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Biomedical subjects

T Karring

Publications and source records attributed to T Karring.

At least 19 recordsLinked to original sources
PubMed2005

Formation of human cementum following different modalities of regenerative therapy.

The aim of the present study was to compare newly formed cementum following different types of regenerative therapy in humans. Eighteen patients, each displaying one advanced intrabony defect around teeth scheduled for extraction, were included in this study. The defects were treated with either guided tissue regeneration (GTR), enamel matrix protein derivative (EMD), EMD plus bioactive glass, bovine-derived xenograft (BDX), BDX plus GTR, or BDX plus EMD. After healing, the teeth were removed together with their surrounding soft and hard tissues. Cellular content, presence of artifactual splits between the new cementum and the old one or the dentin surface, and thickness of the new cementum were evaluated. Irrespective of treatment, the new cementum was of a reparative, cellular, extrinsic and intrinsic fiber type. There were no differences in cementum thickness among treatments. These findings indicate that in humans, (a) the new cementum formed after different types of regenerative therapy was, irrespective of the treatment, of a reparative, cellular, extrinsic and intrinsic fiber type, and (b) the regenerative modality does not seem to influence the type of newly formed cementum.

Animals↗
PubMed2004

Healing of human intrabony defects following regenerative periodontal therapy with a bovine-derived xenograft and guided tissue regeneration.

The purpose of the present study was to histologically evaluate the healing of human intrabony defects following treatment with either a bovine-derived xenograft (BDX) and guided tissue regeneration (GTR) [BDX + GTR] or a bovine-derived xenograft mixed with collagen (BDX Coll) and GTR [BDX Coll + GTR]. Eight patients with chronic periodontitis and each with one very deep intrabony defect around a tooth scheduled for extraction were treated with either a combination of BDX + GTR (five patients) or with BDX Coll + GTR (three patients). The postoperative healing was uneventful in all eight cases. After a healing period of 6 months, the teeth or roots were extracted together with some of their surrounding soft and hard tissues and subsequently fixed in 10% buffered formalin. Following decalcification in EDTA, the specimens were embedded in paraffin and 8-microm histological sections were cut in the mesio-distal direction, parallel to the long axes of the teeth. The sections were alternatively stained with hematoxylin and eosin, van Giesson's connective tissue stain or with the Ladevig's connective tissue staining method and examined under the light microscope. Generally, formation of new cementum with inserting collagen fibers was found in seven out of the eight treated cases, whereas in the remaining case (treated with BDX + GTR) the healing was characterized by formation of a long junctional epithelium along the debrided root surface and no formation of cementum or bone. In the specimens demonstrating periodontal regeneration the new cementum was always of a cellular type. In most cases, the graft particles were surrounded by bone. In some areas, the bone tissue around the graft particles was connected by perpendicularly inserting collagen fibers to the newly formed cementum on the root surface. The epithelium downgrowth stopped always at the most coronal part of the newly formed cementum. No remnants of the membrane material were observed in any of the biopsies. Connective tissue encapsulation of the graft particles was rarely observed and was limited to the most coronal part of the defects. The findings of the present study provide evidence that treatment of intrabony defects with both BDX + GTR and BDX Coll + GTR may enhance periodontal regeneration in humans.

Alveolar Bone Loss↗
PubMed2003

Deproteinized bovine bone and gentamicin as an adjunct to GTR in the treatment of intrabony defects: a randomized controlled clinical study.

