10-year follow-up of immediately loaded implants with TiUnite porous anodized surface

BACKGROUND

The immediate loading of implants with a porous anodized surface is a well-described technique. Few data are however available on the long-term outcomes.

PURPOSE

The aim of this prospective study was to assess the 10-year performance of TiUnite implants supporting fixed prostheses placed with an immediate loading approach in both postextractive and healed sites.

MATERIALS AND METHODS

All patients received a fixed provisional restoration supported by immediately loaded parallel design, self-tapping implants with a porous anodized TiUnite surface, and an external-hexagonal connection. Both healed and postextractive cases were included. Success and survival rate for restorations and implants, changes in marginal peri-implant bone level, probing depth measurements, biological or technical complications, and any other adverse event were recorded at yearly follow-up up to 10 years after surgery.

RESULTS

A total of 210 implants fulfilled the inclusion criteria and were consecutively placed in 59 patients. Forty-seven (22.38%) implants were lost because of the recalled patient refused to attend the planned 10-year follow-up. Five over 210 (2.38%) implants were lost. At the final follow-up, the accumulated mean marginal bone loss and probing depth were, respectively, 1.93 mm (SD 0.40) and 2.54 mm (SD 0.44) for the implants placed in healed sites (n = 84); 1.98 mm (SD 0.37) and 2.63 mm (SD 0.39) for the implants placed in postextractive sites (n = 74). The restorations examined achieved a cumulative 65.26% success rate and 97.96% survival rate. The implants placed in healed and postextractive sites, respectively, achieved a 98.05% and a 96.52% cumulative survival rate.

CONCLUSIONS

Positive results in terms of bone maintenance in the long-term perspective are to be expected using immediately loaded implants with a TiUnite porous anodized surface in both postextractive and healed sites when adequate levels of oral hygiene are kept.

Fractal analysis: a novel method to assess roughness organization of implant surface topography

Surface roughness is important for implant osseointegration. It has mostly been assessed by amplitude and height descriptors. Fractal analysis is derived from fractal geometry and is used to describe the organization of objects found in nature, quantifying their shape complexity with a value. Fractal dimension (Df?) is an index of the space-filling properties of an object and can be used as a parameter that describes the organization of surface roughness. The greater the Df value, the more chaotic the surface topography. The aim of this study was to assess the Df of implants with three different surface topographies to evaluate whether a novel method to measure roughness of implant surface topography could be developed. Forty-five disk-shaped samples (10 x 2 mm) with three different surface topographies were analyzed by scanning electron microscopy: group A, machined surface; group B, sandblasted and acid-etched surface; and group C, sandblasted, acid-etched, and neutralized surface. Images at 20,000x and 50,000x magnification were processed for quantitative analysis of Df using the box-counting method. Df values were correlated to the image magnification. At 20,000x magnification, Df for groups A, B, and C was 1.81, 1.67, and 1.59, respectively. At 50,000x magnification, Df was lower for all examined groups; more specifically, Df was 1.77, 1.59, and 1.42 for groups A, B, and C, respectively. Statistically significant differences were found between groups A and C at both magnifications. Df is used widely and successfully as a measurement to characterize anatomical structures and physiologic and pathologic processes. Df not only provides an index of roughness size values, but also a measure of roughness spatial organization; therefore, it could be a promising method to differentiate between rough surfaces capable of supporting osseointegration.

Development of a new implant primary stability parameter: insertion torque revisited

PURPOSE

The aims of the study are to introduce a new parameter to measure primary stability and to evaluate the possible correlations between this parameter and bone density, initial bone-to-implant contact (IBIC), Resonance Frequency Analysis (RFA), and peak insertion torque (IT).

MATERIAL AND METHODS

The study was performed on three different types of fresh humid bovine bone: type I, type II, and type III. A total of 90 XiVE implants (30 per bone type) were used; implant insertion was performed with a calibrated maximum torque of 70 Ncm at predetermined 30 rpm. The IT data were recorded and exported as a curve; using a trapezoidal integration technique, the area underlying the curve was calculated: this area represents the variable torque work (VTW). Furthermore, peak IT and RFA were recorded; finally IBIC was calculated from histological specimens.

RESULTS

Spearman correlation analysis of the entire sample reveals that VTW presents a significant (p < .01) positive correlation with bone density; a significant (p < .05) positive correlation with IBIC, and a significant (p < .01) positive correlation with all the other primary stability parameters. Spearman correlation analysis of the three different groups show that VTW presents a significant positive correlation with IT in all three types of bone; on the other hand, VTW shows a negative not significant correlation with RFA in bone I, a positive significant correlation in bone II, and a positive not significant correlation in bone III. Furthermore, VTW shows a negative significant correlation with IBIC in bone I and a positive significant correlation in bone II and III.

