Immediate implantation in fresh extraction sockets. A controlled clinical and histological study in man

Tissue Healing Around Dental Implants With Marginal Bone Defects With and Without Flap Elevation: An Experimental Study in Dogs

The technique of immediate implant placement after extraction has been conceived for preserving residual bone support and soft tissue morphology. Today, this procedure is still unpredictable and presents inconveniences for both the patient and the dentist. Therefore, the healing process around a dental implant placed into an extraction socket needs to be deeply investigated to increase the predictability of this surgical approach. The aim of the present investigation was to evaluate the healing of bone defects (fresh extraction sockets) after implant installation with flap elevation, and primary closure compared with implant installation without flap elevation. This study use histologic and histomorphometric analyses to evaluate tissue healing around dental implants with marginal bone defects with and without flap elevation 1 week, 4 weeks, and 12 weeks after implantation in the dogs. The main qualitative findings showed that after 1 week of implantation almost no bone repair was observed, and there was no significant difference between the 2 groups in terms of bone-healing performance, inflammatory infiltrates (slight to moderate grade), and bone resorption (moderate to marked grade) limited to the coronal portion of the implanted sites. The 2 groups with or without flap elevation behaved similarly at this point of implantation. Under the experimental conditions of this study, no biological differences were observed between the 2 groups with and without flap elevation in terms of crestal bone repair, inflammation, marginal bone loss, and soft tissue downgrowth. The qualitative differences observed might be imputable to fortuitous events. The histomorphometric measurements confirmed the qualitative trends observed. The limitations of this study, as with all animal studies, are its translational aspects. Investigation of the same topic in a human population by setting up a controlled, randomized, prospective trial including a sufficient amount of patients investigated according to the split-mouth method would be beneficial.

Alterations of the bone dimension following immediate implant placement into extraction socket: systematic review and meta-analysis

AIM

This systematic review was aimed at analysing bone dimensional alterations within the first year following immediate implant placement.

MATERIALS AND METHODS

The electronic search was conducted using MEDLINE (PubMed), Cochrane Central Register of Controlled Trials (CENTRAL) and EMBASE from January 1980 to October 2013. Quality assessment of selected articles was performed using Cochrane Collaboration's tool or Newcastle-Ottawa scale according to the design of each study. A meta-analysis was performed to estimate bone dimensional reduction. Weighted mean differences in bone dimension between baseline and follow-up measurement were calculated. Subgroup analysis and mete-regression were conducted to evaluate the effects of different variables.

RESULTS

A total of 1348 articles were identified following the search process. Six studies were included in the present review. The weighted mean buccal horizontal bone dimensional reduction (BHDr) was 1.07 mm and buccal vertical bone dimensional reduction (BVDr) was 0.78 mm. The weighted mean palatal bone dimensional reduction was 0.62 mm horizontally (PHDr) and 0.50 mm vertically (PVDr). The initial thickness of the buccal alveolar plate (TB) of the socket was the only variable significantly correlated with BHDr and BVDr in meta-regression analysis.

CONCLUSIONS

The bone dimensions of immediate implant sites demonstrated approximately 0.5-1.0 mm reduction in vertical and horizontal aspects 4-12 months following surgery. The results should be interpreted with care because of the data heterogeneity. The correlation of the socket buccal wall thickness, and other variables, with dimensional changes of the bony ridge should be investigated further in controlled clinical trials.

Fate of the buccal bone at implants placed early, delayed, or late after tooth extraction analyzed by cone beam CT: 10-year results from a randomized, controlled, clinical study

AIM

To present 10-year cone beam CT (CBCT) data on the fate of buccal bone at single-tooth implants placed early, delayed, or late after tooth extraction.

MATERIAL AND METHODS

Sixty-three of 72 patients, originally randomly allocated to three equal-size groups, received a single-tooth implant on average 10 days (Ea; N = 22), 3 months (De; N = 22), or 1.5 years (La; N = 19) after tooth extraction. Healing abutments were mounted after a 3-month period of submerged healing and metalceramic crowns were cemented after one additional month. At the second stage surgery, presence of buccal bone defects (dehiscences or intrabony) and their dimensions were registered. CBCT scans recorded with a Scanora(®) 3D unit and standardized periapical (PA) radiographs of the implants were obtained at the 10-year control. Interproximal bone levels (i.e., the distance from the implant platform to the first bone-to-implant contact; BIC) measured in CBCT image sections and PA were compared, and the buccal bone level was determined in the CBCT images.

