use with braided cords. The thin edges of these serrated circular heads sink into the braided cord, and the fine serrations keep it from slipping off and cutting the gingival attachment.
• Retraction cords were developed for use with natural teeth. They provide more effective control of gingival haemorrhage and exudates when used in conjunction with drugs than when used with no drugs. The use of a single retraction cord often provides inadequate gingival retraction.
• the dual-cord technique in which the first cord remains in the sulcus reduces the tendency for the gum to recoil and partially displace the setting impression material. Results from one survey showed that 98 percent of prosthodontists use cords, with 48 percent using a dual-cord technique and 44 percent using a single-cord technique.
• Placement of retraction cords can cause injury to the sulcular epithelium and underlying connective tissues, as shown by the results of experiments involving dogs' teeth.
• the filaments or fibres of conventional cords also may cause residual contamination of sulcular wounds, creating foreign body reactions and exacerbating inflammation.
• Healing of the sulcus can take seven to 10 days.
• Use of minimal force is necessary when packing cords to protect Sharpey fibres, and application of excessive force is inappropriate because it may cause bleeding, gingival inflammation and shrinkage of marginal tissues.
• Epinephrine commonly is used to medicate retraction cords since it provides effective vasoconstriction and haemostasis during retraction. It is, however, associated with significant local and systemic side effects, which investigators have reported occurring during 33 percent of applications.
• Synthetic Sympatho-Mimetic agents that mimic the actions of epinephrine are more effective and safer than epinephrine.
• Aluminum Sulphate and aluminum potassium sulphate act by precipitating tissue proteins with tissue contraction, inhibiting transcapillary movement of plasma proteins and arresting capillary bleeding. Both are haemostatic and retractile, which causes minimal postoperative inflammation at therapeutic concentrations, although concentrated aluminum potassium sulphate solutions can cause severe inflammation and tissue necrosis.
• Aluminum Chloride the action of aluminum chloride is similar to that of aluminum sulphate, which is an astringent that causes precipitation of tissue proteins but less vasoconstriction than epinephrine.
• Aluminum chloride is the least irritating of the medicaments used for impregnating retraction cords, but it disturbs the setting of polyvinylsiloxane impression materials.
• Aluminum potassium sulphate and aluminum chloride medicated cords are more effective in keeping the sulcus open after clinicians remove the cord than are epinephrine-medicated cords.
• Ferric Sulphate owing to its iron content, ferric sulphate stains gingival tissues a yellow-brown to black color for several days after a clinician has used it as a retraction agent. The accuracy of surface detail reproduction during impressions can be modified by ferric sulphate, as it disturbs the setting reaction of polyvinylsiloxanes. Thus, it is important for clinicians to remove all traces of medicament from the tissues carefully before recording the impressions.
• Chemicals in an injectable matrix Injecting 15 percent aluminum chloride in a kaolin matrix opens the sulcus, providing significant mechanical retraction. When compared with having a cord packed into the sulcus, an injection of 15 percent aluminum chloride in a kaolin matrix resulted in less pain for patients and was easier and quicker to administer. Furthermore, its effectiveness in reducing the flow of sulcular exudates is similar to that of epinephrine-soaked cords.
• An inert matrix a polyvinylsiloxane material for gingival retraction was introduced in 2005. It works by generating hydrogen, causing expansion of the material against the sulcus walls during setting. The manufacturer has reported advantages including gentle placement without need for local anaesthesia, visibility in the sulcus due to its bright color, ease of removal and absence of the need for haemostatic medicaments. Potential drawbacks are that it may not improve the speed or quality of retraction obtained and that it likely is less effective with subgingival margins. Clinicians place deep implants with subgingival margins relatively frequently since implant placement is dictated largely by the location of available bone.
• Nd:YAG lasers are contraindicated near implant surfaces, because they tend to absorb energy, which causes them to heat up and transmit the heat to bone, owing to the effects of this laser's wavelength on metal. There is also a tendency for Nd: YAG lasers to damage the fragile sub junctional epithelium at the sulcus base around implants.
• Erbium: Yttrium-Aluminum-Garnet (Er: YAG) lasers with a wavelength of 2,940 nm are reflected by metal implant surfaces and minimally penetrate the soft tissues, so they are relatively safe to use.
• the haemostasis achieved with the Er: YAG laser is not as effective as that achieved with the carbon dioxide (CO2) laser.