CONCLUSIONS

Within the limitations of an in vitro study, the VTW seems to be a promising parameter to measure implant primary stability.

Reconstruction of an atrophied posterior mandible with the inlay technique and inorganic bovine bone block: a case report

A 53-year-old woman underwent bilateral reconstruction of her severely atrophic posterior mandible using inlay inorganic bovine bone block grafting. Four months later, a bone specimen was taken for histologic evaluation and eight dental implants were placed. These implants were loaded with a provisional prosthesis after another 4 months. When the definitive prosthesis was inserted 8 months postsurgery, all implants were osseointegrated. Histologic analysis showed that the grafted bone was lined with newly formed bone. The results indicate that inorganic bovine bone blocks might serve as an alternative to autogenous grafting for posterior mandibular augmentation using the inlay technique.

Immediate loading of the edentulous maxilla with a definitive restoration supported by an intraorally welded titanium bar and tilted implants

PURPOSE

The aim of this prospective study was to evaluate the concept of intraoral welding as a suitable technique for the fabrication of a restoration for the edentulous atrophic maxilla on the day of placement of axial and tilted implants.

MATERIALS AND METHODS

Thirty patients received three axial and four tilted implants in the edentulous maxilla. Immediately after implant placement, definitive abutments were connected to the implants and then a titanium bar was welded to them using an intraoral welding unit. This framework was used as a support for the definitive restoration, which was attached on the day of implant placement. Mean marginal bone loss and radiographically detectable alteration of the welded framework were assessed using periapical radiographs immediately after surgery and at 6, 12, 24, and 36 months after placement.

RESULTS

Sixteen men and 14 women with an average age of 58.1 years (SD 13.6) were consecutively treated with 210 immediately loaded implants. No fractures or radiographically detectable alterations of the welded frameworks were evident. A 100% prosthetic success rate was seen at 36 months. Three (1.4%) implants had serious biologic complications, resulting in success rates of 97.8% for axial implants and 99.2% for tilted implants. The accumulated mean marginal bone loss was 0.92 mm (SD 0.75; n = 90) for axial implants and 1.03 mm (SD 0.69; n = 120) for tilted implants. The average pocket probing depths were 1.87 mm (SD 0.98; n = 90) for the axial implants and 1.95 mm (SD 0.81; n = 120) for the tilted implants.

CONCLUSIONS

It is possible on the day of implant placement surgery to successfully rehabilitate the edentulous atrophic maxilla with a fixed, definitive restoration supported by an intraorally welded titanium framework attached to axial and tilted implants.

Primary stability determination by means of insertion torque and RFA in a sample of 4,135 implants

OBJECTIVES

The aims of the present study are to evaluate the primary stability of a sample of 4,135 implants and to investigate the correlations between primary stability and mechanical characteristic of the implant and bone density at insertion time.

MATERIAL AND METHODS

The study was conducted from March 2002 to January 2009 at a private practice in Bologna (Italy). Patients were eligible for the study if they needed the insertion of single or multiple implants. Bone density, length, and diameter of each implant were recorded. During surgery for each implant, peak insertion torque (IT) was recorded; the resonance frequency analysis (RFA) values were also collected. Finally, it was recorded whether an implant was lost or removed at an early stage (within 6months from insertion surgery).

RESULTS

A total of 1,045 consecutive patients were included in the study. A total of 4,135 of implants were inserted. The sample presented 1,184 implants inserted in a postextractive site. The mean peak IT was 34.82±19.36. The mean RFA was 71.57±10.63 implant stability quotient. Spearman correlation analysis shows the presence of a weak positive correlation between IT and RFA. The statistical analysis shows a relevant dependency between IT and bone quality and a very weak dependency between RFA and bone quality. Again, the statistical analysis shows a quite weak correlation between length or diameter and IT, but it shows a relevant correlation between length and RFA. Postextractive implants presented a higher mean IT and a lower RFA compared with implants inserted in healed sites. Twenty-eight (0.7%) implants were considered to have failed and removed within 6months.

CONCLUSIONS

The results show that the implants studied obtain a good primary stability with a standard protocol. The IT and RFA appear as two independent features of primary stability. Data show that only IT is influenced by bone density as well as only RFA is correlated to the length of implants used. Finally, it is possible to obtain a good primary stability also in postextractive sites.

Immediate definitive rehabilitation of the edentulous patient using an intraorally welded titanium framework: a 3-year prospective study

OBJECTIVE

The aim of this prospective study was to evaluate the concept of intraoral welding as a suitable technique for the placement of a final restoration in the edentulous patient on the same day as surgery.