RESULTS

Two Ea and one De implants failed to osseointegrate. Forty-nine patients attended the 10-year control and due to poor quality of 5 CBCT scans, useful CBCT images were available from 44 patients (Ea:12, De:17, La:15). No significant differences between CBCT and PA images in measurements of the interproximal bone levels were observed. Ten years after implant placement, BIC at the buccal aspect was located on average 2 mm apically to the implant platform (2.39 ± 1.06 mm [median = 2.36] for Ea, 2.22 ± 0.99 mm [median = 2.16] for De, and 1.85 ± 0.65 mm [median = 1.95] for La implants) with no significant difference among the groups (P = 0.20). Mean buccal bone level (bBL) for implants with an intrabony or a dehiscence defect at second stage surgery was 2.51 ± 1.12 mm [median = 2.70] and 2.84 ± 0.70 mm [median = 2.79], respectively, while 1.78 ± 0.74 mm [median = 1.93] for the implants with no defect. The difference in bBL between the implants without a defect and those with a dehiscence was significant at 10 years (P = 0.0005).

CONCLUSION

Time of placement of single-tooth implants after tooth extraction did not significantly influence the peri-implant buccal bone level, while presence of a buccal bone dehiscence at second stage surgery resulted in significantly more apically located BIC buccally at 10 years.

Influence of the implant design on osseointegration and crestal bone resorption of immediate implants: a histomorphometric study in dogs

PURPOSE

The aim of this study was to evaluate bone-to-implant contact after immediate implant placement at different levels in relation to crestal bone in American foxhound dogs.

MATERIALS AND METHODS

The mandibular second, third, and fourth premolars of six American foxhound dogs were extracted bilaterally. Randomly, three immediate implants were placed in the hemimandible of each dog at the bone crest (control group) or 2 mm subcrestally (test group). Three dogs were allowed an 8-week healing period; the other three were left a 12-week healing period. After healing periods, histomorphometric analyses of the specimens were carried out to measure BIC values and bone remodeling.

RESULTS

All implants healed uneventfully and were available for histological analysis. The total BIC mean values were 44.52% (± 8.67) and 39.50% (± 9.25) at 8 and 12 weeks, respectively, for the control group, and 47.33% (± 5.23) and 53.85% (± 4.21) at 8 and 12 weeks after healing for the test group, respectively. There was observed less bone resorption in the group of implants placed subcrestally.

CONCLUSION

Our findings suggest that less resorption may be expected when implants are inserted 2 mm subcrestally. Moreover, higher BIC values in the group of subcrestal implants were found.

Ridge alterations following grafting of fresh extraction sockets in man. A randomized clinical trial

OBJECTIVE

To evaluate dimensional alterations of the alveolar ridge that occurred following tooth extraction at sites grafted with Bio-Oss(®) Collagen.

MATERIAL AND METHODS

Twenty-eight subjects with maxillary incisors, canines, and premolars scheduled for extraction were included. The tooth was carefully removed. The patients were randomly assigned to a test or a control group. In the test group patients, Bio-Oss(®) Collagen was placed in the fresh extraction socket while in the controls no grafting was performed. Radiographic examination (cone beam computed tomograms, CBCT) was performed immediately after tooth extraction and socket treatment. Four months later, a new CBCT was obtained. In the radiographs, (i) the distance (mm) between base of the alveolar process (apex) and the buccal and palatal crests was determined, (ii) the outer profile of alveolar process of the experimental sites was outlined, and the cross section of the area (mm(2) ) determined.

RESULTS

After 4 months of healing, the buccal and to a less extent also the palatal bone plate had become markedly reduced in height. The placement of a biomaterial in the socket failed to prevent resorption of the buccal and palatal bone walls. The cross-sectional area of the control ridge was reduced about 25% and of the test ridge with 3%.

CONCLUSION

The placement of a xenograft in fresh extraction sockets markedly counteracted the reduction in the hard tissue component of the edentulous sites.

Novel hybrid drilling protocol: evaluation for the implant healing--thermal changes, crestal bone loss, and bone-to-implant contact

OBJECTIVES

To evaluate a new hybrid drilling protocol, by the analysis of thermal changes in vitro, and their effects in the crestal bone loss and bone-to-implant contact in vivo.

