Correction to: Influence of surface treatment on osseointegration of dental implants: histological, histomorphometric and radiological analysis in vivo.

Dear Professor Dr. Matthias Hannig. Editor-in-Chief Clinical Oral Investigations. Following the publication of our paper by Calvo Guirado et al, 2015 [1] in Clinical Oral Investigations, it came to light that a certain part of the text at the materials and methods and results sections were similar.

The influence of drill length and irrigation system on heat production during osteotomy preparation for dental implants: an ex vivo study.

OBJECTIVE: This study aimed to measure the influence of drill length and irrigation system on heat production during osteotomy preparation for dental implants using bovine bone rib as experimental model. MATERIALS AND METHODS: Three groups were created: Group 1: drilling with three consecutive burs with double irrigation (internal and external) for a 4.0 mm conical implant; and Group 2 and Group 3: drilling with three consecutive burs with external irrigation for a 4.1 mm cylindrical implant and for a 4.3 mm conical implant, respectively. Four lengths were tested: 10, 12, 14 and 16 mm; in site prepared on bovine ribs using a surgical unit linked to a testing device, to standardize and simulate implant drilling procedures. Bone temperature variations were recorded using three thermocouples in different positions as of the crestal bone: 2 mm, position (p1); 7 mm, position 2 (p2); and 12 mm, position 3 (p3). RESULTS: The highest temperature changes were invariably recorded during the process of withdrawal. Significantly lower temperature changes (P < 0.02) could be recorded at maximum drilling depths during the shearing process regardless of drilling depth or irrigation method. Double irrigation was associated with significantly lower temperatures compared with external irrigation by the use of implant drills (P < 0.01). CONCLUSIONS: Within the limitations of this ex vivo study was possible concluded that the use a double irrigation system in multiple conventional drill for osteotomy can decrease the heat generation when increase the drill length.

Peri-implant bone loss clinical and radiographic evaluation around rough neck and microthread implants: a 5-year study.

OBJECTIVE: To evaluate marginal bone loss over 5 years around microthreaded implants placed in the maxillary anterior/esthetic zone and immediate restored with non-occlusal loading. MATERIALS AND METHODS: Seventy-one implants (with microthreads up to the platform-rough surface body and neck, internal connection and platform switching) were placed in healed bone in the maxillary arches of 30 men and 23 women (mean age 37.85 ± 7.09 years, range 27-60). All subjects had at least 3 mm of soft tissue to allow the establishment of adequate biologic width and to reduce bone resorption. Each patient received a provisional restoration immediately after implant placement with slight occlusal contact. Mesial and distal bone height was evaluated using digital radiography on the day following implant placement (baseline) and after 1, 2, 3, 4 and 5 years. Primary stability was measured with resonance frequency analysis. RESULTS: No implants failed, resulting in a cumulative survival rate of 100% after 3 years. Marginal bone loss from implant collar to bone crest measured at baseline (peri-implant bone defect at the fresh extraction socket) and after 5 years was 0.90 mm ± 0.26 mm. Mesial and distal site crestal bone loss ranged from 3.42 ± 1.2 mm at baseline to 3.51 ± 1.5 mm after 5 years and from 3.38 ± 0.9 mm at baseline to 3.49 ± 0.9 mm after 5 years, respectively (P = 0.086). CONCLUSIONS: The results of this study showed limited implant crestal bone loss 0.90 mm ± 0.26 mm and 100% of implant survival rate at 5-year follow-up of immediate restored implants with rough surface neck and microthreads.

Role of mechanical compression on bone regeneration around a particulate bone graft material: an experimental study in rabbit calvaria.

