Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K6/00—Preparations for dentistry
  • A61K6/50—Preparations specially adapted for dental root treatment
  • A61K6/56—Apical treatment
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K6/00—Preparations for dentistry
  • A61K6/50—Preparations specially adapted for dental root treatment
  • A61K6/52—Cleaning; Disinfecting
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K6/00—Preparations for dentistry
  • A61K6/50—Preparations specially adapted for dental root treatment
  • A61K6/54—Filling; Sealing
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K6/00—Preparations for dentistry
  • A61K6/60—Preparations for dentistry comprising organic or organo-metallic additives
  • A61K6/69—Medicaments
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K6/00—Preparations for dentistry
  • A61K6/80—Preparations for artificial teeth, for filling teeth or for capping teeth
  • A61K6/831—Preparations for artificial teeth, for filling teeth or for capping teeth comprising non-metallic elements or compounds thereof, e.g. carbon
  • A61K6/838—Phosphorus compounds, e.g. apatite
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K6/00—Preparations for dentistry
  • A61K6/80—Preparations for artificial teeth, for filling teeth or for capping teeth
  • A61K6/84—Preparations for artificial teeth, for filling teeth or for capping teeth comprising metals or alloys
  • A61K6/847—Amalgams
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K6/00—Preparations for dentistry
  • A61K6/80—Preparations for artificial teeth, for filling teeth or for capping teeth
  • A61K6/849—Preparations for artificial teeth, for filling teeth or for capping teeth comprising inorganic cements
  • A61K6/876—Calcium oxide

Definitions

• ABSTRACT Dental methods and materials are disclosed for treating diseased or traumatized teeth and peridontal tissues.
• Physiologically compatible and soluble calcium phosphate compounds are prepared into a porous aggregate paste or powder and positioned adjacent to calcified tissue in contact with a blood supply.
• Such a technique permits improved methods for pulp capping procedures, root canal procedures, tooth replanting procedures and for corrective peridontal procedures,
• This invention relates generally to dental procedures for treating various trauma and disease conditions. More particularly this invention relates to materials and treatment procedures for enabling the growth of certain tissues to provide repairs of improved efficacy, predictability and longevity.
• Pulp capping treatment is used where there has been an exposure or opening into the pulp chamber of the tooth because the pulp has been insulted by disease or injury, An exposed pulp will become hyperemic, infected and devital if left untreated.
• the pulp capping procedure involves the placing of a material in the opening. This material should reduce the inflammation and allow the pulp to heal. Additionally, it should cause a dentinal bridge to be laid down spanning the opening into the pulp chamber via odontoblastic cells of the pulp.
• pulp capping materials Many different agents have been used as pulp capping materials with various degrees of success. Such agents include charcoal, ivory chips, sulfa drugs, a variety of antibiotics, anti-inflammatory corticoides, zincoxide-eugenol, calcium hydroxide and formocresol. At the present time, zinc oxide-eugenol and calcium hydroxide are the two materials most commonly employed in pulp capping treatment of adult teeth.
• the root canal may not be hermetically sealed by merely packing in a filling material.
• a non-sealed root canal will leak and allow the exchange of tissue fluids, metabolic breakdown products and probably initiate a chronic inflammatory condition.
• the purpose of this type of root canal procedure is to provide a wall at the apex against which a dense filling material may be packed thus preventing leakage or the ingrowth of undesirable cell structures into the root canal.
• the first is to gain access to the tooth apex surgically and mechanically close the apical opening through the insertion of a retrograde filling material, generally amalgam.
• the second is to introduce a filling material into the root canal by way of an occlusal access opening and obturate or fill the root canal.
• This filling material is generally gutta-percha.
• the third technique is to induce apical closure by placing a medicated dressing within the root canal. This dressing is conventionally a mixture containing calcium hydroxide.
• the third technique does produce some continued apical development and restriction. However, a substantial number of cases have been observed which do not respond to such treatment. Even after continuous treatment of 2 years and longer, there are cases which have not responded favorably.