MATERIALS AND METHODS

Temperature changes during simulated osteotomies with a hybrid drilling technique (biologic plus simplified) (test) versus an incremental drilling technique (control) were investigated. One hundred and twenty random osteotomies were performed (60 by group) in pig ribs up to 3.75-mm-diameter drill to a depth of 10 mm. Thermal changes and time were recorded by paired thermocouples. In a parallel experiment, bilateral mandibular premolars P2, P3, P4, and first molar M1 were extracted from six dogs. After 2-month healing, implant sites were randomly prepared using either of the drilling techniques. Forty eight implants of 3.75 mm diameter and 10 mm length were inserted. The dogs were euthanized at 30 and 90 days, and crestal bone loss (CBL) and bone-to-implant contact (BIC) were evaluated.

RESULTS

The control group showed maximum temperatures of 35.3 °C ± 1.8 °C, ΔT of 10.4 °C, and a mean time of 100 s/procedure; meanwhile, the test group showed maximum temperatures of 36.7 °C ± 1.2 °C, ΔT of 8.1 °C, and a mean time of 240 s/procedure. After 30 days, CBL values for both groups (test: 1.168 ± 0.194 mm; control: 1.181 ± 0.113 mm) and BIC values (test: 43 ± 2.8%; control: 45 ± 1.3%) were similar, without significant differences (P > 0.05). After 90 days, CBL (test: 1.173 ± 0.187 mm; control: 1.205 ± 0.122 mm) and BIC (test: 64 ± 3.3%; control: 64 ± 2.4%) values were similar, without significant differences (P > 0.05). The BIC values were increased at 90 days in both groups compared with the 30-day period (P < 0.05).

CONCLUSIONS

Within the limitations of this study, the new hybrid protocol for the preparation of the implant bed without irrigation, increase the temperature similarly to the incremental conventional protocol, and requires twice the time for the completion of the drilling procedure in vitro. Crestal bone loss and bone-to-implant contact in the hybrid drilling protocol are comparable with the conventional drilling protocol and do not affect the osseointegration process in vivo.

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.

A 5-year comparison of marginal bone level following immediate loading of single-tooth implants placed in healed alveolar ridges and extraction sockets in the maxilla

PURPOSE

The aim of present investigation was to evaluate marginal bone level after 5-year follow-up of implants placed in healed ridges and fresh extraction sockets in maxilla with immediate loading protocol.

MATERIALS AND METHODS

Thirty-six patients in need of a single-tooth replacement in the anterior maxilla received 42 Astra Tech implants (Astra Tech Implant system™, Dentsply Implants, Mölndal, Sweden). Implants were placed either in healed ridges (group I) or immediately into fresh extraction sockets (group II). Implants were restored and placed into functional loading immediately by using a prefabricated abutment. Marginal bone level relative to the implant reference point was recorded at implant placement, crown cementation, 12, 36, and 60 months following loading using intra-oral radiographs. Measurements were made on the mesial and distal sides of each implant.

RESULTS

Overall, two implants were lost from the group II, before final crown cementation: they were excluded from the study. The mean change in marginal bone loss (MBL) after implant placement was 0.26 ± 0.161 mm for 1 year, and 0.26 ± 0.171 mm for 3 years, and 0.21 ± 0.185 mm for 5 years in extraction sockets and was 0.26 ± 0.176 mm for 1 year and 0.21 ± 0.175 mm for 3 years, and 0.19 ± 0.172 mm for 5 years in healed ridges group. Significant reduction of marginal bone was more pronounced in implants inserted in healed ridges (P < 0.041) compared to fresh surgical extraction sockets (P < 0.540). Significant MBL was observed on the mesial side of the implant after cementation of the provisional (P < 0.007) and after 12 months (P < 0.034) compared to the distal side which remained stable for 3 and 5 years observation period.

CONCLUSIONS

Within the limitations of this study, responses of local bone to immediately loaded implants placed either in extraction sockets or healed ridges were similar. Functional loading technique by using prefabricated abutment placed during the surgery time seems to maintain marginal bone around implant in both healed and fresh extraction sites.

Comparison of implant stability before prosthetic loading of two dental implant systems

Dental implantology is the state of the art technique to replace missing teeth. Implant stability of implant jeopardizes its longevity and success of treatment. This study evaluates the implant stability of implant before and after 4 months of the implant placement, but before prosthetically loading it. Ten two-stage implants of Life care and Nobel Biocare dental implants were placed in 20 patients. Digital OPG was taken on the day of implant placement. After 4 months, at the time of second stage surgery, the implant stability was evaluated by the Periotest instrument. Four months after the implant placement, Periotest evaluation showed a mean of 1.9, which indicated that implants were well osseointegrated and stable. Even before prosthetically loading the two-stage implant, crestal bone loss of 0.6-0.9 mm occurred around the implant. The smooth polished collar design of the implant may have contributed to crestal bone loss.