PURPOSE: This experimental study was designed to analyze the effect of different compressive forces on the bone regeneration around a particulate bone graft material. MATERIAL AND METHODS: Eighty 6-mm-diameter defects were created in the calvaria of 20 New Zealand rabbits (4 defects per rabbit calvaria). All the defects were filled with particles of synthetic bone. Two standardized compressive forces were then applied, 4.1 g to half the defects (Test A) and 8.2 g to the other half (Test B), all for 1 min. The graft sites were allowed to heal for 6 weeks, after which the rabbits were euthanized. The calvarium vault of each animal was extracted, radiographed, and prepared for histomorphometric analysis. The percentage of defect fill, bone density, new bone formation, and residual bone graft material were recorded, and the results were subjected to statistical analysis. RESULTS: Histological evaluation found that defect closure among the Test A (lower compression) group ranged from 38.34 (95% lower CI) to 55.8 (95% upper CI) (mean 47 ± 8.5%), while among the Test B group (higher compression), it ranged from 81.26 (95% lower CI) to 95.32 (mean 88 ± 7.3%). Significantly more closure was achieved for the Test B group (P < 0.05). Histomorphometric comparison of the two groups found significantly more new bone formation, higher bone density, and a higher percentage of defect fill in the defects subjected to the higher compression level (P < 0.05). CONCLUSIONS: Increasing the compressive force applied to bone graft particulate used to fill small defects created in rabbit calvaria appears to be beneficial.

Influence of hydroxyapatite granule size, porosity, and crystallinity on tissue reaction in vivo. Part B: a comparative study with biphasic synthetic biomaterials.

OBJECTIVE: The aim of this study was to compare the influence of the physical-chemical properties of synthetic hydroxyapatite (HA) and biphasic commercial materials on the biological behavior of study materials through material characterization and SEM analysis before and after application in rabbit tibias. MATERIALS AND METHODS: Two defects were performed in each tibiae for a total of 180 defects: Group I HA granules (2000-4000 µm), Group II HA granules (1000-2000 µm), Group III HA granules (600-1000 µm), Group IV Ossceram® nano (Bredent medical GmbH & Co. KG, Senden, Germany), Group V 4Bone® granules (MIS Implants Technologies Ltd, Shlomi, Israel), and Group VI: empty defect acted as control. Comparison was performed by mean of material characterization, SEM, and EDX. RESULTS: 4Bone: Pores between 300 µm and 100 µm with intra- and interparticle spaces. Ossceram show also interparticle and intraparticle pores, between 100 µm and 26 µm, but the proportion of interparticles in the 4Bone is clearly minor than in the Ossceram. Related with pure HA, Group III has the greatest porosity (69.3%). For Group I, the intraparticle pores (0.71 µm) are about 8 times larger than those of the other two samples. The analysis of the images of in vivo SEM shown as biphasic groups has presented a more gradual resorption of the material. CONCLUSION: HA-based biomaterials, both pure and biphasic, are an effective means for bone regeneration processes; of these, materials with higher initial and secondary porosimetry allow greater cell colonization and therefore more effective substitution by new bone. The two-phase materials have a higher ion release to the environment in the early stages and thus allow greater colonization by collagen fibers that can be matured into new bone.

Effects on the osseointegration of titanium implants incorporating calcium-magnesium: a resonance frequency and histomorphometric analysis in rabbit tibia.

OBJECTIVE: This study assessed the bone formation around titanium surface incorporating the calcium-magnesium (CaMg) deposited by blasted in rabbit tibia bone to determine whether this surface would further enhance bone healing compared with commercially available implant surface. MATERIAL AND METHODS: The deposition of CaMg on the titanium SLA surface were obtained by blasting formed the experimental group (EX group), while implants with traditional SLA surface were used as control group (CO group), in this study. Fifty cylindrical threaded implants with a length of 8 mm were used (P = 25 per group). Five implants of each group were used to surface characterization by scanning electron microscopy, energy dispersive spectrometry, and optical profilometry. Ten New Zealand white rabbits received 40 implants (n = 20 per group). Resonance frequency analysis was performed three times (0, 4, and 6 weeks). Histomorphometric analysis was performed 4 and 6 weeks after implantation. Statistical significance was set at P < 0.05. RESULTS: Blasted CaMg deposition on SLA implant surface displayed almost identical surface morphologies and R(a) values at the micron scale. In comparing the implant stability quotient at the three time points, highly significant statistic differences were found (P < 0.001). Histomorphological analysis showed higher degrees of bone organization in the samples of test implant surfaces at both implantation times. CONCLUSION: Within the limitations of this study, the results indicate that the deposition of CaMg on the SLA titanium surface may be effective in enhancing the osseointegration of moderately rough grit-blasted implants by increasing the degree of bone-implant contact.

