Periodontal regeneration composition and method of using same

#The invention relates to a bone growth and periodontal structure regeneration material, and method for treating periodontal disease.

#Periodontal disease occurs when bacteria colonize the sulcus space between the teeth and gingiva. The bacteria cause inflammation. The inflammation destroys the gingival epithelial lining and epithelial attachment to the tooth. The inflammation then progresses down the tooth root toward the apex of the root and destroys periodontal structure and bone. As periodontal disease progresses open pockets develop between the tooth and the gingiva. A dentist can determine the presence and extent of periodontal disease using a probe to measure the depth of pockets between each tooth and gingiva. X-rays can reveal the extent of any bone loss.

#A common surgical procedure has been widely used to treat bone loss caused by periodontal disease. In this procedure the periodontist uses a scalpel to incise the gingiva and reflects it back to expose the tooth root and bone. Then he removes the irregular shaped bone with hand instruments or rotary instruments, surgically removes granulation tissue and gingiva, cleans the site and places a bone regeneration material into osseous defects that remain in the bone. Guided Tissue Regeneration barriers are placed over bone regeneration material in deeper osseous defects. He then sutures the gingiva around the tooth. Then the gingiva, epithelial attachment, bone, and periodontal ligament between the tooth and bone reform. While this procedure has been effective, incisions in the gingiva cause patient discomfort, pain, swelling, gingival recession, sensitive teeth, a long healing time, and increase the possibility of infection. The goal of visualization of the roots, removal of granulation tissue, and excision of damaged gingiva utilizing traditional incision periodontal surgery on a normal compliment of 28 teeth requires a cumulative incision length of 41 to 46 inches. The extensive cumulative length of surgical incisions wears down the scalpel cutting edge. It is common surgical practice to use and discard between 4 to 10 Bard Parker #15 surgical scalpel blades for each patient. To reposition all of the surgically loosened gingiva requires between 4 to 8 suture packets of 18 inch suture. The volume of granulation tissue and gingiva removed is approximately 2 to 5 cc. Estimated blood loss varies 2 cc to 18 cc per patient. The post-surgical period requires strong analgesics to maintain pain relief. At the 2 week suture removal appointment, the gingival incisions are only about 50% healed, and require 2 to 4 additional weeks for final healing. The period of painful, sensitive, and bleeding gingiva lasts 3 to 4 weeks after the surgery. After this struggle to gain periodontal health, the patient now faces gingival recession with exposed sensitive roots resulting from granulation and gingiva removal. Cosmetic difficulties result from the loss of the interdental gingiva that creates dark spaces between the teeth. The exposure of the margins of facings and crowns often requires replacement to correct cosmetic deficiencies.

#FIG. 1 is a front view of a healthy tooth.

#FIG. 2 is a front view of a tooth in a patient experiencing periodontal disease.

#FIG. 3 is a front view of a tooth in a patient having advanced periodontal disease and bone loss.

#As can be seen in FIG. 1 a tooth 2 has a crown 3 and root 4. The alveolar bone 8 surrounds the root 4. There is a periodontal ligament 10 around much of the root 4 and gingiva 12 surrounds the upper part of the root and the base of the crown 3. There is a pocket 14 between the gingiva 12 and the tooth 2. In a healthy tooth shown in FIG. 1 this pocket 14 is very shallow, typically one to three millimeters. Bacteria colonize the pocket. The bacteria cause the pocket 14 to deepen as shown in FIG. 2. As periodontal disease progresses the bacteria cause inflammation that destroys the ligament and bone creating depressions 18 in the bone shown in FIG. 3.