OBJECTIVES: To evaluate whether Bio-Oss used as an adjunct to guided tissue regeneration (GTR) improves the healing of 1- or 2-wall intrabony defects as compared with GTR alone, and to examine whether impregnation of Bio-Oss with gentamicin may have an added effect. MATERIAL AND METHODS: Sixty patients, with at least one interproximal intrabony defect with probing pocket depth (PPD) > or =7 mm and radiographic evidence of an intrabony component (IC) > or =4 mm, were treated at random with either a resorbable membrane (GTR), a resorbable membrane in combination with Bio-Oss impregnated with saline (DBB-), a resorbable membrane in combination with Bio-Oss impregnated with gentamicin (DBB+), or with flap surgery (RBF). RESULTS: All treatment modalities resulted in statistically significant clinical improvements after 1 year. Defects treated with GTR alone presented a probing attachment level (PAL) gain of 2.9 mm, a residual PPD (PPD12) of 4.9 mm, a radiographic bone level (RBL) gain of 3.1 mm, and a residual IC (IC12) of 2.7 mm. GTR combined with Bio-Oss did not improve the healing outcome (PAL gain: 2.5 mm; PPD12: 4.9 mm; RBL gain: 2.8 mm; IC12: 3.3 mm). Impregnation of the Bio-Oss with gentamicin 2% mg/ml resulted in clinical improvements (PAL gain: 3.8 mm; PPD12: 4.2 mm; RBL gain: 4.7 mm; IC12: 2.1 mm), superior to those of the other treatment modalities, but the difference was not statistically significant. Defects treated with only flap surgery showed the most inferior clinical response (PAL gain: 1.5 mm; PPD12: 5.1 mm; RBL gain: 1.2 mm; IC12: 4.2 mm) of all groups. CONCLUSION: The results failed to demonstrate an added effect of Bio-Oss implantation in combination with GTR on the healing of deep interproximal 1- or 2-wall, or combined 1- and 2-wall intrabony defects compared with GTR alone. Local application of gentamicin, on the other hand, improved the treatment outcome but not to an extent that it was statistically significant.

Absorbable Implants↗
PubMed2003

Gentamicin used as an adjunct to GTR.

OBJECTIVES: To evaluate in a discriminating "capsule" model whether local application of gentamicin may have an added effect on bone formation produced by Bio-Oss and guide tissue regeneration (GTR). MATERIAL AND METHODS: Thirty male 3-month-old Wistar rats were used. After elevation of muscle-periosteal flaps, a rigid hemispherical Teflon capsule, loosely packed with 0.025 g of Bio-Oss impregnated with 2 mg/ml gentamicin sulfate (Garamycin), was placed with its open part facing the lateral bone surface of the mandibular ramus (test) in one side of the jaw. A capsule filled only with Bio-Oss (control) was placed on the contralateral side of the jaw. After healing periods of 1, 2 and 4 months, groups of 10 animals were sacrificed and the specimens were processed for histological examination. The volumes of (1) the space created by the capsule, (2) newly formed bone, (3) Bio-Oss particles, (4) loose connective tissue, and (5) acellular space in the capsule were estimated by a point-counting technique in three to four histological sections of each specimen, taken by uniformly random sampling. RESULTS: The histological evaluation showed limited but increasing bone fill in the capsules from 1 to 4 months in both the test and control sides. After 4 months, the newly formed bone occupied 11.9% (CV: 0.39) of the space created by the capsules at the test sides versus 13.2% (CV: 0.41) at the control sides. There was no statistical significant difference between test and control specimens at any observation time (p>0.05). CONCLUSION: It is concluded that local application of gentamicin has no added effect on bone formation when combined with Bio-Oss and GTR.

Animals↗
PubMed2003

Osteogenesis by guided tissue regeneration and demineralized bone matrix.