Retracted: A new cervical implant design compared with standard design in order to increase peri-implant hard and soft tissue behavior: histomorphometric and histological study in dogs.

OBJECTIVE: The aim of this study was to evaluate a new design of the cervical portion of dental implant with the objective to increase the volume of peri-implant tissues in the crestal area. MATERIALS AND METHODS: Forty-eight tapered dental titanium implants with internal conical connection were implanted in healed alveolar sites of six dogs. Twenty-four conventional implants design (C1 implant) formed the control group, and 24 new implant design (V3 implant) formed the test group. The groups were randomized. Histological, histomorphometric, and implant stability quotient were performed. After 12 weeks of healing period, histomorphometric analyses of the specimens were carried out to measure the crestal bone level values and the tissue thickness in the cervical implant portion. The data were compared using statistical tests (α = 5%). RESULTS: The mean of the measurements in the buccal and lingual aspects measured of crestal bone level was 0.31 ± 0.24 mm and 0.30 ± 0.19 mm in the control group, respectively, and 0.71 ± 0.28 and 0.42 ± 0.30 mm in the test group, respectively, whereas the mean of the tissue thickness was 1.63 ± 0.33 mm and 2.04 ± 0.23 mm in the control group, respectively, and 2.11 ± 0.35 mm and 2.51 ± 0.41 mm in the test group. CONCLUSIONS: Within the limitations of this study, our findings suggest that more thickness of peri-implant hard and soft tissues may be expected in this new implant design. However, the control group with traditional implant design was found to have more height values of the crestal bone compared with new V3 implants.

Biological effects of compressive forces exerted on particulate bone grafts during socket preservation: animal study.

OBJECTIVES: To compare different compressive forces exerted on a particulate graft material during socket preservation and their effects on bone regeneration. MATERIAL AND METHODS: Six male dogs were used. The second, third, and fourth premolars, and the first molar were extracted bilaterally at the lower jaws. A particulate synthetic biphasic grafting material (60% HA and 40% ß-tricalcium phosphate) was used. Three different standardized compressive forces were applied randomly during the socket preservation. The sample was divided into four experimental groups Test A (10 g), Test B (50 g), Test C (200 g), and Control (empty sockets). Collagen membranes were placed, and primary closure was obtained. Two months after the surgery the animals were sacrificed, and histomorphometric analysis of non-decalcified samples was performed at the coronal, middle, and apical thirds. RESULTS: Grafted sockets resulted in higher bony contour (3 ± 0.43 mm2 ; P < 0.05). The particles penetrated up to the apical third in the group C but not in the other test groups and controls (P < 0.05). The percentage of new bone were higher at the coronal and apical thirds for Controls and group C compared to A and B groups (P < 0.05). The residual graft was higher for group C (53 ± 1.4%), followed by group B (45 ± 3.1%) and group A (35 ± 1.9%; P < 0.05). The percentages of connective tissue were higher at the middle third without differences between groups (P > 0.05). CONCLUSIONS: Within the limitations of this experimental animal study, it might be concluded that grafted sockets compressed with 200 g force will have higher bony contours; higher compressive forces facilitate the penetration of the particulate graft material into the apical area of the socket and results in more bone formation at the coronal, middle, and apical thirds.

Topical applications of vitamin D on implant surface for bone-to-implant contact enhance: a pilot study in dogs part II.