• endodontic failure often occurs due to the recurrence of an acute inflammatory condition. This condition historically dictates surgical intervention for the placement ofa retrograde filling or the extraction of the tooth.
• peridontal ligament and periapical bone, supporting the involved tooth is often lost in the immediate area of the apex. conventionally, no separate definitive treatment is administered to allow for specific regeneration of these tissues. Healing or regeneration normally proceeds in these areas after the infective process has been eliminated. However, peridontal ligament fibers which are regenerated do not reorient themselves in the same fashion found prior to their destruction.
• the method of the present invention comprises the positioning of one or a plurality of physiologically soluble and compatible calcium phosphate compounds in various forms adjacent to various radicular and periapical calcified tissues and in contact with a blood supply, sufficient to permit formation of a blood clot in the calcium phosphate compounds.
• the invention contemplates the positioning of the calcium phosphate compounds at both the interior and the exterior of a tooth as described more particu larly in the following discussion.
• the method of the present invention enables the growth of the appropriate tissue elements; fibroblasts, odontoblasts, cementoblasts, and osteoblasts, at the appropriate sites, where needed, in or around a treated tooth.
• lt is another object ofthe invention to provide an improved pulp capping technique.
• Still another object of the invention is to provide an improved root canal technique.
• Yet another object of the invention is to provide an improved technique for replanting teeth.
• the invention contemplates the use of those compounds which have minimal or no harmful effects on the human body and additionally have a strong tendency to go into solution as calcium and phosphorous in body fluids to be either retained in or eliminated from one body.
• these materials may be used in the form of small crystals or ground into a suitable powder, it has been found particularly desirable to sinter particles of the desired material into porous blocks and then grind the blocks into a granular material. This sintering and subsequent grinding improves the porosity of the granular material.
• Sterile water, normal physiological saline solution, methyl cellulose or other suitable vehicle is then mixed in sufficient quantity with the finer forms of granular powder to form a putty-like mixture.
• This putty-like paste form of the preferred materials is advantageous for use in performing procedures of the present invention. it is very plastic and consequently, is easy to use. The smaller the particles are ground from the sintered block the more plastic and consequently the more advantageous the material becomes. It is also particularly desirable that the powder be ground into particles so small that the surface forces become an important factor in determining its properties, approaching colloidal properties.
• the tooth is prepared by removing decay and diseased tooth structures until sound hard dentin and viable pulp tissue is present.
• the diseased tissue is cleaned out with, for example, a dental bur or excavator and occasional irrigation using substantially conventional dental skills and techniques.
• the cavity formed in this manner must extend into communication with a blood supply. There must therefore be bleeding from a portion of the pulp.
• the size of the pulpal opening and the amount of diseased pulp tissue removed is, of course, dependent upon the extent to which the diseased pulpal condition has progressed.
• the size may vary from a minor insult upon the pulp to a pulpotomy which is the removal of all the coronal pulp down to the orifice of the root canals leaving only the pulp tissue in the root canal.
• a layer of the dry granular powder or putty-like material, described above, is then laid upon the bleeding pulp as a pulp capping agent.
• This layer may be lmm to 2mm thick.
• a dental base material is placed. Carboxylate cement or zinc ozide eugenol preparations have been used.
• the dental base, or cement layer keeps the pulp cap in place, provides some insulation and presents forces from being exerted directly upon the pulp cap and the pulp tissues while placing an amalgam or other restoration upon the tooth.
• the pulp capping agent operates in the following manner. Blood from the bleeding pulp seeps into the calcium phosphate compound and forms a blood clot having fibrin fibrils. Endothelial cells are then laid down to form a vascular blood supply within the porous aggregate of the capping agent. Undifferentiated mesenchymal cells then migrate out of the walls of the blood vessels into the matrix of the pulp capping agent. These cells differ entiate into fibroblasts or odontoblasts which begin laying down colagen, which in turn subsequently mineral izes. Calcifications are observed around and entrapping the particles of pulp capping agent.
• the pulp capping agent according to the pres ent invention, is slowly being resorbed.
• the calcifications become thicker and eventually replace the pulp capping agent and form a continuous and protective bridge.