METHOD AND MATERIALS

Any patient with a completely edentulous arch who was considered eligible received a fixed restoration supported by an intraorally welded titanium bar. Definitive abutments were connected to the implants and then welded to a titanium bar using an intraoral welding unit. This framework was used to support the definitive acrylic restoration, which was fitted on the same day as implant placement. Restoration and implant success, mean marginal bone loss, pocket probing depth, and bleeding on probing were assessed over a 36-month follow-up period.

RESULTS

Twenty-six patients with an edentulous maxilla and 34 patients with an edentulous mandible, with a mean age of 57.1 years (SD = 17.9, n = 60), were consecutively treated with 324 immediately loaded implants. No fractures or radiographically detectable alteration of the welded framework was evident. A total of 321 (99.1%) implants osseointegrated and were clinically stable at the 6-month follow-up. At the 36-month follow-up, the accumulated mean marginal bone loss was, respectively, 0.967 mm (SD = 0.361) for the maxillary cases and 1.016 mm (SD = 0.413) for the mandibular cases.

CONCLUSIONS

It is possible on the same day of surgery to successfully rehabilitate the edentulous patient with a fixed definitive prosthesis supported by an intraorally welded titanium framework.

Determination of primary stability: a comparison of the surgeon's perception and objective measurements

PURPOSE

To evaluate the difference between the dental surgeon's perception of implant stability and the actual insertion torque and actual values obtained through resonance frequency analysis (RFA) during implant insertion surgery.

MATERIALS AND METHODS

One hundred fifty-two patients who needed one or more dental implants were selected. A total of 514 Xive implants was inserted. For all 514 implants, after insertion, the oral surgeon was asked to indicate the probable RFA values (implant stability quotient [ISQ]). For 483 implants, the surgeon was also asked to indicate the probable insertion torque values (N/cm). The actual values were then measured. The RFA and insertion torque values were grouped into low, medium, and high groups.

RESULTS

The mean perceived RFA was 72.2 +/- 9.8 ISQ. The mean actual RFA was 73.5 +/- 10.2 ISQ. This difference was statistically significant (P = .01). The mean perceived insertion torque was 39.1 +/- 20.1 Ncm. The mean actual insertion torque was 39.9 +/- 20.7 Ncm. The mean difference between actual and perceived ISQ values was -1 +/- 14.9, with a range from -60 to 59; the mean difference between actual and perceived insertion torque values was -1.3 +/- 9.9, with a range from -38 to 45.

CONCLUSIONS

Xive implants obtained good primary stability in many different clinical situations with a standard protocol. Primary stability is generally underestimated, especially in the presence of low or medium ISQ and torque values. The accuracy of primary stability prediction is not good enough to prevent mistakes when using an immediate loading technique; therefore, a more systematic use of objective measurements is encouraged.

A comparison between immediate loading and immediate restoration in cases of partial posterior mandibular edentulism: a 3-year randomized clinical trial

OBJECTIVE

The aim of this study was to compare the survival rate, the bone loss and soft-tissue healing patterns of immediately loaded and immediately restored implants in cases of partial posterior mandibular edentulism.

MATERIAL AND METHODS

Fifty patients with partial posterior mandibular edentulism were randomly selected for two treatments: 25 were included in the immediate loading group (test) and 25 in the immediate restoration group (control). All implants were placed in healed sites with a torque of >25 N cm. The temporary prosthesis of the immediate restoration group was placed so as to avoid occlusal contact in centric and lateral excursions. Both groups received fully occluding final restorations 6 months after surgery. Mean marginal bone loss was assessed at 6-, 12-, 24- and 36-month follow-up examinations by a blinded examiner.

RESULTS

A total of 100 implants were placed in the period between February 2004 and October 2006, of which 42 (42%) were for men and 58 (58%) for women. Five and 7 weeks after surgery, mobility of one implant was assessed in one (4%) patient in the test group and one (4%) patient in the control group, respectively. At the 36-month follow-up, the accumulated mean marginal bone loss was 0.987 mm (SD=0.375) for the immediate restoration group (n=48) and 0.947 mm (SD=0.323) for the immediate loading group (n=48). There was no statistically significant difference (P>0.05) for the tested outcome measures between the two procedures.

CONCLUSIONS

This study was unable to detect any statistically significant difference in the survival rate, bone loss and soft tissue healing patterns between the immediately loaded and the immediately restored implants in cases of partial posterior mandibular edentulism. The immediate temporary rehabilitation of the partially edentulous posterior mandible is a predictable procedure using both procedures.

Mineralized bone-implant contact and implant stability quotient in 16 human implants retrieved after early healing periods: a histologic and histomorphometric evaluation

PURPOSE

Resonance frequency analysis (RFA) is a quantitative method for the measurement of implant stability. Information about the significance of RFA measurements and the relationship between RFA values and implant osseointegration, success, or failure is important from a clinical point of view. In a previous study the authors observed a strong correlation between RFA values and mineralized bone-implant contact percentage in implants retrieved after 6 months. The aim of the present histologic and histomorphometric study was to determine whether the same correlation existed at earlier time points, specifically in implants retrieved after 4 or 8 weeks.