OBJECTIVE: The aim of this study was to evaluate the effect of topical application of vitamin D over implant surface, placed immediately to the extraction, throughout histological and histomorphometric analysis of peri-implant tissue. MATERIAL AND METHODS: Six American foxhound dogs were used in the study. Mandibular premolar distal roots were extracted. Twenty-four immediate conical C1 implants (MIS, Barlev, Israel) were randomly assigned to the distal site on each site of the mandible in three groups: (Group CI) 12 titanium implants alone; (Test Group DI) 12 titanium implants supplemented with vitamin D. Prior to implanting, test implants (DI) were submerged in vitamin D 10% solution. No treatment was applied at control implants (CI). After 12 weeks, animals were sacrificed. Block sections were obtained and processed for mineralized ground sectioning. Bone-to-implant contact (Total BIC and BIC%), new bone formation (NBF), interthread bone (ITB), and histological linear measurements (HLM) were analyzed. RESULTS: At 12 weeks, all implants were clinically stable and histologically osseointegrated. BIC evaluation showed Total BIC mean and SD values for DI (48.96 ± 2.14), CI (44.56 ± 1.75) (P < 0.05), BIC% DI (43.59 ± 0.98), and CI (42.67 ± 9.26) (P > 0.05). For interthread bone formation, values were as follows: DI (15.21 ± 3.87), CI (14.79 ± 1.45) (P > 0.05), no statistically differences. Regarding peri-implant new bone formation, no statistically differences could be found between the two groups DI (31.87 ± 1.23), CI (27.18 ± 2.38) (P > 0.05). For linear measurements, test group (DI) showed statistically significant less buccal crestal bone loss (CBL) DI (0.37 ± 0.12)*, CI (1.26 ± 0.8) (P < 0.05), and vitamin D implants showed less lingual junctional epithelium DI (1.58 ± 0.43)*, CI (2.18 ± 0.48) (P < 0.05). No differences were observed in the buccal mucosa. CONCLUSION: With the limitation of animal studies, topical application of vitamin D on dental implants could reduce crestal bone loss and increase 10% more bone-to-implant contact at 12-week follow-up period.

Evaluation of extrashort 4-mm implants in mandibular edentulous patients with reduced bone height in comparison with standard implants: a 12-month results.

OBJECTIVE: The aim of this research was to evaluate the primary stability, the marginal bone loss, the survival, and the success criteria, of 4-mm-length implants compared with implants of conventional length supporting fixed prostheses. MATERIALS AND METHODS: Ten patients were selected for treatment of their atrophic edentulous jaws. Each patient received the following treatment: six dental implants were inserted, two anterior implants of conventional length (10-mm) in the interforaminal area and four posterior short implants of 4-mm length (Standard Plus, Roxolid, SLActive, Institut Straumann AG). The implants supported screw-retained fixed complete dentures. Examinations were conducted at day 0, three, six, and twelve months after surgery for the evaluation of the implant primary stability, secondary stability, crestal bone loss and survival by clinical evaluations, insertion torque values, resonance frequency analysis (RFA), and periapical radiography, respectively. RESULTS: Sixty implants were inserted in ten patients. Mean insertion torque was slightly lower for 4-mm implants than 10-mm implants (38.1 Ncm vs. 42.2 Ncm) but without statistically significant difference. Implant stability was similar for extrashort and conventional implants. Marginal bone loss was similar for both groups for all the time periods. One short implant was lost before loading. The survival rates twelve months after implant placement were of 97.5% and 100% for short and conventional implants, respectively. Similarly, implant stability as measured by RFA was nonsignificantly lower for the 4-mm implants compared to the 10-mm implants. The marginal bone loss was lower for short implants three, six, and twelve months after the surgery without statistical significant difference. CONCLUSIONS: Within the limitations of this study, we conclude that short dental implants (8 mm or less in length) supporting single crowns or fixed bridges are a feasible treatment option with radiographic and clinical success rates similar to longer implants for patients with compromised ridges. Long-term data with larger number of implants and subjects are needed to confirm these preliminary results.

Bone response to collagenized xenografts of porcine origin (mp3(®) ) and a bovine bone mineral grafting (4BONE(™) XBM) grafts in tibia defects: experimental study in rabbits.