• the prime chromophore of the CO2 laser which has a wavelength of 10,600 nm, is water, and it reflects off metal surfaces. When used near metal implant surfaces, CO2 lasers absorb little energy, with only small temperature increases ( ⁇ 3oC) and minimal collateral damage. CO2 lasers do not alter the structure of the implant surface.
• the attached gingiva serves as a barrier that prevents exposure of the implant body over time through recession.
• CO2 lasers may be significantly useful in some implant impression situations, they are invasive, thus failing to meet the ideal objective of a truly conservative technique.
• Electrosurgery Clinicians can use Electrosurgery effectively to widen the gingival sulcus around natural teeth before placing the cord and to provide haemostasis by coagulation. However, Electrosurgery is not recommended around implants because there is significant risk that the contacting electrode may arc by conducting electric current though the metal implant structure to the bone rather than via the more dispersive gingival tissue pathway. The concentrated electrical current at the tip of electrodes can generate heat, which may cause osseous or mucosal necrosis.
• Rotary curettage involves the use of a high-speed turbine to excise the gingival tissue quickly and create a trough around the margins.
• rotary curettage has little effect on gingival margin heights if adequate keratinized gingiva is present, although slight deepening of the sulcus may result.
• rotary curettage is inappropriate for use around implant restorations because of poor tactile control when cutting soft tissue, which could lead to bur contact damage to the implant surface and over instrumentation.
• the absence of keratinized gingiva at the base of the gingival sulcus surrounding the implant could lead to an exaggerated response to rotary curettage, including deepening of the sulcus and gross recession.'
• the most important objective in the impression process is to register and reproduce accurately the dental prosthetic field of the patient's mouth.
• the implant has no resilience or mobility and its ability to adapt to stress is very low. That means that the impression for implants should be even more accurate than impression for the natural tooth.
• the 3-D scanner with which a surface structure on a prosthetic field can be recorded in terms of height or depth differences has a projection optical path and an observation optical path, which make an angle with an optical axis of the 3-D dental scanner.
• a light source for emitting a group of light beams in the direction of the prosthetic field is arranged in the projection optical path.
• the light reflected by the prosthetic field is guided through the observation optical path to an image sensor of the 3-D dental scanner.
• the signals from the image sensor can be fed to an evaluation unit, so that an image of the surface structure can be created on a display device.
• This process eliminates the inaccuracy synonymous with conventional impressions . It also improves communication between the dental laboratory and the dentist, increases productivity, and lowers rejection rates.
• the present invention is a medical device that allows taking accurate impression of dental implant abutment in order to fabricate a high precision restoration.
• the main purpose of the invention is to displace the soft tissue that surrounds the implant abutment allowing the impression means (conventional or digital) to have an access to the surface of the abutment needed for optimal restoration.
• the main objective Impression Gingival Cuff is to exclude indirect procedures from the impression that alter and accuracy of the restoration.
• Impression Gingival Cuff When making impressions for fixed prostheses with aid of Impression Gingival Cuff, clinicians exposes an access and isolates the abutment's margins.
• the Impression Gingival Cuff installed on the abutment allows clinicians to record good impressions that meet these requirements.
• the precise reproduction of the abutment provides clinicians with crucial clinical information that allows them to fabricate exact-fitting restorations.
• the aim of the Impression Gingival Cuff is to atraumatically allow access for the impression material beyond the abutment's margins and to create space so that the impression material is sufficiently thick so as to be tear-resistant.
• the main purpose of the invention is to displace the soft tissue that surrounds the implant abutment allowing the impression means (conventional or digital) to have an access to the surface of the abutment needed for optimal restoration. It comes to solve: mould inaccuracies, infection control problems, and costs comprising material costs, chair time, labour time.
• Another object of the present invention is to simplify the process of taking impression of an implant abutment for cement retained restoration using the same method of impression as for natural teeth.
• Another object of the present invention is to implement the impression method which comprising following steps:
• the healing abutment is removed and the right abutment is chosen.
• the abutment is customized by trimming and grinding process.
• the abutment engages back to the proximal end of the implant.
• the low viscosity impression material is ejected in the space between and around the Impression Gingival Cuff ⁇ s wall and the abutment's proximal end, following insertion of the impression tray charged with high viscosity impression material.
• the outer surface of the Impression Gingival Cuff's wall pushes the surrounding soft tissue away from the abutment due to the rigidity and form of the Impression Gingival Cuff's proximal end.
• the inner surface of the Impression Gingival Cuff's wall creates a room allowing an access for the impression material to enter and register the details such as: shape, size and orientation of the abutment.
