Tissue healing of immediate implant placement in extraction sockets with titanium versus zirconium oxide implants : an experimental study in the beagle dog

Tese de doutoramento, Medicina Dentária (Periodontologia), Universidade de Lisboa, Faculdade de Medicina Dentária, 2016

Hard tissue formation adjacent to implants of various size and configuration immediately placed into extraction sockets: an experimental study in dogs

Objectives To evaluate the influence of implant size and configuration on osseointegration in implants immediately placed into extraction sockets. Material and methods Implants were installed immediately into extraction sockets in the mandibles of six Labrador dogs. In the control sites, cylindrical transmucosal implants (3.3 mm diameter) were installed, while in the test sites, larger and conical (root formed, 5 mm diameter) implants were installed. After 4 months of healing, the resorptive patterns of the alveolar crest were evaluated histomorphometrically. Results With one exception, all implants were integrated in mineralized bone, mainly composed of mature lamellar bone. The alveolar crest underwent resorption at the control as well as at the test implants. This resorption was more pronounced at the buccal aspects and significantly greater at the test (2.7 +/- 0.4 mm) than at the control implants (1.5 +/- 0.6 mm). However, the control implants were associated with residual defects that were deeper at the lingual than at the buccal aspects, while these defects were virtually absent at test implants. Conclusions The installment of root formed wide implants immediately into extraction sockets will not prevent the resorption of the alveolar crest. In contrast, this resorption is more marked both at the buccal and lingual aspects of root formed wide than at standard cylindrical implants. To cite this article:Caneva M, Salata LA, de Souza SS, Bressan E, Botticelli D, Lang NP. Hard tissue formation adjacent to implants of various size and configuration immediately placed into extraction sockets: an experimental study in dogs.Clin. Oral Impl. Res. 21, 2010; 885-895.doi: 10.1111/j.1600-0501.2010.01931.x.

Influence of implant positioning in extraction sockets on osseointegration: histomorphometric analyses in dogs

Aim To evaluate the influence of implant positioning into extraction sockets on osseointegration. Material and methods Implants were installed immediately into extraction sockets in the mandibles of six Labrador dogs. In the control sites, the implants were positioned in the center of the alveolus, while in the test sites, the implants were positioned 0.8 mm deeper and more lingually. After 4 months of healing, the resorptive patterns of the alveolar crest were evaluated histomorphometrically. Results All implants were integrated in mineralized bone, mainly composed of mature lamellar bone. The alveolar crest underwent resorption at the control as well as at the test sites. After 4 months of healing, at the buccal aspects of the control and test sites, the location of the implant rough/smooth limit to the alveolar crest was 2 +/- 0.9 mm and 0.6 +/- 0.9 mm, respectively (P < 0.05). At the lingual aspect, the bony crest was located 0.4 mm apically and 0.2 mm coronally to the implant rough/smooth limit at the control and test sites, respectively (NS). Conclusions From a clinical point of view, implants installed into extraction sockets should be positioned approximately 1 mm deeper than the level of the buccal alveolar crest and in a lingual position in relation to the center of the alveolus in order to reduce or eliminate the exposure above the alveolar crest of the endosseous (rough) portion of the implant. To cite this article:Caneva M, Salata LA, de Souza SS, Baffone G, Lang NP, Botticelli D. Influence of implant positioning in extraction sockets on osseointegration: histomorphometric analyses in dogs.Clin. Oral Impl. Res. 21, 2010; 43-49.

Filling of extraction sockets with autogenous bone in cats

OBJETIVO: Avaliar a regeneração óssea de alvéolos dentais de gatos após enxertia. MÉTODOS: Dezoito gatos adultos, distribuídos em três grupos de 6 animais cada, foram submetidos a extração do canino mandibular direito ou esquerdo. No grupo 1, controle, o alvéolo foi deixado vazio. No grupo 2, o alvéolo foi preenchido com osso esponjoso autógeno do osso ilíaco e no grupo 3, com raspa de osso cortical do osso ilíaco. Os animais foram submetidos à eutanásia 6 semanas após a cirurgia. RESULTADOS: Nas radiografias realizadas no pós-operatório imediato na projeção ventrodorsal observou-se uma área de radiolucência correspondente ao local da alveolectomia e extração dentária. Diminuição da radiolucência foi verificada nas radiografias realizadas seis semanas após a cirurgia. Nos cortes histológicos verificou-se a presença de trabéculas ósseas. A porcentagem de tecido ósseo esponjoso presente nos alvéolos dentais foi quantificada por exames histométricos. Não houve diferença estatisticamente significante entre os grupos (Teste de Kruskal-Wallis p > 0.05) (grupo 1: 52,54 ± 15,4; grupo 2: 50,51 ± 5,01; grupo 3: 51,85 ± 9,52). CONCLUSÃO: Os alvéolos dentais de gatos preenchidos com osso esponjoso autógeno ou raspa de osso cortical autógeno apresentaram regeneração óssea similar àquela observada no grupo controle, após um período de observação de seis semanas.