OBJECTIVES: This study aimed to carry out the evaluation of bone response of new bone formation to two different xenografts (bovine and porcine) biomaterials inserted in rabbit tibiae. MATERIALS AND METHODS: The study used a total of 20 male New Zealand albino rabbits. They received a total of 40 grafts in the proximal metaphyseal areas of both tibiae. Two biomaterials were evaluated: 20 porcine xenografts, as a bone granulate (OsteoBiol(®) MP3(®) ; Tecnoss srl, Giaveno, Italy), were placed in the proximal metaphyseal area of the right tibia, 20 anorganic bovine bone mineral grafting (4BONE(™) XBM, MIS Implants Inc., BARLEV, Israel) were placed in the left tibia. Following graft insertion, the animals were sacrificed in two groups of 10 animals, after 1 and 4 months, respectively. For each group, biomaterials were analyzed: newly formed bone, residual graft materials and the connective tissue. Histomorphometric, EDX analysis and element mapping were performed at 1 and 4 months after graft insertion. RESULTS: At 4 months after treatment, the bone defects displayed radiological images that showed complete repair of osseous defects. Histomorphometric evaluation showed that for the porcine xenograft, the study averages for newly formed bone represented 84.23 ± 2.9%, while bovine matrix was 79.34 ± 2.1%. For residual graft material, the porcine biomaterial had 11.23 ± 1.7% and the bovine graft 31.56 ± 2.3%. Finally, the connective tissue for MP3 was 10.33 ± 1.8%, while for the 4BONE(™) XBM we obtained 14.34 ± 2.9%. Element analysis revealed higher percentages of Ca (54 ± 9%) and P (35 ± 6%) in the group B than group A and control group (P < 0.05). CONCLUSIONS: Defects of a critical size in a rabbit tibia model can be sealed using a bovine porous biphasic calcium phosphate and MP3 material; this supports new bone formation, creates a bridge between borders, and facilitates bone ingrowth in both biomaterials. Furthermore, this study observed partial dissolution of the mineral phase of four bone graft and complete resorption of porcine MP3 biomaterial and its incorporation into the surrounding bone. Depending on clinical needs, each biomaterial could be useful in daily clinical practice.

Bone neoformation of a novel porous resorbable Si-Ca-P-based ceramic with osteoconductive properties: physical and mechanical characterization, histological and histomorphometric study.

OBJECTIVE: The aims of the present work were to study a new porous Nurse's A ceramic (Si-Ca-P-based material) bone substitute and examine its mechanical properties in vitro and the biocompatibility, osteoconductivity and resorption process in vivo. MATERIALS AND METHOD: Porous ceramic scaffolds were prepared by solid-state reaction and implanted in critical-sized defect created in 15 NZ rabbits. Strength values were determined by the diametrical compression of disk test. Weibull analyses were performed following the European Standard for technical ceramics EN-843-5: 1996, considering 90% of confidence intervals. Results were correlated with scanning microscope observations of fracture surfaces. Implanted scaffolds were characterized by histological and histomorphometric point of view. RESULTS: The parameters of the Weibull distribution of strength, determined by diametrical compression of disks, were modulus m = 13, and characteristic strength σ0  = 0.60 MPa (90% confidence limit: m = 7.2-17.6, σ0  = 0.570-0.578). Porous calcium silicophosphate scaffolds showed significantly more bone formation in the pores and in the periphery of the implant than the control group. Histomorphometric analysis revealed that the ceramic scaffold (62.23 ± 0.34*) produced higher values of bone-to-implant contact (BIC) percentages (higher quality, closer contact); moreover, defect closure was significative in relation with control group. CONCLUSIONS: The porous calcium silicophosphate ceramic is biocompatible, partially resorbable and osteoinductive material. This rabbit study provides radiological and histological evidences confirming the suitablity of this new material for bone tissue regeneration on critical defects.

Influence of hydroxyapatite granule size, porosity, and crystallinity on tissue reaction in vivo. Part A: synthesis, characterization of the materials, and SEM analysis.

OBJECTIVE: The aim of this study was the synthesis and analysis of the tissue reaction to three different Hydroxyapatite (HA)-based bone substitute materials differing only in granule size, porosity, and crystallinity through an animal experimental model at 60 days. MATERIALS AND METHODS: Three different HA-based biomaterials were synthesized and characterized by X-ray diffraction, SEM, and EDS analysis, the resultant product was ground in three particle sizes: Group I (2000-4000 µm), Group II (1000-2000 µm), and Group III (600-1000 µm). Critical size defects were created in both tibias of 15 rabbits. Four defects per rabbit for a total of 60 defects were grafted with the synthesized materials as follows: Group I (15 defects), Group II (15 defects), Group III (15 defects), and empty (15 defects control). After animals sacrifice at 60 days samples were obtained and processed for SEM and EDS evaluation of Ca/P ratios, elemental mapping was performed to determine the chemical degradation process and changes to medullary composition in all the four study groups. RESULTS: The tendency for the density was to increase with the increasing annealing temperature; in this way it was possible to observe that the sample that shows highest crystallinity and crystal size corresponding to that of group I. The SEM morphological examination showed that group III implant showed numerous resorption regions, group II implant presented an average resorption rate of all the implants. The group I displayed smoother surface features, in comparison with the other two implants. CONCLUSION: The data from this study show that changing the size, porosity, and crystallinity of one HA-based bone substitute material can influence the integration of the biomaterials within the implantation site and the new bone formation.

