Immediate loading of implants installed in a healed alveolar bony ridge or immediately after tooth extraction: an experimental study in dogs

ObjectiveTo compare the sequential healing at immediately loaded implants installed in a healed alveolar bony ridge or immediately after tooth extraction.Material and methodsIn the mandible of 12 dogs, the second premolars were extracted. After 3months, the mesial roots of the third premolars were endodontically treated and the distal roots extracted. Implants were placed immediately into the extraction sockets (test) and in the second premolar region (control). Crowns were applied at the second and third maxillary premolars, and healing abutments of appropriate length were applied at both implants placed in the mandible and adapted to allow occlusal contacts with the crowns in the maxilla. The time of surgery and time of sacrifices were planned in such a way to obtain biopsies representing the healing after 1 and 2weeks and 1 and 3months. Ground sections were prepared for histological analyses.ResultsAt the control sites, a resorption of the buccal bone of 1mm was found after 1week and remained stable thereafter. At the test sites, the resorption was 0.4mm at 1-week period and further loss was observed after 1month. The height of the peri-implant soft tissue was 3.8mm both at test and control sites. Higher values of mineralized bone-to-implant contact and bone density were seen at the controls compared with the test sites. The differences, however, were not statistically significant.ConclusionsDifferent patterns of sequential early healing were found at implants installed in healed alveolar bone or in alveolar sockets immediately after tooth extractions. However, three months after implant installation, no statistically significant differences were found for the hard- and soft-tissue dimensions.

Sub-crestal positioning of implants results in higher bony crest resorption: an experimental study in dogs

To compare peri-implant soft- and hard-tissue integration at implants installed juxta- or sub-crestally. Furthermore, differences in the hard and soft peri-implant tissue dimensions at sites prepared with drills or sonic instruments were to be evaluated. Three months after tooth extraction in six dogs, recipient sites were prepared in both sides of the mandible using conventional drills or a sonic device (Sonosurgery(®) ). Two implants with a 1.7-mm high-polished neck were installed, one with the rough/smooth surface interface placed at the level of the buccal bony crest (control) and the second placed 1.3 mm deeper (test). After 8 weeks of non-submerged healing, biopsies were harvested and ground sections prepared for histological evaluation. The buccal distances between the abutment/fixture junction (AF) and the most coronal level of osseointegration (B) were 1.6 ± 0.6 and 2.4 ± 0.4 mm; between AF and the top of the bony crest (C), they were 1.4 ± 0.4 and 2.2 ± 0.2 mm at the test and control sites, respectively. The top of the peri-implant mucosa (PM) was located more coronally at the test (1.2 ± 0.6 mm) compared to the control sites (0.6 ± 0.5 mm). However, when the original position of the bony crest was taken into account, a higher bone loss and a more apical position of the peri-implant mucosa resulted at the test sites. The placement of implants into a sub-crestal location resulted in a higher vertical buccal bone resorption and a more apical position of the peri-implant mucosa in relation to the level of the bony crest at implant installation. Moreover, peri-implant hard-tissue dimensions were similar at sites prepared with either drills or Sonosurgery(®) .

A utilização de abutment de zircônia na reabilitação oral: aspectos protéticos e periodontais

Zirconia abutments are used to obtain satisfactory aesthetic results in implant fixed anterior prostheses when metal abutments promote a grayish mucosal discoloration of the peri-implant soft tissues. However, there is a lack of studies to confirm the clinical performance of the peri-implant soft tissues surrouding zirconia abutments. This study described a case report of a patient treated with implant fixed all-ceramic crown made out on zirconia abutment after 3 years of followup. A 47-year-old female patient was admitted to the dental clinic (Aracatuba Dental School) complaining about the fracture of her implant fixed single crown in the region of the left lateral incisor. The patient chose the replacement of the fractured prosthesis for an allceramic crown. After 3 years of follow-up it was observed that maintenance of the aesthetic results and the peri-implant soft tissue without any inflammation or gingival recessions. Within the limitations of a case report, it can be conclude that zirconia abutments is a effective rehabilitation treatment because it preserves the aesthetics and function through the maintenance of peri-implant tissues.