#The conventional way of treating advanced periodontal disease is to create incisions to reflect the gingiva 12, remove the damaged bone with hand instruments or sand area 18 with rotary burs, remove all debris from the sanding, place a bone growth material adjacent the sanded bone surfaces and suture the gingiva. The standard procedure for deeper osseous defects is to place expensive, and very difficult to manipulate, Guided Tissue Regeneration barriers over the bone regeneration material prior to suturing. I provide a method and material that does not involve incisions in the gingiva. Instead a bone growth material finely ground and mixed with fine collagen particles is injected into the pocket through a syringe. I abrade the root surface and inner surface of the gingiva first with a dental bur. I observed improved bone and periodontal structure regeneration if I did not rinse the abraded particles out of the pocket. Tooth dentin is a natural source of bone morphogenic protein and I utilize this source to promote bone generation. This failure to rinse is contrary to present dental practice. Standard periodontal practice is to completely clean the pocket of all abraded bone and to remove all granulation tissue. To abrade the root and gingival surfaces I simply place the dental bur into the pocket, but do not incise the gums. After abrading, specially designed gauze is placed into the 1-1.5 mm created space to both distend the pocket and create hemostasis with or without chemicals. I prefer to provide three sizes of gauze strips of 5 mm, 7.5. mm and 10 mm wide and 10 cm in length. As an additional use, the gauze can carry and place antibacterial materials, antibiotics, collagen, bone growth substances, or any type of root conditioning materials. Sufficient time is allowed for hemostasis, distention, and the placed materials to function as designed, then the gauze 15 is removed. As shown in FIG. 4, after abrading I inject a periodontal structural regeneration composition 20 into the pocket 14 through a syringe 22 and needle 24. This composition contains fine particles of bone growth material and free collagen particles all sized to be less than 1 mm in diameter. Free collagen particles are not cross-linked and are available to speed healing. The collagen may be small fibrils or a gel containing fibrillar collagen. A small amount of sterile saline or other liquid may be added. I prefer to use an 18 gauge needle because larger needles do not permit access to the small pockets found around the smaller anterior teeth. A 16 gauge needle could be used for treating molars suffering periodontal disease. Because an 18 gauge needle is needed to treat the anterior teeth, the particles in the periodontal structure regeneration composition 20 must be small enough to pass through an 18 gauge needle without clogging. Because the particles are so small the periodontal structure regeneration composition 20 looks like a gel as it exits the needle. This composition mixes with abraded root particles 17 in the pocket. Sufficient periodontal structure regeneration composition 20 is injected to fill the pocket as shown in FIGS. 4 and 5. The gingiva 12 then rebounds from the distension and moves back toward the tooth. Because the composition is injected into the periodontal pocket through a needle the viscosity has to be sufficient to pass through the needle but viscous enough to remain in the pocket. Some composition is forced from the pocket when the gingiva rebounds or returns to its normal position. But, most of the periodontal structure regeneration composition remains in the pocket. However, the viscosity of the composition that allows easy passage through the needle enables further migration from the periodontal pocket during normal movement of the mouth. To prevent that migration, it is preferred that a thickener be added to the composition, or that the composition be subjected to a brief infusion of energy, preferably but not exclusively by microwave radiation. A microwave exposure at power setting high for 20-40 seconds can be used. The composition will thicken a few minutes after being microwaved, allowing time for injection before the viscosity increases. The thickener or infusion of energy increases the viscosity of the composition after the composition has been injected into the periodontal pocket. The increase in viscosity is sufficient to prevent or retard migration or leakage of the composition from the pocket after the gingiva has rebounded to a relaxed position. Yet, the thickener does not cause the composition to form a rigid solid. The thickener also should not be a material that reacts with the collagen or causes the collagen in the composition to crosslink. The thickener must also be a physiologically compatible compound which does not injure or cause adverse reactions by the human body. This compound could be a liquid above normal body temperature and solidify at or below normal body temperature. The solidification of the thickener will increase the viscosity of the composition that is in the periodontal pocket but not cause the entire composition to become solid. This type of thickener could be an oligosaccharide such as certain polyethylene glycol compositions, that function this way. Another thickener that could be used is a chemical compound that slowly forms slightly soluble salts with one or more components of the composition, thus thickening the composition by giving it a larger percentage of solids after injection into the pocket. One could also put an adhesive in the composition that hardens in the presence of a catalyst, heat or light. There are polyurethanes which will set and then degrade over time. Certain silicones could also be used. Another method of thickening is formulating a composition that undergoes a phase change near physiological temperature to provide thickening. If this composition forms a eutectic mixture (solid and liquid (solution) phases existing in equilibrium) near physiological temperature, the cooling of a heated composition in the periodontal pocket would aid in prevention of the composition from migrating out of the periodontal pocket. Yet, another possibility is to use a hydrogel, corn starch or similar material that absorbs water and thereby thickens the composition. It is possible that this type of additive could draw water from tissue surrounding the periodontal pocket. For that reason only small amounts of this additive should be used, and the procedure may include putting water into the periodontal pocket immediately before injecting the composition. Those skilled in the art should recognize that other materials activated by air, heat, light or a catalyst could also be used as a thickener. Over time the periodontal regeneration composition causes both gingival growth, bone growth, and formation of a new epithelial attachment. Depending upon the extent of the disease, the teeth and bone will return to their healthy status shown in FIG. 1 in about 3 to 12 weeks.

#In an alternative embodiment a thickener is not provided in the composition. When that composition is used, I prefer to apply an adhesive 26 over the pocket to eliminate any pain or discomfort, to stop any bleeding, to keep the regeneration material in place, and to prevent foreign material from entering the pocket and dislodging the regeneration material. However, I have found that bone regeneration and healing occurs even when no adhesive is used. I prefer to use butyl cyanoacrylate as the adhesive because this material cures with water. Another suitable water curable adhesive is 2-Octyl Cynoacrylate sold by Johnson & Johnson under the trademark DERMABOND. One could also use an adhesive that cures when exposed to light. Dentistry now uses polymers for filling cavities that cure when exposed to blue light. There are also adhesives that cure when exposed to ultraviolet light that could be used. However, far too many eye injuries caused by ultraviolet light have resulted in a general reluctance to use ultraviolet light in dentistry. There are adhesives that cure upon exposure to visible light which should be useful in this procedure. Other water curable adhesives, auto-curing adhesives, heat cured adhesives and reactive-component cure adhesives may also be acceptable.