AIM: To evaluate in a discriminating capsule model whether bone formation by guided tissue regeneration (GTR) may be influenced by concomitant implantation of demineralized bone matrix (DBM). MATERIALS AND METHODS: Thirty 4-month-old male albino rats of the Wistar strain were used in the study. Following surgical exposure of the mandibular ramus, a hemispherical, Teflon capsule (5.0 mm in diameter), loosely packed with a standardized amount of DBM, was placed with its open part facing the lateral bone surface of the ramus. At the contralateral side, an empty capsule was placed, serving as control. After healing periods of 15, 30, and 120 days, groups of 10 animals were sacrificed and 40-70 microm thick undecalcified sections of the capsules were produced. In the sections, the cross-sectional areas of (1) the space created by the capsule, (2) newly formed bone, (3) DBM particles, (4) loose connective tissue as well as the (5) height of the capsules, and (6) that of the newly formed bone were measured. RESULTS: Increasing bone fill was observed in both test and control sites from 30 to 120 days. After 30 days of healing, the mean amount of bone was approx. 3% of the cross-sectional area of the capsules at the test sites while it was 8% in the control sites (p<0.05). However, no statistically significant differences were observed between the test (46%) and control (64%) sites after 120 days regarding any of the measured parameters (p>0.05). The newly formed bone in the DBM group at 120 days, on the other hand, appeared more dense than that in the control capsules. CONCLUSION: DBM used as an adjunct to GTR did not provide any added effect on bone formation but increased the density of the newly formed bone.

Animals↗
PubMed2003

Wound healing of degree III furcation involvements following guided tissue regeneration and/or Emdogain. A histologic study.

BACKGROUND: The use of enamel matrix proteins (EMD) has been recently introduced as a new treatment alternative for periodontal regeneration. However, no histological studies are available investigating the effect of EMD in the treatment of degree III furcation involvements. OBJECTIVES: The aim of this study was to evaluate the healing of mandibular degree III furcation involvements histologically following treatment with guided tissue regeneration (GTR), EMD and a combination of EMD and GTR. MATERIAL AND METHODS: Degree III furcation involvements were surgically created at the teeth 36, 37, 46, 47 in three monkeys (Macaca fascicularis). Spontaneous healing of the defects was prevented by placing impression material into the defects. After 6 weeks, full-thickness flaps were elevated at the buccal and lingual aspect of the experimental teeth. Following removal of all granulation tissue from the furcation defects, scaling/root planing and conditioning of the root surfaces with 24% EDTA gel, the defects were treated with one of the following treatment modalities: (i) EMD, (ii) GTR or (iii) a combination of EMD and GTR. The defects serving as control did not receive any treatment, except from complete coverage with coronally displaced flaps. After 5 months of healing, the animals were killed and perfused with 10% buffered formalin for fixation. The experimental teeth with surrounding tissues were dissected free, decalcified in EDTA, dehydrated and embedded in paraffin. 8 microm thick histological sections were cut and stained and subsequently examined under the light microscope. RESULTS: The histological analysis revealed that with GTR or combined EMD and GTR treatment, new attachment formation (new cementum with inserting collagen fibers) had occurred on almost the entire circumference of the furcation and new bone was almost filling the defect in the situations where the membrane was not exposed. The sites treated only with EMD exhibited new attachment and new bone formation to a varying extent, while the control sites presented only limited new attachment and bone formation. CONCLUSION: The results provided histological evidence suggesting that both GTR and EMD may result in true periodontal regeneration, and suggest that this type of healing might be favored by such treatments in comparison with flap surgery.

Animals↗
PubMed2003

Denaturation of demineralized bone matrix significantly reduces bone formation by guided tissue regeneration.

AIM: To examine in a discriminating capsule model whether denaturation of demineralized bone matrix (DBM) by heating may influence bone formation. MATERIALS AND METHODS: DBM was produced from the long bones of rats. Half the portion of DBM was denatured by heating in distilled water for 20 min at temperatures between 70 degrees C and 90 degrees C. Prior to the study, the destruction of the osteoinductive properties of the DBM was confirmed in three rats following intramuscular implantation. Thirty, 4-month-old, male albino rats of the Wistar strain were used in the study. Following surgical exposure of the mandibular ramus, a hemispherical Teflon capsule (internal diameter = 5.0 mm) was placed, with its open part facing the lateral aspect of the ramus. On one side (test side), the capsule was loosely packed with denatured DBM, while on the contralateral side, serving as control, the capsule was loosely packed with the same amount of non-denatured DBM. After healing periods of 30, 60, and 120 days, groups of 10 animals were killed and 40-70 microm thick undecalcified sections of the capsules were produced. Three sections from each specimen, representing the mid-portion of the capsule, were subjected to histological analysis and computer-assisted planimetric measurements. RESULTS: Increasing amounts of newly formed bone were observed in both test and control capsules during the experimental period. At 4 months, the new bone formed in the control capsules occupied 46.7% of the cross-sectional area of the capsules, while it was only 19.1% in the test capsules (P<0.05). CONCLUSION: Denaturation of DBM by heating significantly reduces bone formation by guided tissue regeneration.