Use of sintered xenograft over allograft for ridge augmentation: technique note

Patients often present with tooth or implant complications with loss of significant bone width and the need for bone volume for implant placement and maintenance of ridge contour for esthetics. The technique described is a low-morbidity, highly predictable method to restore these sites. A case series of 12 patients followed for 2 years is presented.

Immediate provisionalization and nonfunctional loading of a single implant in the maxillary esthetic zone: a clinical presentation and parameters for consideration

Restoration of single tooth loss with implant supported prosthesis is now considered a highly predictable treatment. However, the maxillary anterior region still presents a challenge for both the prosthodontist and the periodontist because of the inherent difficulties encountered in the provisionalization and harmonic incorporation of the definitive prosthesis into patient's dentogingival complex. This paper presents a clinical case of a single implant placed immediately after the extraction of a maxillary central incisor, followed by immediate provisionalization and nonfunctional loading. The surgical and the restorative techniques are described, and the parameters of consideration for this approach are presented.

Morphometric analysis of maxillary alveolar regions for immediate implantation

PURPOSE

The purpose of this study was to provide an actual guideline in determining the shape, diameter, and position of the implant in immediate implantation by the measurement of the thickness of facial and palatal plate, the thickness of cortical bone on the facial and palatal plate, the diameter of the root, and the distance between the roots in the cadavers.

MATERIALS AND METHODS

The horizontal sections of 20 maxillae were measured and analyzed to obtain the average values. Resin blocks were produced and cut serially at 1 mm intervals from the cervical line to the root apex. Images of each section were obtained and the following measurements were performed: The thickness of the facial and palatal residual bone at each root surface, the thickness of the facial and palatal cortical bone at the interdental region, the diameter of all roots of each section on the faciopalatal and mesiodistal diameter, and the interroot distance. Three specimens with measurements close to the average values were chosen and 3-dimensional images were reconstructed.

RESULTS

The thickness of the facial and palatal cortical bone at the interdental region in the maxilla, the buccal cortical bone was thicker in the posterior region compared to the anterior region. The interroot distance of the alveolar bone thickness between the roots increased from anterior to posterior region and from coronal to apical in the maxilla.

CONCLUSION

In this study, the limited results of the morphometric analysis of the alveolar ridge using the sections of maxilla in the cadavers may offer the useful information when planning and selecting optimal implant for immediate implantation in the maxilla.

Ridge preservation after tooth extraction

BACKGROUND

Following tooth extraction, the alveolar ridge will undergo dimensional changes. This change may complicate the subsequent restorative procedure when oral implants are chosen. "Alveolar ridge preservation" has been assessed in various studies.

AIM

To evaluate the more recent studies on this topic and to explore new insights under this topic.

MATERIAL AND METHODS

Animal studies and clinical studies have addressed different techniques.

RESULTS AND CONCLUSIONS

Implants placed into the fresh extraction sockets do not prevent the resorption of the alveolar bone. Simultaneous guided bone regeneration could partially resolve alveolar bone resorption. The use of root-formed implants does not preserve alveolar ridges. Moreover, various bone substitutes have been tested: magnesium-enriched hydroxyapatite, human demineralized bone matrix, and deproteinized bovine bone mineral have been shown to be effective in ridge preservation. Applying the guided bone regeneration principle using bone substitutes together with a collagen membrane has shown clear effects on preserving alveolar ridge height as well as ridge width. Soft tissue grafts or primary closure did not show beneficial effect on preserving the alveolar bone.

The influence of the periodontal biotype on peri-implant tissues around immediate implants with and without xenografts. Clinical and micro-computerized tomographic study in small Beagle dogs

OBJECTIVE

Soft tissues and buccal bone plate remodeling after immediate implantation in sockets with thin buccal bone, using the flapless approach with or without bone graft into the buccal gap, was compared between sites with thin and normal gingiva.