• the cells adjacent to the pulpal aspect of the bridge appear to be true odontoblasts which lay down what appears to be secondary dentin.
• the odontoblasts of the pulp tends to remain in close association with the tissue of the dentinal bridge.
• the pulp often retreats from the bridge as from a foreign body and local foci of necrosis are often seen as well as internal resorption of the root canal walls.
• PULP CAPPING EXPERIMENTS Twenty-eitht teeth of four cynalmolgus monkeys were used in this experiment. Radiographs were taken before and after each pulp-capping procedure. Molars and pre-molars were selected as teeth of choice because of their larger pulp chambers. Upper right first molars and upper right pre-molars were used as control teeth utilizing calcium hydroxide. B-phase tricalcium phosphate was used in the remaining molar and premolar teeth as the pulp capping agent.
• the animals were anesthetized with Sernylan and Pentobarbitol. Atropine was used to decrease saliva flow. The teeth were isolated under rubber dam and disinfection was attempted using Betadine solution for five minutes. The occlusal portion of the vital tooth was opened with a high speed No. 4 round bur. This same bur was used to remove the roof of the pulp chamber. The vital pulp tissue of the chamber was removed with a small spoon excavator hoping to reduce injury to the remaining vital pulp tissue in the root canals. After the pulpotomy was completed, hemorrhage was controlled with a sterile cotton pellet. Pressure was applied until a blood clot formed on the canal tissue stumps. Excess blood and clot were rinsed from the chamber with physiological saline.
• Calcium hydroxide powder plus physiological saline was mixed into a paste and used as the control pulpcapping material.
• B-phase tricalcium phosphate powder and physiological saline was mixed into a similar type paste.
• Calcium hydroxide paste was used in seven teeth and B-phase tricalcium phosphate paste was used in twenty-one teeth.
• Pulpal hemorrhage was controlled by pressure application of sterile cotton pellets followed by the application of the pulp capping materials on the exposure site. Due to evaporation of the saline solution, it was difficult to place the same amount of paste over each exposure site.
• the monkeys were anesthetized with Sernylan and sacrificed by profusion with per cent formalin to allow 2, 3, 5, 8, l6 and 24 weeks studies to be considered. After death the mandible and maxilla were removed, stripped of soft tissue and sectioned so one tooth remained in each section. After fixing the block section in 10 per cent formalin for two weeks, the sections were demineralized in 5 per cent formic acid. The specimens were then imbedded in paraplast and cut serially at 6-10 microns. Each section was cut longitudinally in a mesio-distal plane. Every fifth section was stained routinely with hematoxylin and eosin stain and examined microscopically. In areas of importance to the study, every section was stained.
• the calcified matrix is more mature with evidence of less calcium phosphate particles in the individual compartments. Viable cells, perhaps fibroblasts or ostoid-producing cells are evident within areas of the matrix.
• the odontoblastic layer is very healthy from the matrix to the apex.
• the predentin layer is thickened only at the coronal portion where it unites with the calcified matrix.
• the pulpal tissue is very healthy, noninflammatory and is supplied by many blood vessels. Histological serial sections show the calcified matrix is complete in two specimens from side to side of the canal. The other specimen is almost complete from side to side of the canal. Periapical tissue is healthy and shows no inflammation.
• the pulp capping technique described above has been performed on approximately 30 human teeth. To date, the teeth are vital, asymptomatic, and are in function.
• the root canal procedure is used for the apexification of young devital teeth or the apexitication of devital, mature teeth that have undergone apical root resorption.
• An advantage of the procedure now described is that the root canal proce dure may be accomplished without surgery.
• An acess opening is made through the crown portion of the tooth on the lingual or occlusal aspect.
• the access opening must be large enough and contoured properly so that when the dentist instruments to the apex with files, no interference is met.
• the instruments must be positioned so that the entire interior portion of the root canal down to the open apex is biomechanically cleansed and shaped. This is done according to standard dental practice through a combination of filing and intermittent irrigation using a material which will dissolve necrotic debris and remove break down products. Once the walls are relatively smooth and the interior of the tooth free of necrotic dentin and pulp, resolution of the abcess will usually proceed.