Animals↗
PubMed2003

Evaluation of a cell-permeable barrier for guided tissue regeneration combined with demineralized bone matrix.

AIM: To evaluate whether bone formation by guided tissue regeneration (GTR) and demineralized bone matrix (DBM) can be enhanced by the use of a cell-permeable Teflon barrier allowing the penetration of undifferentiated mesenchymal cells from the surrounding soft tissues. MATERIAL AND METHODS: DBM was produced from the long bones of rats, and its bone-inductive properties were tested in three rats prior to the study by intramuscular implantation. Thirty, 4-month-old, male albino rats of the Wistar strain were used. Following surgical exposure of the mandibular ramus, a cell-permeable Teflon capsule, loosely packed with DBM, was placed with its opening facing the lateral surface of the ramus (test side). At the contralateral side, serving as control, a non-perforated (cell-occlusive) Teflon capsule, loosely packed with the same amount of DBM, was placed. After healing periods of 30, 60, and 120 days, groups of 10 animals were killed, and 40-70 microm thick undecalcified sections of the capsules were produced. RESULTS: Computer-assisted planimetric measurements on the histological sections disclosed similar amounts of newly formed bone in both test and control capsules. After 4 months, the new bone in the control capsules occupied 45.0% of the cross-sectional area of the capsule, while it was 50.5% in the test capsules. This difference was not statistically significant (P<0.05). CONCLUSION: Similar amounts of bone formed in cell-permeable and cell-occlusive capsules grafted with DBM, suggesting that invasion of undifferentiated mesenchymal cells from the surrounding soft tissues into the barrier-protected area is unnecessary for bone formation with GTR.

Animals↗
PubMed2001

Role of chitin beads in the formation of jaw bone by guided tissue regeneration. An experiment in the rat.

It has been reported that local application of bone grafts or synthetic bone substitutes (filler materials) may favour bone formation when used in combination with guided tissue regeneration (GTR). Therefore, the aim of the present investigation was to evaluate the effect of application of chitin beads (a bioabsorbable natural polymer) as a bone substitute in bone formation by GTR. The experiment was carried out in 25 rats. The mandibular ramus was exposed on one side after elevation of a muscle-periosteal flap, and a teflon capsule filled with chitin beads (2.0 mm in diameter) was placed with its opening facing the lateral aspect of the ramus. On the contralateral side of the jaw, serving as control, an empty teflon capsule was placed in the same manner. Groups of 5 animals were sacrificed at 7, 15, 30, 60 and 120 days following capsule placement. Histological analysis demonstrated that the amount of newly formed bone was similar in both experimental and control specimens, amounting to approximately 3% of the central/largest, cross-sectional area created by the capsule at 15 days, and to approximately 9% of this area at 30 days following capsule placement. At 60 and 120 days, however, the amount of newly formed bone observed in the control specimens was twice as large as that observed in the test specimens, amounting to approximately 31% of the cross-sectional area created by the capsule at 60 days, and to approximately 45% at 120 days. It is concluded that, although chitin beads (2.0 mm in diameter) are biocompatible, their presence retards bone formation in the model system used.

Absorbable Implants↗
PubMed2001

Deproteinized bovine bone used as an adjunct to guided bone augmentation: an experimental study in the rat.