Histological and histomorphometric analyses of narrow implants, crestal and subcrestally placed in severe alveolar atrophy: a study in foxhound dogs.

BACKGROUND: Narrow-diameter implants provide an alternative to the horizontal augmentation techniques situations severe bone atrophy. Lack of bone width and interdental space has been regarded as an encumbrance in the case selection for prosthetic rehabilitation using dental implants. OBJECTIVE: The aim of the study was to evaluate bone-to-implant contact and marginal bone loss of two different narrow implants in resorbed ridges at different crestal positions. MATERIAL AND METHODS: 48 Bredent Narrow(®) implants (24 MiniSky(®) and NarowSky(®) ) were placed at crestal and subcrestal levels in healing bone of atrophic alveolar ridge of 6 American foxhounds. Histological and histomorphometric analyses of osseointegration were carried out at 4 and 8 weeks. RESULTS: Modeling in the marginal defect region was accompanied by marked decreases in the dimensions of both the buccal and the more lingual bone walls. Relative to BIC, significant differences were found in favor of subcrestal group, for both Narrow Sky and MiniSky. Linear measurements showed to be slightly high in the crestal group. With significant differences for PM-IS (peri-implant mucosa to implant shoulder) and IS-BC (implant shoulder to buccal bone crest). CONCLUSIONS: Within the limitations of animal study, it can be stated that the NarrowSky(test group) crestal and subcrestal implants showed less crestal bone resorption, higher ISQ values and most BIC at 4 and 8 weeks of evaluation compared with MiniSky implants (control group). The design of the implants plays an important role in peri-implant mucosa and crestal bone maintenance at 8-week follow-up period.

Retracted: In vivo behavior of hydroxyapatite/ß­TCP /collagen scaffold in animal model. Histological, histomorphometrical, radiological, and SEM analysis at 15, 30, and 60 days

Retraction: Maté Sánchez de Val JE , Calvo Guirado JL , Ramírez Fernández MP , Delgado Ruiz RA , Mazón P, De Aza PN . In vivo behavior of hydroxyapatite/ß­TCP /collagen scaffold in animal model. Histological, histomorphometrical, radiological, and SEM analysis at 15, 30, and 60 days. Clin Oral Impl Res . The above article, published online on August 7, 2015, in Wiley Online Library (wileyonlinelibrary.com) has been retracted by agreement between the journal editor­in­chief, L Heitz­Mayfield, and John Wiley & Sons Ltd. The retraction has been agreed due to image discrepancies resulting in unreliable data. It has not been possible to prove the validity of the images. Images in Figure 4 have been used in other publications representing different time points and materials. Images within Figure 4 have been manipulated to represent different time points and materials. Reference Maté Sánchez de Val JE , Calvo Guirado JL , Ramírez Fernández MP , Delgado Ruiz RA , Mazón P, De Aza PN . In vivo behavior of hydroxyapatite/ß­TCP /collagen scaffold in animal model. Histological, histomorphometrical, radiological, and SEM analysis at 15, 30, and 60 days. Clin Oral Impl Res . https://doi.org/10.1111/clr.12656

Influence of collar design on peri-implant tissue healing around immediate implants: A pilot study in Foxhound dogs.