Outcome evaluation of early placed maxillary anterior single-tooth implants using objective esthetic criteria: a cross-sectional, retrospective study in 45 patients with a 2- to 4-year follow-up using pink and white esthetic scores

BACKGROUND: To validate the concept of early implant placement for use in the esthetically sensitive anterior maxilla, clinical trials should ideally include objective esthetic criteria when assessing outcome parameters. METHODS: In this cross-sectional, retrospective 2- to 4-year study involving 45 patients treated with maxillary anterior single-tooth implants according to the concept of early implant placement, a novel comprehensive index, comprising pink esthetic score and white esthetic score (PES/WES; the highest possible combined score is 20), was applied for the objective esthetic outcome assessment of anterior single-tooth implants. RESULTS: All 45 anterior maxillary single-tooth implants fulfilled strict success criteria for dental implants with regard to osseointegration, including the absence of peri-implant radiolucency, implant mobility, suppuration, and pain. The mean total PES/WES was 14.7 +/- 1.18 (range: 11 to 18). The mean total PES of 7.8 +/- 0.88 (range: 6 to 9) documents favorable overall peri-implant soft tissue conditions. The two PES variables facial mucosa curvature (1.9 +/- 0.29) and facial mucosa level (1.8 +/- 0.42) had the highest mean values, whereas the combination variable root convexity/soft tissue color and texture (1.2 +/- 0.53) proved to be the most difficult to fully satisfy. Mean scores were 1.6 +/- 0.5 for the mesial papilla and 1.3 +/- 0.5 for the distal papilla. A mean value of 6.9 +/- 1.47 (range: 4 to 10) was calculated for WES. CONCLUSIONS: This study demonstrated that anterior maxillary single-tooth replacement, according to the concept of early implant placement, is a successful and predictable treatment modality, in general, and from an esthetic point of view, in particular. The suitability of the PES/WES index for the objective outcome assessment of the esthetic dimension of anterior single-tooth implants was confirmed. However, prospective clinical trials are needed to further validate and refine this index.

Soft and hard tissue histologic dimensions around dental implants in the canine restored with smaller-diameter abutments: a paradigm shift in peri-implant biology

PURPOSE To evaluate the biologic width dimensions around implants with nonmatching implant-abutment diameters. MATERIALS AND METHODS Five canines had their mandibular premolars and first molars removed bilaterally and replaced with 12 implants that had nonmatching implant-abutment diameters. On one side, six implants were placed in a submerged surgical approach, and the other side utilized a nonsubmerged approach. Two of the implants on each side were placed either 1 mm above, even with, or 1 mm below the alveolar crest. Two months later, gold crowns were attached, and the dogs were sacrificed 6 months postloading. Block sections were processed for histologic and histomorphometric analyses. RESULTS The bone level, connective tissue length, epithelial dimension, and biologic width were not significantly different when the implants were initially placed in a submerged or nonsubmerged surgical approach. The bone level was significantly different around implants placed 1 mm above the crest compared to implants placed even with or 1 mm below the alveolar crest. The connective tissue dimension was not different for any implant level placement. The epithelial dimension and biologic width were significantly greater for implants placed 1 mm below the alveolar crest compared to implants placed even with or 1 mm above the alveolar crest. For five of six implant placements, connective tissue covered the implant/abutment interface. CONCLUSIONS This study reveals a fundamental change in the biologic response to implants with nonmatching implant-abutment diameters. Unlike implants with matching implant-abutment diameters, the connective tissue extended coronally past the interface (microgap). This morphologic tissue alteration represents a significant change in the biologic reaction to implant-abutment interfaces and suggests that marginal inflammation is eliminated or greatly reduced in these implant designs.