BACKGROUND: Promising results have been reported following treatment of periodontal and peri-implant bone defects with deproteinized bovine bone grafts, but their influence on bone formation has not been clarified. PURPOSE: The goal of this study was to examine whether implantation of deproteinized bovine bone (Bio-Oss, Geistlich AG, Wolhusen, Switzerland) influences bone formation when used as an adjunct to guided bone augmentation (GBA). MATERIALS AND METHODS: A rigid, hemispherical, Teflon capsule was loosely packed with a standardized quantity of Bio-Oss and placed with its open part facing the lateral surface of the mandibular ramus (test) in 30 rats. At the contralateral side of the jaw, an empty capsule was placed (control). Groups of 10 animals were sacrificed after 1, 2, and 4 months. The volumes of the space created by the capsule and of the (1) newly formed bone, (2) remaining Bio-Oss particles, (3) soft connective tissue, and (4) acellular space in the capsule were estimated by a point-counting technique in three or four histologic sections, taken by uniformly random sampling. RESULTS: Bone formation at 1 month was limited in both tests and controls. After 2 months, the mean volume of the newly formed bone occupied 9.0% of the space created by the capsule in the test specimens compared with 23.8% in the control specimens (p < .01). After 4 months, the respective figures were 11.6% (tests) versus 38.7% (controls) (p < .01). CONCLUSION: It can be concluded that Bio-Oss, used as an adjunct to GBA, interferes with bone formation.

Animals↗
PubMed2000

Healing of fenestration-type defects following treatment with guided tissue regeneration or enamel matrix proteins. An experimental study in monkeys.

The aim of the present study was to evaluate histologically in monkeys the healing in acute fenestration-type defects following treatment with guided tissue regeneration (GTR) or enamel matrix proteins (EMD). Standardized "critical size" fenestration-type defects were produced surgically at the vestibular aspect of teeth 13, 23, 33, 43 in three monkeys (Macaca fascicularis). The vestibular bone plates were removed and the root surfaces were debrided by means of hand instruments in order to completely remove the root cementum. Following root conditioning with ethylenediaminetetraacetate (EDTA), the defects were treated using one of the following therapies: (1) GTR, (2) EMD, or (3) control (coronally repositioned flaps). After 5 months the animals were killed and perfused with 10% buffered formalin for fixation. Specimens containing the defects and surrounding tissues were dissected free, decalcified in EDTA, and embedded in paraffin. Eight-micrometer-thick step serial histological sections were cut in a vestibulo-oral direction, stained with hematoxylin and eosin or oxone-aldehyde-fuchsin-Halmi, and subsequently examined under the light microscope. The results showed that, in the defects treated with GTR, a new connective tissue attachment (i.e., new cementum with inserting collagen fibers) and new bone formation had consistently occurred, whereas, in the defects treated with EMD or with coronally repositioned flaps, new attachment and new bone reformed to a varying extent. The quality of the cementum did not differ after EMD, GTR, or flap surgery. It was concluded that GTR treatment with bioresorbable membranes seems to predictably promote new attachment and new bone formation, whereas the application of EDTA or EMD may also enhance periodontal healing to a certain extent. Further studies with higher numbers of animals and defects are needed in order to definitely clarify the effect of root surface conditioning with EDTA and EMD on periodontal healing.

Absorbable Implants↗
PubMed2000

Treatment of intrabony defects with guided tissue regeneration and enamel-matrix-proteins. An experimental study in monkeys.