MATERIAL AND METHODS

Eight dogs had the gingiva of one side of the mandible thinned, the mandibular premolars were extracted without flaps, and 4 implants were installed in each side, positioned 1.5 mm from the buccal bone. The sites were randomly assigned into: TG (test group) = thin gingiva; TG + GM (TG with grafting material); CG (control group) = normal gingiva; and CG + GM (CG with grafting material). Buccal bone thickness (BBT), thickness of keratinized tissue (TKT), alveolar thickness (AT), gingival recession (GR), and probing depth (PD) were clinically evaluated. Within 12 weeks the dogs were sacrificed and the samples were analyzed by micro-computerized tomography.

RESULTS

A thin BBT was observed in all the dogs. The presurgical procedures reduced TKT in the test group, with minimal changes of the AT. There were no statistically significant differences among the groups for the clinical parameters and the tomographic analysis showed similar linear and tri-dimensional bone reduction in all the groups.

CONCLUSION

The thickness of the buccal bone was a fundamental factor in buccal bone plate resorption, even with flapless implantation. The decrease in gingival thickness or the addition of a biomaterial in the gap did not influence the results.

Long-term results of implants immediately placed into extraction sockets grafted with β-tricalcium phosphate: a retrospective study

PURPOSE

The aim of this 10 year retrospective study was to evaluate the crestal bone loss around immediate implant placed in tricalcium phosphate (TCP) grafted extraction sockets

MATERIALS AND METHODS

Data were collected from files of 58 patients (33 females, 25 males, average age 54.78 years) undergoing immediate implant placement into fresh extraction socket with or without the use of TCP (Cerasorb, Curasan AG, Kleinostheim, Germany) grafting. After implant placement, horizontal gaps larger than 1.5 mm between the implant surface and the bony plate were grafted with TCP without the use of a membrane, while smaller gaps were not grafted. Two hundred fifty-four implants were inserted: 79 were placed immediately with the use of β-TCP as grafting material (group A), 175 were placed in healed extraction sites, with 61 implants placed with the use of β-TCP graft material (group B), and 114 implants were placed without any grafting material (group C). Bone loss recordings were performed using periapical radiography. Measurements were performed from the neck of the implant to level of the surrounding bone in the vertical dimension.

RESULTS

No implant was lost during the follow-up period. Statistical analysis showed no correlation between implant placement timing (delayed or immediate), the use of bone graft, and extent of bone loss.

CONCLUSION

The use of TCP (Cerasorb) as a grafting material during immediate implant placement allowed no bone loss in 72.1% of the implants, which was very similar to the nongrafted cases for which implants were placed in favorable conditions.

Crestal bone reactions to immediate implants placed at different levels in relation to crestal bone. A pilot study in Foxhound dogs

OBJECTIVES

The aim of the present study was to evaluate bone-to-implant contact (BIC) and bone remodeling dynamics after immediate implant placement at different levels in relation to the crestal bone.

MATERIALS AND METHODS

The mandibular second, third, and fourth premolars of six Foxhound dogs were extracted bilaterally. Randomly, three implants were immediately placed in the hemi-arches of each dog, crestally or 2 mm subcrestally. Three dogs were allowed an 8-week submerged healing period, and the other three at 12-week submerged healing period. The animals were sacrificed at 12 weeks and samples were obtained. Biopsies were processed for ground sectioning. Histomorphometric analysis was carried out to compare BIC, bone neoformation, and bone remodeling.

RESULTS

All implants osseointegrated clinically and histologically. Healing patterns examined microscopically at eight and twelve weeks for both groups (crestal and subcrestal) yielded similar qualitative bone findings. The Total BIC mean value for the crestal group 44.52% at 8 weeks and 39.50% at 12 weeks, and for the subcrestal group was 47.33% at 8 weeks and 53.85% at 12 weeks%. There was less bone resorption in the subcrestal group (test) than in crestal group (control).

CONCLUSIONS

Within the limitations of this study, our findings suggest that apical positioning of the top of the implant does not jeopardize bone crest and peri-implant tissue remodeling. However, less resorption of the lingual crest may be expected when implants are placed 2 mm subcrestally. Moreover, higher BIC values were found in implants placed subcrestally.

Immediate placement of implant in fresh extraction socket with early loading

Implant placement in maxillary anterior region has most aesthetic challenges in implant dentistry because tooth loss lead to bone resorption and collapse of gingival architecture, which lead to aesthetic compromise and inadequate bone for implant placement. Immediate implant placement into fresh extraction socket reduces the treatment time, cost, preserved the gingival aesthetic and increases the comfort of the patient. This article describes the procedure for immediate implant placement in fresh extraction socket and early loading of implant with zirconia crown. Clinical and radiographic examination revealed width and length of the tooth for selecting implant size and design. Cement retained zirconia crown was used for early loading. Implant was successfully loaded and was functional during 36 months follow up period. Immediate placement and early loading of dental implant provides advantages like fewer surgical procedures, shorter treatment time, and improved aesthetic and psychological confidence.