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.

Influence of buccal bony crest width on marginal dimensions of peri-implant hard and soft tissues after implant installation. An experimental study in dogs

Aim: To evaluate the influence of the width of the buccal bony wall on hard and soft tissue dimensions following implant installation. Material and methods: Mandibular premolars and first molars of six Labrador dogs were extracted bilaterally. After 3 months of healing, two recipient sites, one on each side of the mandible, were prepared in such a way as to obtain a buccal bony ridge width of about 2 mm in the right (control) and 1 mm in the left sides (test), respectively. Implants were installed with the coronal margin flush with the buccal alveolar bony crest. Abutments were placed and the flaps were sutured to allow a non-submerged healing. After 3 months, the animals were euthanized and ground sections obtained. Results: All implants were completely osseointegrated. In respect to the coronal rough margin of the implant, the most coronal bone-to-implant contact was apically located 1.04 ± 0.91 and 0.94 ± 0.87 mm at the test and control sites, respectively, whereas the top of the bony crest was located 0.30 ± 0.40 mm at the test and 0.57 ± 0.49 mm at the control sites. No statistically significant differences were found. A larger horizontal bone resorption, however, evaluated 1 mm apically to the rough margin, was found at the control (1.1 ± 0.7 mm) compared to the test (0.3 ± 0.3 mm) sites, the difference being statistically significant. A thin peri-implant mucosa (2.4-2.6 mm) was found at implant installation while, after 3 months of healing, a biological width of 3.90-4.40 mm was observed with no statistically significant differences between control and test sites. Conclusions: A width of the buccal bony wall of 1or 2 mm at implant sites yielded similar results after 3 months of healing in relation of hard tissue and soft tissues dimensions after implant installation. © 2012 John Wiley & Sons A/S.

Experimental peri-implant tissue breakdown around different dental implant surfaces: Clinical and radiographic evaluation in dogs

Purpose: Tissue reactions to 4 different implant surfaces were evaluated in regard to the development and progression of ligature-induced peri-implantitis. Materials and Methods: In 6 male mongrel dogs, a total of 36 dental implants with different surfaces (9 titanium plasma-sprayed, 9 hydroxyapatite-coated, 9 acid-etched, and 9 commercially pure titanium) were placed 3 months after mandibular premolar extraction. After 3 months with optimal plaque control, abutment connection was performed. Forty-five days later, cotton ligatures were placed around the implants to induce peri-implantitis. At baseline and 20, 40, and 60 days after placement, the presence of plaque, peri-implant mucosal redness, bleeding on probing, probing depth, clinical attachment loss, mobility, vertical bone loss, and horizontal bone loss were assessed. Results: The results did not show significant differences among the surfaces for any parameter during the study (P > .05). All surfaces were equally susceptible to ligature-induced peri-implantitis over time (P < .001). Correlation analysis revealed a statistically significant relationship between width of keratinized tissue and vertical bone loss (r 2 = 0.81; P = .014) and between mobility and vertical bone loss (r 2 = 0.66; P = .04), both for the titanium plasma-sprayed surface. Discussion and Conclusions: The present data suggest that all surfaces were equally susceptible to experimental peri-implantitis after a 60-day period.

Hard and soft tissue changes around implants installed in regular-sized and reduced alveolar bony ridges. An experimental study in dogs