BACKGROUND: Enamel matrix proteins (EMD) have recently been introduced in regenerative periodontal treatment. However, no histological data are yet available concerning the effect of treating intrabony periodontal defects with EMD, and no histological comparisons have been made comparing the result of treatment of intrabony defects with EMD with that of the treatment with guided tissue regeneration (GTR). AIM: Therefore, the aim of the present study was to evaluate histologically in monkeys the effect of treating intrabony defects with EMD, GTR or combined EMD and GTR. METHOD: Intrabony periodontal defects were produced surgically at the distal aspect of teeth 14, 11, 21, 24, 34, 31, 41 and 44 in 3 monkeys (Macaca fascicularis). In order to prevent spontaneous healing and to enhance plaque accumulation metal strips were placed into the defects. After 6 weeks the defects were exposed using a full-thickness flap procedure. The granulation tissue was removed and the root surfaces were debrided by means of hand instruments. Subsequently, the defects were treated using one of the following therapies: (i) GTR, (ii) EMD, or (iii) combination of EMD and GTR. The control defects were treated with coronally repositioned flaps. After 5 months, the animals were sacrificed and perfused with 10% buffered formalin for fixation. Specimens containing the defects and surrounding tissues were dissected free, decalcified in EDTA and embedded in paraffin. 8 microm thick histological sections were cut and stained and subsequently examined under the light microscope. RESULTS: In the control specimens, the healing was characterized by a long junctional epithelium and limited periodontal regeneration (i.e., new periodontal ligament, new cementum with inserting connective tissue fibers and new bone) in the bottom of the defect. The GTR-treated defects consistently presented periodontal regeneration when the membranes were not exposed whereas the sites treated only with EMD presented regeneration to a varying extent. The combined therapy did not seem to improve the results. CONCLUSION: It can be concluded that all 3 treatment modalities favor periodontal regeneration.

Alveolar Bone Loss↗
PubMed2000

Regeneration of the sagittal suture by GTR and its impact on growth of the cranial vault.

The aim of this study was to investigate the effect of bone grafting, suture transplantation, and guided tissue regeneration (GTR) treatment on healing of craniectomy defects involving the sagittal cranial suture and on the growth of the cranial vault. Fifty 4-week-old rats were included in the study. A 5.0 mm wide trephine defect was created with its midline corresponding to the sagittal cranial suture between the coronal and occipital cranial vault sutures. The animals were randomly allocated to five groups of 10 animals. Group A: The cranial defect was left untreated. Group B: An occipital bone graft was placed into the cranial defect. Group C: A cranial bone graft including a portion of the frontal suture was placed in the cranial defect. Group D: The cerebral and galeal aspect of the defect were covered with an e-PTFE membrane. Group E: The animals were sham-operated, no defect was created. In all animals, two gutta-percha points were placed demarcating the lateral borders of the parietal bones. Histological analysis at 4 months following surgery showed that the untreated cranial defects healed with fibrous connective tissue. The bone-grafted defects healed partially with bone and connective tissue in the periphery of the bone graft. The healing of suture-grafted defects resembled that of the bone-grafted defects, since the transplanted suture became completely obliterated with bone. The membrane-treated defects healed with bone and a suture-like tissue resembling the sagittal suture of the sham-operated controls. Cephalometric measurements demonstrated that membrane-treated and sham-operated control animals exhibited significantly more (P < 0.05) coronal growth (approximately 1.2 mm) than that of the remaining three groups of animals (approximately 0.7 mm). These findings were supported by the craniometry measurements demonstrating that sham-operated control and membrane-treated specimens presented significantly more cranial width than that of the remaining groups of animals (P < 0.05). It can be concluded that complete osseous healing, creation of a new sagittal suture, and increased cranial growth can be achieved by the treatment of craniectomy defects with the GTR technique.

Animals↗
PubMed2000

Clinical evaluation of subgingival application of metronidazole 25%, and adjunctive therapy.

The effect of topical application of a metronidazole gel (ELYZOL DENTAL GEL), and adjunctive therapy in the treatment of adult periodontitis was assessed clinically. A single, masked examiner performed clinical assessments. Fourteen patients were involved, each one received four different treatments including control, and the four treatments were randomly applied to at least one tooth in each quadrant for each patient in a comparative split-mouth design. Clinical examinations were carried out before treatment and 90 days after treatment. All patients had at least one tooth in each quadrant with probing pocket depth of > or = 5mm. The four treatment groups were: (I) One session of one hour of scaling and root planning, (II) metronidazole 25% dental gel (ELYZOL DENTAL GEL) applied on day 0 and day 7, (III) scaling adjunctive to metronidazole 25%, and (IV) No treatment. Instruction in oral hygiene was given to all subjects at base line examination. At the end of the study (day 90), all groups had statistically significant improvement in probing pocket depth (P < 0.02), and in plaque and bleeding indices (P < 0.05) when compared to day 0. However, group III had statistically significantly greater improvement (P < 0.03) in probing pocket depth than groups I, II and IV. Both groups I and II had statistically significantly greater improvement (P < 0.05) in probing pocket depth than control group. On the other hand, both groups were not statistically significantly different from each other in probing pocket depth improvement. It is suggested that topical Elyzol treatment may improve periodontal health as well as subgingival scaling and root planning therapy, and adjunctive treatment could obtain an additional therapeutic effect.