Bucco-Lingual Crestal Bone Changes Around Implants Immediately Placed in Fresh Extraction Sockets in Association or not With Porcine Bone: A Non-Blinded Randomized Controlled Trial in Humans

Background: The aim of the present randomized controlled clinical trial was to assess the bucco-lingual bone changes of implants immediately placed in fresh extraction sockets in association or not with porcine bone. Methods: Forty patients were included in the present study, and were randomly assigned to the control (n = 20) and test (n = 20) groups. Each patient received a single implant placed into an immediate extraction site of a molar or a first upper premolar with a flapless approach. In the control sites no grafting material was placed, while in the tests a deantigenated collagenated bone substitute of porcine origin was used to fill the gaps between the implant and the extraction socket. The bucco-lingual bone width was measured at different time points: at the time of surgery (T0), at 90 days (T1), at 110 days (T2) and after 6 months of masticatory function (T3). The values were statistically analyzed between and within the treatment groups (p>0.05). Results: All the implants were osseointegrated. Four control implants were excluded from the analysis due to the exposure of the coronal portion of the fixture. At T1, T2 and T3, statistically significant differences were found by comparing the mean width of the bucco-lingual bone between control and test groups. The mean values decreased during the observation period in both groups; statistically significant differences within controls were detected at T1, T2 and T3, and at T2 and T3 within tests. Conclusions: The outcomes of present study suggested that porcine bone enabled to avoid bucco-lingual crestal bone changes in implants immediately placed in fresh extraction sockets.

Dimensional Ridge Preservation with a Novel Highly Porous TiO(2) Scaffold: An Experimental Study in Minipigs

Despite being considered noncritical size defects, extraction sockets often require the use of bone grafts or bone graft substitutes in order to facilitate a stable implant site with an aesthetically pleasing mucosal architecture and prosthetic reconstruction. In the present study, the effect of novel TiO(2) scaffolds on dimensional ridge preservation was evaluated following their placement into surgically modified extraction sockets in the premolar region of minipig mandibles. After six weeks of healing, the scaffolds were wellintegrated in the alveolar bone, and the convex shape of the alveolar crest was preserved. The scaffolds were found to partially preserve the dimensions of the native buccal and lingual bone walls adjacent to the defect site. A tendency towards more pronounced vertical ridge resorption, particularly in the buccal bone wall of the nongrafted alveoli, indicates that the TiO(2) scaffold may be used for suppressing the loss of bone that normally follows tooth extraction.

Clinical evaluation of immediate implants using different types of bone augmentation materials

BACKGROUND

The immediate placement of implants into fresh extraction socket has proven to be a safe and predictable procedure. However, there is lack of scientific evidence regarding the healing pattern and osseointegration associated with immediate implants especially with different grafting materials.

METHODS

A total of 30 patients male or female, with a mean age of 23.1 years ± 6.0 in the age group of 18-38 years, each having at least one tooth indicated for extraction (either maxillary or mandibular anterior teeth) were selected and randomly divided in to two groups. 30 Implants (Xive(®) friadent, Germany) were placed into fresh extraction sockets during this study. Two types of graft materials namely Dembone(®) (freeze-dried bone allograft) for group A and G-Bone(®) (modified hydroxyapatite) for group B were used. After implant placement all implants were evaluated clinically and radiographically at baseline, 3 months, 6 months, 9 months and 12 months. All clinical and radiographic parameters were subjected to statistical analysis. Intragroup comparisons were made with paired 't' test and intergroup comparisons with unpaired 't' test (P > 0.05 NS, ≤0.05 S, ≤0.01 HS).

RESULT

During the 1-year interval, no implant was lost and the mean bone level at the implants was maintained or even improved.

CONCLUSION

Immediate restoration of single tooth implants placed in fresh extraction sockets could be considered a valuable option to replace a missing tooth. The graft materials used in both groups have been found to be equally effective.