Objective: To study bony and soft tissue changes at implants installed in alveolar bony ridges of different widths.Material and methods: In 6 Labrador dogs, the mandibular premolars and first molars were extracted, and a buccal defect was created in the left side at the third and fourth premolars by removing the buccal bone and the inter-radicular and interdental septa. Three months after tooth extraction, full-thickness mucoperiosteal flaps were elevated, and implants were installed, two at the reduced (test) and two at the regular-sized ridges (control). Narrow or wide abutments were affixed to the implants. After 3 months, biopsies were harvested, and ground sections prepared for histological evaluation.Results: A higher vertical buccal bony crest resorption was found at the test (1.5 +/- 0.7 mm and 1.0 +/- 0.7 mm) compared to the control implants (1.0 +/- 0.5 mm and 0.7 +/- 0.4 mm), for both wide and narrow abutment sites. A higher horizontal alveolar resorption was identified at the control compared to the test implants. The difference was significant for narrow abutment sites. The peri-implant mucosa was more coronally positioned at the narrow abutment, in the test sites, while for the control sites, the mucosal adaptation was more coronal at the wide abutment sites. These differences, however, did not reach statistical significance.Conclusions: Implants installed in regular-sized alveolar ridges had a higher horizontal, but a lower vertical buccal bony crest resorption compared to implants installed in reduced alveolar ridges. Narrow abutments in reduced ridges as well as wide abutments in regular-sized ridges yielded less soft tissue recession compared to their counterparts.

Effect of mechanical and antiseptic therapy on peri-implant mucositis: an experimental study in monkeys

OBJECTIVES: This experiment was performed to evaluate clinically and histologically the effect of mechanical therapy with or without antiseptic therapy on peri-implant mucositis lesions in nine cynomolgus monkeys. MATERIAL AND METHODS: Two ITI titanium implants were inserted into each side of the mandibles. After 90 days of plaque control and soft tissue healing, a baseline clinical examination was completed. Peri-implant lesions were induced by placing silk ligatures and allowing plaque to accumulate for 6 weeks. The clinical examination was then repeated, and the monkeys were randomly assigned to three treatment groups: group A, mechanical cleansing only; group B, mechanical cleansing and local irrigation with 0.12% chlorhexidine (CHX) and application of 0.2% CHX gel; and group C, control, no treatment. The implants in treatment groups A and B were treated and maintained according to the assigned treatment for two additional months. At the end of the maintenance period, a final clinical examination was performed and the animals were sacrificed for biopsies. RESULTS: The mean probing depths (PD) values at mucositis were: 3.5, 3.7, and 3.4 mm, and clinical attachment level (CAL) = 3.8, 4.1, and 3.9 mm for treatment groups A, B and C, respectively. The corresponding values after treatment were: PD = 1.7, 2.1, and 2.5 mm, and CAL=2.6, 2.6, and 3.1 mm. ANOVA of mean changes (Delta) in PD and CAL after treatment showed no statistical difference between the treatment groups. Comparison of the mean changes in PD and CAL after treatment yielded statistical differences between the control and treatment groups P < 0.01. According to the t-test, no statistical difference was found between treatment groups A and B for the PD reduction but there was a significant difference for the CAL change, P < 0.03. Group A had significantly more recession and less CAL gain than group B. Non-parametric tests yielded no significant differences in modified plaque index (mPlI) and gingival index (GI) after treatment between both treatment groups. Frequencies and percent distributions of the mPlI and GI scores changed considerably for both treatment groups when compared with the changes in the control group after treatment. With regard to the histological evaluation, no statistical differences existed between the treatments for any linear measurement. The proportion of inflammation found in the mucosal tissues of the control implants was greater than the one found for both treatment groups, P < 0.01. More importantly, both treatment groups showed a similar low proportion of inflammation after 2 months of treatment. CONCLUSIONS: Within the limitations of this experiment, and considering the supportive plaque control rendered, it can be concluded that for pockets of 3-4 mm: (1) mechanical therapy alone or combined with CHX results in the clinical resolution of peri-implant mucositis lesions, (2) histologically, both treatments result in minimal inflammation compatible with health, and (3) the mechanical effect alone is sufficient to achieve clinical and histologic resolution of mucositis lesions.