Short implants (6 mm) installed immediately into extraction sockets: An experimental study in dogs

Aim: To evaluate the effect of implant length (6 mm vs. 11 mm) on osseointegration (bone-toimplant contact) of implants installed into sockets immediately after tooth extraction.Material and methods: In six Labrador dogs, the pulp tissue of the mesial roots of P-3(3) was removed and the root canals were filled. Flaps were elevated bilaterally, the premolars hemisectioned and the distal roots removed. Recipient sites were prepared in the distal alveolus and a 6 mm or an 11 mm long implant was installed at the test and control sites, respectively. Non-submerged healing was allowed. After 4 months of healing, block sections of the implant sites were obtained for histological processing and peri-implant tissue assessment.Results: No statistically significant differences were found between test and control sites both for hard and soft tissue parameters. The bone-to-implant contact evaluated at the apical region of the implants was similar as well. Although not statistically significant, the location of the top of the bony crest at the buccal aspect was more apical in relation to the implant shoulder at the test compared with the control sites (2.0 +/- 1.4 and 1.2 +/- 1.1 mm, respectively).Conclusions: Shorter implants (6 mm) present with equal osseointegration than do longer implants (11 mm).

Bone regeneration at implants placed into extraction sockets of maxillary incisors in dogs

AimTo compare the influence of autologous or deproteinized bovine bone mineral as grafting material on healing of buccal dehiscence defects at implants installed immediately into the maxillary second incisor extraction socket in dogs.Material and methodsIn the maxillary second incisor sockets of 12 Labrador dogs, implants were installed immediately following tooth extraction. A standardized buccal defect was created and autologous bone particles or deproteinized bovine bone mineral were used to fill the defects. A collagen membrane was placed to cover the graft material, and the flaps were sutured to fully submerge the experimental areas. Six animals were sacrificed after 2 months, and six after 4 months of healing. Ground sections were obtained for histological evaluation.ResultsAfter 2 months of healing, all implants were osseointegrated. All buccal dehiscence defects were completely filled after 2 months irrespective of the augmentation material (autologous bone or Bio-Oss (R)) applied. Bone-to-implant contact (BIC) on the denuded implant surfaces was within a normal range of 30-40%. However, the newly formed tissue at 2 months was partially resorbed (> 50% of the area measurements) after 4 months.ConclusionsApplying either autologous bone or deproteinized bovine bone mineral to dehiscences at implants installed immediately into extraction sockets resulted in high degree of regeneration of the defects with satisfactory BIC on the denuded implant surface.To cite this article:De Santis E, Botticelli D, Pantani F, Pereira FP, Beolchini M, Lang NP. Bone regeneration at implants placed into extraction sockets of maxillary incisors in dogs.Clin. Oral Impl. Res. 22, 2011; 430-437.

Alveolar process preservation at implants installed immediately into extraction sockets using deproteinized bovine bone mineral - an experimental study in dogs