• the existence of the space between the abutment's proximal end and the wall of the Impression Gingival Cuff allows an access for the temporary acrylic material to enter the subgingival area of the abutment creating an emergence profile of the restoration.
• the Impression Gingival Cuff creates space between the abutment's proximal end and the wall of the Impression Gingival Cuff, building up an hydraulic pressure inside that space while the impression material in its liquid state. Due to that hydraulic pressure, there is an apical translation of the cuff allowing the impression material to advance beyond the most prominent part of the abutment.
• the abutment is installed in the patient's mouth shortly after removing from a sterile package. Unlike the previous art, the abutment is not sent to the lab, and thus can be spared from contamination in the non-sterile environment.
• FIG. 1 Illustrates an exploded view of major components of a screw indexed dental implant
• FIG. 1A Illustrates an exploded view of major components of a cone Morse non indexed dental implant
• FIG. 2 Illustrates a Gingival Cuff from occlusal view
• FIG. 2A Illustrates a Gingival Cuff from apical view drawing
• FIG. 3 Illustrates a fragment of an arc where the Gingival Cuff is mounted on the abutment
• FIG. 3A Illustrates a section 1,1 of FIG.3;
• FIG. 4 Illustrates a fragment of patient's mouth during impression take
• FIG. 4A Illustrates a section 2,2 of FIG.4;
• FIG.5 illustrates a fragment of final implant impression taken with an aid of a Gingival Cuff
• FIG. 5A illustrates a section 3,3 of FIG. 5
• FIG. 6 Flow work instruction diagram.
• FIG. 1 demonstrates the sequence of the assembly of a hexed-screw implant 103 and prosthetic accessories such as: an impression gingival cuff 100, an abutment 101, and a connecting screw 102.
• FIG. 1A demonstrates the sequence of the assembly of cone Morse implant 103 and prosthetic accessories such as: an impression gingival cuff 100, an abutment 101.
• the Impression Gingival Cuff as shown in FIG. 2 comprising an apical end 204 with apical opening 203 and an occlusal end 202 with occlusal opening 201.
• the main role of the apical end 204 comprises retention due to the prominent contour 104 of the abutment as it shown in FIG.1.
• the outer surface 205 characterized by its convex form divergent towards occlusal.
• the inner surface 206 characterized by its concave form convergent towards apical.
• the Impression Gingival Cuff as shown in FIG. 2A differs from the one in FIG.2 by the asymmetry of its wall 207.
• the asymmetrical wall 207 follows the thickness of the surrounding tissue, which often is not equal everywhere.
• FIG. 3 and FIG. 3A illustrate the section 1,1 of the fragment of a patient's mouth with an osteointegrated implant 103 in a jaw bone 302 and the Impression Gingival Cuff 100 which is pushed on its wall 207 by the soft tissue 301 in occlusal direction 303 against the resistance of the abutment's most prominent contour 104 orienting the Impression Gingival Cuff vertically.
• FIG. 4 and FIG 4A illustrate the section 2,2 of the fragment of a patient's mouth to show the process of impression when the impression material 407 in its fluid stage.
• the osteointegrated implant 103 situated between two natural teeth 404 and 405, equipped with the Impression Gingival Cuff 100 receives impression material 407 in the proximal end of the abutment 105.
• the impression tray 406 together with the impression material transmits hydraulic force to the adjacent teeth 404 and 405, soft tissue 301, abutment's proximal end 105, and to the Impression Gingival Cuff 100.
• FIG. 5 and FIG. 5A illustrate a section 3,3 of a negative mould 502 comprising an impression tray 506, Impression Gingival Cuff's registration 500, an abutment's body registration 501, a finish line registration 503, a small part of abutment's apical end registration 504, and a mucosal surface impression 505.
• FIG.6 is a flow of instructions which are implemented with the method of taking impression of implant restoration using Impression Gingival Cuff.
• the invention can comprise, consist essentially of, or consist of the stated materials.
• the method can comprise, consist essentially of, or consist of the stated steps with the stated materials.

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• Health & Medical Sciences (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Dentistry (AREA)
• Epidemiology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Dental Tools And Instruments Or Auxiliary Dental Instruments (AREA)

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• 2011
  • 2011-10-24 EP EP11835406.7A patent/EP2629696A1/de not_active Withdrawn
  • 2011-10-24 CA CA2852722A patent/CA2852722C/en not_active Expired - Fee Related
  • 2011-10-24 WO PCT/CA2011/050665 patent/WO2012055039A1/en active Application Filing

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