PURPOSE: The study aims to assess the soft tissue level (STL) and crestal bone level (CBL), of titanium dental implants with different mixed collar abutments configurations. MATERIALS AND METHODS: This study included 48 implants with the same dimensions. They were divided into two groups of 24 implants each one: implants with a polished collar of 2 mm plus a roughened area of 0.8 mm (CONTROL) and implants with a polished collar of 0.8 mm plus a micro-threated and roughened area of 2 mm (TEST). The implants were inserted randomly in the post-extraction sockets of P2, P3, P4, and M1 bilaterally in the lower jaw of six foxhound dogs. STL and CBL were evaluated after 8 and 12 weeks by histology and histometry. RESULTS: All implants were clinically and histologically osseointegrated. Healing patterns examined microscopically at 8 and 12 weeks for both groups yielded similar qualitative findings for the STL evaluation, without significant differences between groups (P > 0.05). CBL was significantly higher in the buccal side in comparison with the lingual side for both groups (P < 0.05); the comparison between groups at 8 weeks showed IS-B (distance from the implant shoulder to the top of the bony crest) and IS-C (distance from the implant shoulder to the first bone-to-implant contact) values significantly higher for control group in comparison with test (P < 0.05). At 12 weeks, CBL showed increased values for both groups that were higher in controls group in comparison with test (P < 0.05). CONCLUSIONS: Bony crest resorption could not be avoided both at test and control sites. However, the neck conformation at the test sites reduced the buccal bone resorption. Soft tissue dimensions were similar both at the test and control sites.

Biological width formation to immediate implants placed at different level in relation to the crestal bone: an experimental study in dogs.

PURPOSE/AIM: Evaluate differences in bone remodeling, soft tissue reactions and biological width formation around immediate implants placed at different level in relation to the crestal bone in beagle dogs. MATERIAL AND METHODS: The mandibular second, third and fourth premolars of six beagle dogs were extracted, and three implants were placed in the right side of each dog. Healing abutments were adjusted (n = 18). After 4 weeks, the procedure was repeated on the left side of the mandible (n = 18). Randomly, three implants were placed at crestal level (control group), and three implants were placed 2 mm subcrestally (test group) in relation to the crestal bone in each animal. The dogs were sacrificed after 8 weeks from the first surgical procedure, and biopsies were obtained. Samples were processed for ground sectioning. Histometric analysis was carried out to compare buccal and lingual bone resorption, soft tissue behavior and biological width formation in both groups. RESULTS: Crestal bone resorption was higher in the test group when considering the difference of 2 mms (IS-B = 2.05 ± 0.36 mm, control; 1.75 (+2) ± 0.38 mm, test). However, the dimensions of the biological width were similar for both groups (PM-C = 3.34 ± 0.53 mm, control; 3.13 ± 0.55 mm, test). CONCLUSIONS: The alterations that occurred in the peri-implant soft tissues may be related to the hard tissue remodeling, showing similar quantitative findings in the biological width formation in both groups. Even though the subcrestal placement might reduce the distance from the implant shoulder to the first bone-to-implant contact and reestablish the biological width dimension in a most coronal position, it might not have any effect on minimizing the marginal bone loss.

Implants failures related to endodontic treatment. An observational retrospective study.

OBJECTIVE: The aim of the study was to analyze potential etiological risk factors that constitute a complex problem in the clinical management of peri-implantitis. MATERIALS AND METHODS: An observational retrospective study was conducted to describe the possible effect of lesions of origin pulpar and/or periapical success or failure of the implant. The sample consisted of review of 800 implants, of which 500 were conducted at the Faculty of Dentistry of the UANL and 300 private clinics of Maxillofacial surgeons experienced in the placement of those who reside in Monterrey, Mexico. Five hundred and eighty cases correspond to female patients while that 220 patients of the male gender. The age of patients at the time of placing the implant ranged from 28 to 81 years. RESULTS: Of 800 study subjects who underwent dental implant treatments, 200 cases (25%) were detected which presented endodontic failure prior and/or adjacent to the placement of the implant. The 50.41% had peri-implantitis, recording 62 cases in the Faculty and 18 cases (23.38%) in private clinics, finding that there was a statistically significant difference between the presence and absence of peri-implantitis in terms of failed endodontic prior and/or adjacent to the placement of the implant. CONCLUSIONS: Within the limitations of this observational retrospective study, it could be concluded that the development of inflammatory changes mediated by the presence of remnant bacteria surrounding hard tissues adjacent to implants might induce late failures of implants, and potentially trigger pathological features of apical peri-implantitis.