Aim To evaluate the soft tissue and the dimensional changes of the alveolar bony crest at sites where deproteinized bovine bone mineral (DBBM) particles, concomitantly with the placement of a collagen membrane, were used at implants installed into sockets immediately after tooth extraction. Material and methods The pulp tissue of the mesial roots of 3P3 was removed in six Labrador dogs, and the root canals were filled. Flaps were elevated bilaterally, the premolars hemi-sectioned, and the distal roots removed. Recipient sites were prepared in the distal alveolus, and implants were placed. At the test sites, DBBM particles were placed in the residual marginal defects concomitantly with the placement of a collagen membrane. No treatment augmentation was performed at the control sites. A non-submerged healing was allowed. Impressions were obtained at baseline and at the time of sacrifice performed 4 months after surgery. The cast models obtained were analyzed using an optical system to evaluate dimensional variations. Block sections of the implant sites were obtained for histological processing and soft tissue assessments. Results After 4 months of healing, no differences in soft tissue dimensions were found between the test and control sites based on the histological assessments. The location of the soft tissue at the buccal aspect was, however, more coronal at the test compared with the control sites (1.8 +/- 0.8 and 0.9 +/- 0.8 mm, respectively). At the three-dimensional evaluation, the margin of the soft tissues at the buccal aspect appeared to be located more apically and lingually. The vertical dislocation was 1 +/- 0.6 and 2.7 +/- 0.5 mm at the test and control sites, respectively. The area of the buccal shrinkage of the alveolar crest was significantly smaller at the test sites (5.9 +/- 2.4 mm2) compared with the control sites (11.5 +/- 1.7 mm2). Conclusion The use of DBBM particles concomitantly with the application of a collagen membrane used at implants placed into sockets immediately after tooth extraction contributed to the preservation of the alveolar process.

Hard tissue formation adjacent to implants of various size and configuration immediately placed into extraction sockets: an experimental study in dogs

ObjectivesTo evaluate the influence of implant size and configuration on osseointegration in implants immediately placed into extraction sockets.Material and methodsImplants were installed immediately into extraction sockets in the mandibles of six Labrador dogs. In the control sites, cylindrical transmucosal implants (3.3 mm diameter) were installed, while in the test sites, larger and conical (root formed, 5 mm diameter) implants were installed. After 4 months of healing, the resorptive patterns of the alveolar crest were evaluated histomorphometrically.ResultsWith one exception, all implants were integrated in mineralized bone, mainly composed of mature lamellar bone. The alveolar crest underwent resorption at the control as well as at the test implants. This resorption was more pronounced at the buccal aspects and significantly greater at the test (2.7 +/- 0.4 mm) than at the control implants (1.5 +/- 0.6 mm). However, the control implants were associated with residual defects that were deeper at the lingual than at the buccal aspects, while these defects were virtually absent at test implants.ConclusionsThe installment of root formed wide implants immediately into extraction sockets will not prevent the resorption of the alveolar crest. In contrast, this resorption is more marked both at the buccal and lingual aspects of root formed wide than at standard cylindrical implants.To cite this article:Caneva M, Salata LA, de Souza SS, Bressan E, Botticelli D, Lang NP. Hard tissue formation adjacent to implants of various size and configuration immediately placed into extraction sockets: an experimental study in dogs.Clin. Oral Impl. Res. 21, 2010; 885-895.doi: 10.1111/j.1600-0501.2010.01931.x.

Deproteinized bovine bone mineral in marginal defects at implants installed immediately into extraction sockets: an experimental study in dogs

Aim: To evaluate the influence of deproteinized bovine bone mineral (DBBM) particles concomitant with the placement of a collagen membrane on alveolar ridge preservation and on osseointegration of implants placed into alveolar sockets immediately after tooth extraction. Material and methods: The pulp tissue of the mesial roots of 3P3 was removed in six Labrador dogs and the root canals were filled. Flaps were elevated in the right side of the mandible, and the buccal and lingual alveolar bony plates were exposed. The third premolar was hemi-sectioned and the distal root was removed. A recipient site was prepared and an implant was placed lingually. After implant installation, defects of about 0.6mm wide and 3.1mm depth resulted at the buccal aspects of the implant, both at the test and at the control sites. The same surgical procedures and measurements were performed on the left side of the mandible. However, DBBM particles with a size of 0.25-1mm were placed into the remaining defect concomitant with the placement of a collagen membrane. Results: All implants were integrated into mature bone. No residual DBBM particles were detected at the test sites after 4 months of healing. Both the test and the control sites showed buccal alveolar bone resorption, 1.8 +/- 1.1 and 2.1 +/- 1mm, respectively. The most coronal bone-to-implant contact at the buccal aspect was 2 +/- 1.1 an 2.8 +/- 1.3mm, at the test and the control sites, respectively. This difference in the distance was statistically significant. Conclusion: The application of DBBM concomitant with a collagen membrane to fill the marginal defects around implants placed into the alveolus immediately after tooth extraction contributed to improved bone regeneration in the defects. However, with regard to buccal bony crest preservation, a limited contribution of DBBM particles was achieved.