Administration, Topical↗
PubMed2000

Regenerative periodontal therapy.

Regenerative periodontal therapy comprises procedures which are specially designed to restore parts of the tooth supporting apparatus which have been lost due to periodontitis. A procedure must fulfill certain criteria to be considered a therapy which encourages regeneration. This paper discusses a variety of surgical approaches including root surface conditioning, the placement of bone garfts or bone substitute implants and the use of organic or synthetic barrier membranes (GTR). Evidence is presented that regenerative surgery utilising the GTR principle fulfills all the criteria required of a surgical procedure to be considered a procedure leading to periodontal regeneration.

Animals↗
PubMed1999

Long-term stability of jaw bone tuberosities formed by "guided tissue regeneration".

The aim of the present study was to evaluate whether bone tuberosities produced by GTR on the lateral surface of the mandibular ramus in rats are stable on a long-term basis. Thirty male 6-month-old albino rats of the Wistar strain were used in the study. Tissue flaps were elevated on the lateral aspect of the mandibular ramus. The periosteum was preserved (P+) on one side of the jaw while the bone was denuded (P-) on the other. A rigid, non-porous oval-shaped teflon capsule was placed on both sides with its opening facing the ramus. Six months following surgery, 10 rats were sacrificed and prepared for histology while the remaining 20 rats were subjected to a second operation during which the capsules were removed. Standardized radiographs, taken immediately before and after removal of the capsule and after 3, 6, 9 and 12 months, were subjected to planimetric measurements and subtraction radiography. Ten animals were sacrificed and prepared for histological analysis after 6 months following removal of the capsules and the remaining 10 animals after 12 months. Histology revealed that at 6 months after the placement of the capsules, 17 were completely filled with new bone. The remaining 3 capsules which were displaced exhibited only partial bone fill. The radiographic analysis revealed that after 6 months 98.6 +/- 7.6% (mean +/- SD) in average of the cross-sectional area created by the capsules was filled with new bone. Within 3 months after removal of the capsules a slight resorption of the new bone had occurred, thereby reducing the area of the bone tuberosities by 4 to 8%. No further resorption of the bone tuberosities took place from 3 to 12 months. These observations indicating that new bone produced by GTR is stable on a long-term basis, may question the general belief that non-functional bone will resorb over time.

Animals↗
PubMed1999

Presence of oxytalan fibers in human regenerated periodontal ligament.

The aim of the present study was to investigate whether oxytalan fibers are formed in the regenerated human periodontal ligament. 6 patients, each of them exhibiting an advanced intrabony defect, were treated with a bioresorbable membrane according to the GTR-principle. Following a healing period of 6 months, the teeth were extracted together with their surrounding soft and hard tissues and subsequently fixed in 10% buffered formalin. Following decalcification in EDTA, the specimens were embedded in paraffin and 8-microm histological sections were cut in the mesio-distal direction, parallel to the long axes of the teeth. The sections were stained with hematoxylin and eosin, or with the oxone-aldehyde-fuchsin-Halmi staining method and examined in the light microscope. A regenerated periodontal ligament containing newly-formed oxytalan fibers was observed in all specimens. Many of them inserted into the newly formed cementum on the root surface. It is concluded that oxytalan fibers are formed de novo in human regenerated periodontal ligament tissue.

Absorbable Implants↗