Morphogenesis of the peri-implant mucosa: an experimental study in dogs

PURPOSE: The objective of the present experiment was to study the morphogenesis of the mucosal attachment to implants made of c.p. titanium. MATERIAL AND METHODS: All mandibular premolars were extracted in 20 Labrador dogs. After a healing period of 3 months, four implants (ITI Dental Implant System) were placed in the right and left sides of the mandible. A non-submerged implant installation technique was used and the mucosal tissues were secured to the conical marginal portion of the implants with interrupted sutures. The sutures were removed after 2 weeks and a plaque control program including daily cleaning of the remaining teeth and the implants was initiated. The animals were sacrificed and biopsies were obtained at various intervals to provide healing periods extending from Day 0 (2 h) to 12 weeks. The mandibles were removed and placed in the fixative. The implant sites were dissected using a diamond saw and processed for histological analysis. RESULTS: Large numbers of neutrophils infiltrated and degraded the coagulum that occupied the compartment between the mucosa and the implant during the initial phase of healing. At 2 weeks after surgery, fibroblasts were the dominating cell population in the connective tissue interface but at 4 weeks the density of fibroblasts had decreased. Furthermore, the first signs of epithelial proliferation were observed in specimens representing 1-2 weeks of healing and a mature barrier epithelium occurred after 6-8 weeks of healing. The collagen fibers of the mucosa were organized after 4-6 weeks of healing. CONCLUSION: It is suggested that the soft-tissue attachment to implants placed using a non-submerged installation procedure is properly established after several weeks following surgery.

Enlargement of keratinized peri-implant mucosa at the time of second stage surgery (re-entry)

A tightly attached keratinized mucosa around endosseous dental implants is believed to be protective against peri-implant bone loss. Tension caused by buccal frena and mobile non keratinized mucosa is to avoid. This case report documents the optimization of peri-implant mucosal conditions in the upper and lower jaw. At the time of second stage surgery (re-entry) at submucosally osseointegrated dental implants an enlargement of keratinized mucosa and a thickening of soft tissue was obtained administrating a vestibuloplasty combined by a free gingival graft or a vestibuloplasty combined by an apically moved flap.

Periodontal and peri-implant wound healing following laser therapy

Laser irradiation has numerous favorable characteristics, such as ablation or vaporization, hemostasis, biostimulation (photobiomodulation) and microbial inhibition and destruction, which induce various beneficial therapeutic effects and biological responses. Therefore, the use of lasers is considered effective and suitable for treating a variety of inflammatory and infectious oral conditions. The CO2 , neodymium-doped yttrium-aluminium-garnet (Nd:YAG) and diode lasers have mainly been used for periodontal soft-tissue management. With development of the erbium-doped yttrium-aluminium-garnet (Er:YAG) and erbium, chromium-doped yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers, which can be applied not only on soft tissues but also on dental hard tissues, the application of lasers dramatically expanded from periodontal soft-tissue management to hard-tissue treatment. Currently, various periodontal tissues (such as gingiva, tooth roots and bone tissue), as well as titanium implant surfaces, can be treated with lasers, and a variety of dental laser systems are being employed for the management of periodontal and peri-implant diseases. In periodontics, mechanical therapy has conventionally been the mainstream of treatment; however, complete bacterial eradication and/or optimal wound healing may not be necessarily achieved with conventional mechanical therapy alone. Consequently, in addition to chemotherapy consisting of antibiotics and anti-inflammatory agents, phototherapy using lasers and light-emitting diodes has been gradually integrated with mechanical therapy to enhance subsequent wound healing by achieving thorough debridement, decontamination and tissue stimulation. With increasing evidence of benefits, therapies with low- and high-level lasers play an important role in wound healing/tissue regeneration in the treatment of periodontal and peri-implant diseases. This article discusses the outcomes of laser therapy in soft-tissue management, periodontal nonsurgical and surgical treatment, osseous surgery and peri-implant treatment, focusing on postoperative wound healing of periodontal and peri-implant tissues, based on scientific evidence from currently available basic and clinical studies, as well as on case reports.