Influence of implants with different sizes and configurations installed immediately into extraction sockets on peri-implant hard and soft tissues: an experimental study in dogs

Aim: To study the influence on the healing of soft and hard peri-implant tissues when implants of different sizes and configurations were installed into sockets immediately after tooth extraction.Material and methods: Transmucosal cylindrical implants, 3.3 mm in diameter in the control sites, and conical 5 mm in diameter in the test sites, were installed into the distal socket of the fourth mandibular premolars in dogs immediately after tooth extraction. After 4 months, the hard and soft tissue healing was evaluated histologically. Results: All implants were integrated in mineralized mature bone. Both at the test and control sites, the alveolar crest underwent resorption. The buccal bony surface at the implant test sites (conical; 3.8 mm) was more resorbed compared with the control sites (cylindrical; 1.6 mm). The soft tissue dimensions were similar in both groups. However, in relation to the implant shoulder, the peri-implant mucosa was located more apically at the test compared with the control sites.Conclusion: The present study confirmed that the distance between the implant surface and the outer contour of the buccal alveolar bony crest influenced the degree of resorption of the buccal bone plate. Consequently, in relation to the implant shoulder, the peri-implant mucosa will be established at a more apical level, if the distance between the implant surface and the outer contour of the alveolar crest is small.

Role of teeth adjacent to implants installed immediately into extraction sockets: an experimental study in the dog

Aim: To evaluate the influence of the presence of both adjacent teeth on the level of alveolar bony crest at sites where implants were installed into the socket immediately after tooth extraction.Material and methods: Six Labrador dogs were used. Extractions of all teeth from the second premolar to the first molar were performed in the right side of the mandible, after full-thickness flap elevation. In the left side of the mandible, an endodontic treatment of the mesial root of the third and fourth premolars was performed. Full-thickness flaps were elevated, the teeth hemisected, and the distal roots removed. Immediately after, implants were bilaterally installed with the margin flush to the buccal bony crest. The implants were placed in the center of the alveolus at the third premolars and toward the lingual bony plate of the alveolus at the fourth premolars. After 3 months of healing, the animals were euthanized.Results: All implants were integrated in mature bone. More bone resorption was observed at the test compared to the control sites. At the buccal aspect, a resorption of 2.8 +/- 0.5 and 1.6 +/- 0.4 mm at the third premolars and of 2.4 +/- 0.6 and 0.8 +/- 0.7 mm at the fourth premolars were found, at the test and control sites, respectively. At the lingual aspect, the bony crest was apically located in relation to the implant shoulder 1.5 +/- 0.3 and 0.5 +/- 0.5 mm at the third premolars and 1.6 +/- 0.6 and 0.3 +/- 1.1 mm at the fourth premolars, at the test and control sites, respectively. A lower buccal bone resorption was found at the control implants placed lingually.Conclusion: Multiple extractions of teeth adjacent to a socket into which implants were installed immediately after, tooth extraction induced more alveolar bone recession compared to sites where the adjacent teeth were preserved. Moreover, an implant placed more lingually yielded less recession of the buccal aspect of the implant.

Influence of implant positioning in extraction sockets on osseointegration: Histomorphometric analyses in dogs

Aim: To evaluate the influence of implant positioning into extraction sockets on osseointegration. Material and methods: Implants were installed immediately into extraction sockets in the mandibles of six Labrador dogs. In the control sites, the implants were positioned in the center of the alveolus, while in the test sites, the implants were positioned 0.8 mm deeper and more lingually. After 4 months of healing, the resorptive patterns of the alveolar crest were evaluated histomorphometrically. Results: All implants were integrated in mineralized bone, mainly composed of mature lamellar bone. The alveolar crest underwent resorption at the control as well as at the test sites. After 4 months of healing, at the buccal aspects of the control and test sites, the location of the implant rough/smooth limit to the alveolar crest was 2±0.9 mm and 0.6±0.9 mm, respectively (P<0.05). At the lingual aspect, the bony crest was located 0.4 mm apically and 0.2 mm coronally to the implant rough/smooth limit at the control and test sites, respectively (NS). Conclusions: From a clinical point of view, implants installed into extraction sockets should be positioned approximately 1 mm deeper than the level of the buccal alveolar crest and in a lingual position in relation to the center of the alveolus in order to reduce or eliminate the exposure above the alveolar crest of the endosseous (rough) portion of the implant. © 2009 John Wiley & Sons A/S.