• endodontic files are used in cleaning the interior of the tooth roots.
• the largest file for example, might have a diameter of 0.8 millimeters.
• a physiologically compatible and soluble calcium phosphate compound preferably prepared as described above is then packed into the apical 3 or 4 millimeters of the root canal.
• the calcium phosphate compound is pushed" so that it is slightly extruded out of the open apex, and allows blood to infiltrate the calcium phosphate.
• the compound may be positioned exteriorly of the root by injecting some of the material out of the bottom of the tooth root prior to packing the interior of the apex.
• a relatively soft temporary filling material such as gutta-percha is then used to fill the remainder of the canal.
• the human body Over the next five or six months the human body will begin first, to resolve the abcess formed at the exterior of the tooth root. Additionally, the fresh blood supply will initially allow a blood clot to form in the calcium phosphate compound. This will result in the formation of a vascular supply which will supply cells which mature and lay down a colagen-like matrix in the manner similar to that described above with the pulp capping technique. Eventually, an osteodentin barrier will be formed across the apex in a manner, it is believed, similar to that described above with the pulp capping procedure.
• cushioning ligament With other root canal procedures involving peridontal damage, some sort of cushioning ligament is formed during normal healing of the abcessed region between the tooth and the bone. However, the observed cushioning ligament after such normal healing is merely a dense, basket-like, fibrous network with no particular alignment of its fibers.
• the fibers of the peridontal ligament begin near the crown portion of the tooth in a nearly vertical orientation. As one descends along the root of the tooth the fibers are found to be more and more oblique until finally at the apex of the tooth the fibers are generally horizontally aligned. With this orientation the peridontal ligament is able to effectively withstand the type of forces encountered at the various positions on the tooth. For example, the peridontal ligament near the upper root portion of the tooth adjacent the crown, generally must withstand lateral and shear forces, while the ligament at the base of the tooth must withstand compressive forces.
• the ligament formed during normal healing without treatment according to the present invention the ligament often has no particular orientation at the root apex and therefore does not provide for proper distribution of forces.
• the remarkable result observed with the present invention is that the peridontal ligament is formed with naturally oriented fibers. Since peridontal ligament tissue is laid down by fibroblasts, it appears that the use of the described calcium phosphate compounds causes or enables the growth of fibroblasts which have more naturally functioning characteristics.
• cementum and bone are also formed. Therefore cementoblasts and osteoblasts are also caused or enabled to be formed naturally by the proper use of a calcium phosphate compound. In this manner the treated tooth is held in a firm, solid foundation, permitting normal function.
• ROOT CANAL EXPERIMENTS Four female cynalmolgus monkeys, ranging approximately from four to six years of age were used as the experimental animals.
• the dentin type material filled about 90% of the total circumference of the root canal leaving only a very small opening.
• Peridontal ligament had not only formed but it had reassumed its normal form and orientation and presumably its function. Bone morphology appeared normal with no active resorption of bone or tooth seen at any place in the teeth where tricalcium phosphate had been used. There was therefore a very high predictability of apical closure when tricalcium phosphate was used according to the present invention.
• a dry tricalcium phosphate powder would be dusted onto the exterior root surfaces using. for example, a particulate atomizer or sprayer prior to replanting of the tooth.
• osteoblasts bone, cementum and dentin are formed from cells termed osteoblasts, cementoblasts and dentinoblasts respectively. It is known that these same calcified materials are resorbed by cells termed osteoclasts, cementoclasts, and dentinoclasts. It also known that these blasts and clasts" all originate from cells known as osteosites, cementosites and dentinosites.
• physiologically compatible and soluble calcium phosphate compounds described above appear to provide an environment conducive to the growth of blasts and will stimulate the metamorphosis of clasts into sites to permit the further differentiation into the necessary blasts.
• a method for enabling the naturally functioning growth of at least one of the following: fibroblasts, odontoblasts, cementoblasts and osteoblasts comprising positioning a porous mass of a physiologically soluble and compatible calcium phosphate compound adjacent the calcified tissues of a tooth and in contact with a blood supply sufficient to permit the formation of a blood clot in said calcium phosphate compound.