Alveolar ridge resorption after tooth extraction: A consequence of a fundamental principle of bone physiology

It is well established that tooth extraction is followed by a reduction of the buccolingual as well as the apicocoronal dimension of the alveolar ridge. Different measures have been taken to avoid this bone modelling process, such as immediate implant placement and bone grafting, but in most cases with disappointing results. One fundamental principle of bone physiology is the adaptation of bone mass and bone structure to the levels and frequencies of strain. In the present article, it is shown that the reduction of the alveolar ridge dimensions after tooth extraction is a natural consequence of this physiological principle.

Immediate placement and restoration of implants in the aesthetic zone with a trimodal approach: soft tissue alterations and its relation to gingival biotype

PURPOSE

The aim of this prospective study was to evaluate the soft tissue changes around implants in the aesthetic zone, placed under a trimodal approach (immediate post-extraction placement, flapless, and immediate provisional restoration) and its relationship to gingival/periodontal biotype of the patient.

MATERIALS AND METHODS

The sample consisted of 14 patients from two private practices that were in need of a tooth extraction in the anterior maxillary region (cuspid to cuspid) and were candidates to a replacement with a dental implant. An initial measurement (baseline) of the position or the mesial and distal papillae and gingival zenith was made at this time, with a rigid dental-supported stent and an electronic precision caliper, able to the second tenth of a millimeter; after careful tooth extraction, the periodontal thickness, at a point 5 mm apical to de gingival buccal margin, with an analogical thickness gauge, able to one tenth of a millimeter. Once the implant was inserted an immediate provisional restoration was delivered. To evaluate the soft tissue changes measurements were repeated at 3, 6, and 12 months. A statistical analysis was performed to evaluate the changes in the gingival margin around the implant restorations and to identify a possible correlation to patient's periodontal thickness.

RESULTS

All 14 patients received Straumann (®) implants (9 Tissue Level [TL] Regular Neck [RN], 2 TL Narrow Neck [NN], 2 Bone Level [BL] Narrow Crossfit [NC], and 1 BL Regular Crossfit [RC]). All implants integrated and none had any biological complications. Three provisional restorations presented screw loosening and retightened once and one loss retention and was recemented once. In one patient, with a severe bruxing habit, the final restoration suffered screw loosening and was retightened. Of the final restorations, 12 were screw-retained and 2 cemented on custom-made Zirconia abutments. A mean recession of the buccal margin of 0.45 mm was recorded at 12 months ( ± 0.25 mm). An acceptable papilla level was present in all cases at 1 year, with mean changes of 0.38 mm ( ± 0.60) for the mesial and 0.80 mm ( ± 0.90) of the distal papilla, respectively. No correlation could be established between the soft tissue changes and the periodontal biotype of the patient.

CONCLUSIONS

Within the limitations of this study, the good aesthetic outcome and minimal complications seem to validate the trimodal approach protocol as a reliable and simple protocol to place and restore immediate implants in the aesthetic zone. No correlation between the patient's gingival biotype and the soft tissue alterations could be established. Additional studies are needed to verify long-term aesthetic results with this approach and to better define and quantify biotypes.

Immediate placement and functional loading of implants on canine with fixed partial denture for a patient having canine protected occlusion: a case report

Conventional implant protocols required a load-free healing period of three to six months between placement and functional loading of the implants. Many efforts have been made to minimize the duration of treatment time. Several literatures have documented immediate function with provisional or definitive prosthesis within a week of the placement in response to these demands. In addition, immediate implant placement has advantages such as shortened treatment time and preservation of soft tissue architectures. This article presents immediate implant placement into fresh extraction sockets followed by functional immediate loading with provisional prosthesis on canine and premolars for a patient having canine protected occlusion.

Surgical protocols for ridge preservation after tooth extraction. A systematic review

OBJECTIVE

This systematic review aims to evaluate the scientific evidence on the efficacy in the surgical protocols designed for preserving the alveolar ridge after tooth extraction and to evaluate how these techniques affect the placement of dental implants and the final implant supported restoration.

MATERIAL AND METHODS

A thorough search in MEDLINE-PubMed, Embase and the Cochrane Central Register of controlled trials (CENTRAL) was conducted up to February 2011. Randomized clinical trials and prospective cohort studies with a follow-up of at least 3 months reporting changes on both the hard and soft tissues (height and/or width) of the alveolar process (mm or %) after tooth extraction were considered for inclusion.