Temporal localization of osteocalcin protein during healing of tooth extraction sockets in rats.

The aim of this study was to evaluate the expression of osteocalcin protein during the alveolar bone healing process in rats. Twenty four rats were used in this study and, after anesthetic induction, they had their right upper incisors extracted. At 7, 14, 21 and 28 days after the tooth extraction, the animals were injected 4% formaldehyde. The histological tissue pieces were colored in hematoxilin and eosin and the immunohistochemistry reaction for osteocalcin was performed. At seven days lesser neoformed trabeculae bone and a small quantity of osteocalcin labeling were observed. At 14 and 21 days a larger quantity of neoformed trabeculae bone and higher osteocalcin values were detected. At 28 days the largest quantity of neoformed trabeculae bone and a decrease on the amount of osteocalcin immunolabelling were noticed. According to our results and considering the limits of the present study it is possible to conclude that a greater osteocalcin expression is observed at 14 and 21 days postoperatively, characterizing the periods when intense mineralization of the bone tissue occurs during the alveolar bone healing process.

Connective tissue grafts in conjunction with implants installed immediately into extraction sockets. An experimental study in dogs

Aim: To evaluate the influence of a sub-epithelial connective tissue graft placed at the buccal aspect of implants installed immediately after tooth extraction on the dimensional changes of hard and soft tissues. Materials and Methods: In six Labrador dogs a bilateral partial- thickness dissection was made buccal to the second mandibular premolar. At the lingual aspect, full-thickness flaps were elevated. The teeth were extracted and implants installed immediately into the distal socket. A connective tissue graft was obtained from the palate and applied to the buccal aspect of the test sites, whereas contra-laterally, no graft was applied. The flaps were sutured to allow a non-submerged installation. After 4 months of healing, the animals were sacrificed, ground sections were obtained and histomorphometric analyses were performed. Results: After 4 months of healing, all implants were integrated (n = 6). Both at the test and at the control sites bone resorption occurred: 1.6 mm and 2.1 mm, respectively. The difference was not statistically significant. The coronal aspect of the peri-implant soft tissue was wider and located more coronally at the test compared with the control sites. The differences were statistically significant. Conclusions: The application of a connective tissue graft placed at the buccal aspect of the bony wall at implants installed immediately after tooth extraction yielded a minimal preservation of the hard tissues. The peri-implant mucosa, however, was significantly thicker and more coronally positioned at the test compared with the control sites. © 2012 John Wiley & Sons A/S.

Influence of presence or absence of teeth adjacent to implants installed immediately into extraction sockets on peri-implant hard tissue levels: An experimental study in the dog

Aim: To evaluate the influence of the presence or absence of adjacent teeth on the level of the mesial and distal alveolar bony crest following healing at sites where implants were installed immediately into extraction sockets. Material and methods: Six Labrador dogs were used. In the right side of the mandible, full-thickness flaps were elevated, and the second, third, and fourth premolars and first molars were extracted. In the left side of the mandible, endodontic treatments of the mesial roots of the third and fourth premolars as well as of the first molars were performed. Full-thickness flaps were elevated, the teeth were hemi-sected, and the distal roots were removed. The second premolars were extracted as well. Subsequently, implants were bilaterally installed with the implant shoulder flush with the buccal bony crest. Implants were placed in the center of the alveoli, but at the fourth premolars, they were placed toward the lingual bony plate of the alveoli. After 3 months of healing, the animals were euthanized and histological sections of the sites prepared. Results: Larger bony crest resorption was observed at the test compared with the control sites, both at the bucco-lingual and mesio-distal aspects. The differences between test and controls for the coronal level of osseointegration were smaller than those for resorption. When data from all mesial and distal sites facing an adjacent tooth were collapsed and compared with those opposing an edentulous zone, lower bony crest resorption and deeper residual marginal defects were found at the sites with neighboring teeth. Conclusion: The extraction of teeth adjacent to a socket into which implants were installed immediately after tooth extraction caused more alveolar bone resorption both for the bucco-lingual and at the mesio-distal aspects compared with sites adjacent to a maintained tooth. © 2012 John Wiley & Sons A/S.