• a method according to claim 1 wherein said calcium phosphate compound comprises a phase Ca,(- 4) 4.
• a method according to claim 1 wherein said calcium phosphate compound comprises B phase Ca,(- 4).-
• a method according to claim 1 wherein said calcium phosphate compound comprises a mixture of at least two of the following compounds: or phase Ca,(- PO,),; 3 phase Ca,(P0,),; and Cal-1P0 6.
• a method according to claim 1 for enabling the regeneration of calcified and peridontal tissue said method more particularly comprising the steps of:
• said calcium phosphate compound comprises B phase Ca,(- 4):-
• said calcium phosphate compound comprises a mixture of at least two of the following compounds: or phase Ca P0 8 phase Ca,(PO and CaHPO..
• said calcium phosphate compound is prepared by sintering together particles of said compound into a unitary body; then grinding said body into a grated particulate; then adding a vehicle to said powder in sufficient quantity to form a putty-like mixture for filling into said cavity.
• a method according to claim 1 for performing a pulp capping procedure which enables the formation of a dentinal bridge in a tooth comprising:
• a method according to claim 13 wherein said calcium phosphate compound comprises CaHPO,.
• said calcium phosphate compound comprises a phase Ca;(- 4):-
• a method for enabling the naturally functioning growth of at least one of the following: fibroblasts, odontoblasts, cementoblasts and osteoblasts comprising positioning a physiologically soluble and compatible calcium phosphate compound adjacent the calcified tissues of a tooth and in contact with a blood supply sufficient to permit the formation of a blood clot in said calcium phosphate compound said method more particularly comprising a root canal procedure for the apexification of an open apex tooth root said procedure comprising:
• a method according to claim 19 wherein said calcium phosphate compound comprises a phase Ca,(- 4):-
• a method according to claim 19 wherein said calcium phosphate compound comprises ⁇ 3 phase Ca 23.
• said calcium phosphate compound comprises a mixture of at least two of the following compounds: 01 phase Ca;(- P005 3 phase Ca,(PO and Cal-IP0 24.
• a procedure according to claim 19 wherein said calcium phosphate compound is also forcibly extruded out through the open tooth apex when being filled into said root canal.
• a method for enabling the naturally functioning growth of at least one of the following: fibroblasts, odontoblasts, cementoblasts and osteoblasts comprising positioning a physiologically soluble and compatible calcium phosphate compound adjacent the calcified tissues of a tooth and in contact with a blood supply sufficient to permit the formation of a blood clot in said calcium phosphate compound said method more particularly comprising a procedure for replanting an avulsed tooth. said procedure comprising:
• said calcium phosphate compound comprises a mixture of at least two of the following compounds: or phase Ca P0,; B phase Ca P0 and CaHPO

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• Health & Medical Sciences (AREA)
• Oral & Maxillofacial Surgery (AREA)
• General Health & Medical Sciences (AREA)
• Epidemiology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Plastic & Reconstructive Surgery (AREA)
• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Dental Preparations (AREA)
• Dental Prosthetics (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)

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Cited By (42)

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Citations (4)

• 1974
  • 1974-02-25 US US445678A patent/US3913229A/en not_active Expired - Lifetime
• 1975
  • 1975-01-21 GB GB2490/75A patent/GB1484781A/en not_active Expired
  • 1975-02-18 CA CA220,602A patent/CA1042801A/en not_active Expired
  • 1975-02-21 AU AU78422/75A patent/AU7842275A/en not_active Expired
  • 1975-02-24 FR FR7505658A patent/FR2261749B3/fr not_active Expired
  • 1975-02-24 BE BE153657A patent/BE825885A/xx not_active IP Right Cessation
  • 1975-02-24 DE DE19752507933 patent/DE2507933A1/de active Granted
  • 1975-02-24 CH CH225075A patent/CH604701A5/xx not_active IP Right Cessation
  • 1975-02-25 JP JP50022512A patent/JPS5813523B2/ja not_active Expired

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