RESULTS

The screening of titles and abstracts resulted in 14 publications meeting the eligibility criteria. Data from nine of these 14 studies could be grouped in the meta-analyses. Results from the meta-analyses showed a statistically significant greater ridge reduction in bone height for control groups as compared to test groups (weighted mean differences, WMD = -1.47 mm; 95% CI [-1.982, -0.953]; P < 0.001; heterogeneity: I(2) = 13.1%; χ(2) P-value = 0.314) and a significant greater reduction in bone width for control groups compared to the test groups (WMD = -1.830 mm; 95% CI [-2.947, -0.732]; P = 0.001; heterogeneity: I(2) = 0%; χ(2) P-value = 0.837). Subgroup analysis was based on the surgical protocol used for the socket preservation (flapless/flapped, barrier membrane/no membrane, primary intention healing/no primary healing) and on the measurement method utilized to evaluate morphological changes. Meta-regression analyses demonstrated a statistically significant difference favoring the flapped subgroup in terms of bone width (meta-regression; slope = 2.26; 95% IC [1.01; 3.51]; P = 0.003).

CONCLUSIONS

The potential benefit of socket preservation therapies was demonstrated resulting in significantly less vertical and horizontal contraction of the alveolar bone crest. The scientific evidence does not provide clear guidelines in regards to the type of biomaterial, or surgical procedure, although a significant positive effect of the flapped surgery was observed. There are no data available to draw conclusions on the consequences of such benefits on the long-term outcomes of implant therapy.

Secondary closure of an extraction socket using the double-membrane guided bone regeneration technique with immediate implant placement

Purpose

Immediate implantation presents challenges regarding site healing, osseointegration, and obtaining complete soft-tissue coverage of the extraction socket, especially in the posterior area. This last issue is addressed herein using the double-membrane (collagen membrane+high-density polytetrafluoroethylene [dPTFE] membrane) technique in two clinical cases of posterior immediate implant placement.

Methods

An implant was placed immediately after atraumatically extracting the maxillary posterior tooth. The gap between the coronal portion of the fixture and the adjacent bony walls was filled with allograft material. In addition, a collagen membrane (lower) and dPTFE membrane (upper) were placed in a layer-by-layer manner to enable the closure of the extraction socket without a primary flap closure, thus facilitating the preservation of keratinized mucosa. The upper dPTFE membrane was left exposed for 4 weeks, after which the membrane was gently removed using forceps without flap elevation.

Results

There was considerable plaque deposition on the outer surface of the dPTFE membrane but not on the inner surface. Moreover, scanning electron microscopy of the removed membrane revealed only a small amount of bacteria on the inner surface of the membrane. The peri-implant tissue was favorable both clinically and radiographically after a conventional dental-implant healing period.

Conclusions

Secondary closure of the extraction socket and immediate guided bone regeneration using the double-membrane technique may produce a good clinical outcome after immediate placement of a dental implant in the posterior area.

Peri-implant bone reactions to immediate implants placed at different levels in relation to crestal bone. Part II: a pilot study in dogs

PURPOSE

The aim of the present study was to evaluate bone-to-implant contact (BIC) and bone remodeling dynamics after immediate implant placement at different levels in relation to the crestal bone with two different implant designs in beagle dogs.

MATERIALS AND METHODS

The mandibular second, third and fourth premolars of six beagle dogs were extracted bilaterally and three implants were immediately placed in the hemi-arches of each dog. Randomly, three cylindrical and three tapered implants were inserted crestally (control group) or 2 mm subcrestally (test group). Both groups were treated with a minimal mucoperiosteal flap elevation approach. A gap from the buccal cortical wall to the implant was always left. Three dogs were allowed a 4-week submerged healing period and the other three an 8-week submerged healing period. The animals were sacrificed and samples were obtained. Biopsies were processed for ground sectioning. Histomorphometric analysis was carried out in order to compare BIC, de novo bone formation and bone remodeling.

RESULTS

All implants osseointegrated clinically and histologically. Healing patterns examined microscopically at 4 and 8 weeks for both groups (crestal and subcrestal) yielded similar qualitative bone findings. The total BIC mean value for the crestal group was 36.48 ± 3.4% and for the subcrestal group was 41.46 ± 4.2%. The mean percentage of newly formed BIC was greater with the cylindrical implant design (46.06 ± 1.09%) than with the tapered design (33.89 ± 1.72%). There was less bone resorption in the subcrestal group (test) than crestal group (control).

CONCLUSION

These findings suggest that apical positioning of the top of the implant does not jeopardize bone crest and peri-implant tissue remodeling. However, less resorption of the lingual crest may be expected when implants are placed 2 mm subcrestally. Moreover, higher BIC values were found in cylindrical implants placed subcrestally.