MATERIALS AND METHODS

Sixteen implants, all with a sandblasted and acid-etched surface, were evaluated in the present study. The implants were retrieved for different reasons after 4 or 8 weeks of healing with a 5-mm trephine bur and immersed in 10% buffered formalin to be processed for histology.

RESULTS

A statistically insignificant correlation was detected between RFA values and mineralized bone-implant contact percentage (P = or < .5502) using the Friedman and Spearman tests.

CONCLUSION

RFA should reflect the bone anchorage of the implant; however, the relationship between bone structure and RFA is not fully understood.

Bone formation around one-stage implants with a modified sandblasted and acid-etched surface: human histologic results at 4 weeks

The aim of this histologic and histomorphometric study was to evaluate the peri-implant bone formation around one-stage surface-modified implants that were retrieved after a healing period of 4 weeks in humans. Three patients with mandibular partial edentulism participated in the study. An implant was inserted in the posterior mandible of each patient. All implants were retrieved after a 4-week healing period. Before retrieval, all the implants were clinically osseointegrated and immobile. Around all implants, mature compact preexisting bone, lined by newly formed strongly stained bone, was found. The bone-implant contact percentages were 52.0% +/- 2.5%, 61.0% +/- 2.9%, and 42.0% +/- 6.9%, respectively, in the three included patients. These high bone-implant contact percentages observed in an early phase of healing are probably related to the microporous structure of both surfaces and their high hydrophilicity.

Bone formation around immediately loaded and submerged dental implants with a modified sandblasted and acid-etched surface after 4 and 8 weeks: a human histologic and histomorphometric analysis

PURPOSE

A high clinical and radiographic level of osseointegration has been reported for early and immediately loaded (IL) implants. The aim of this study was to analyze, histologically and histomorphometrically, the bone-titanium interface of IL and submerged titanium implants that were retrieved at 4 and 8 weeks after placement.

MATERIALS AND METHODS

Four patients underwent rehabilitation of the posterior mandible with fixed prostheses, and an additional implant was inserted distally in the mandible. In two patients, the additional implants were put into nonfunctional immediate loading with a fixed provisional prosthesis on the same day of the implant surgery, whereas in the other two patients, the implants were left submerged. The implant stability quotients at implant insertion were 70 and 67 for the submerged implants and 69 and 77 for the IL implants. Before retrieval, the IL implants were clinically osseointegrated and were not mobile. After 4 and 8 weeks, the four implants (two IL and two submerged) were retrieved with a 5-mm trephine and processed for histologic examination.

RESULTS

After 4 weeks, the IL implant showed a bone-implant contact percentage (BIC) of 65.6%, while the BIC for the submerged implant was 54.7%. After 8 weeks, the BIC was 76.2% for the IL implant, while for the submerged implant it was 62.3%.

CONCLUSIONS

Very high BICs were present after 4 and 8 weeks around both submerged and IL implants, with the latter showing a higher quantity of bone. IL did not impede bone formation in the early healing periods.

Early bone formation around immediately restored implants with and without occlusal contact: a human histologic and histomorphometric evaluation. Case report

Human biopsy of immediately loaded implants is the most definitive means to determine the occurrence of osseointegration. This case report discusses the histologic and histomorphometric analysis of the bone-titanium interface in immediately restored implants with and without occlusal contact, retrieved after a healing period of 5 weeks. The two implants had been inserted in the posterior mandible; both were freestanding. One implant had been put into functional loading (in occlusal contact) with a fixed provisional prosthesis on the day of implant surgery (implant A), whereas the other implant was restored without occlusal contact (implant B). Both implants were retrieved with a 5-mm trephine after 5 weeks. Before retrieval, both implants appeared to be clinically osseointegrated, and no mobility was present. Both implants were surrounded by newly formed bone lamellae. In both implants about 0.5 to 1 mm of pre-existing and newly formed bone was found coronal to the implant shoulder, with no resorption of the pre-existing coronal bone. The bone-implant contact percentage in implant A was 51.2% +/- 4.5%, whereas in implant B it was 55.1% +/- 2.3%. Within the limitations of this study, the histologic findings indicated that no differences were found in the histologic response around immediately restored implants with and without occlusal contact.

Is insertion torque correlated to bone-implant contact percentage in the early healing period? A histological and histomorphometrical evaluation of 17 human-retrieved dental implants

OBJECTIVE

A precise and scientifically established method for the evaluation of the bone quality/primary stability is the measure of the insertion torque (IT). The aim of this study was a comparison between the IT values and the bone-implant contact percentage (BIC) of human implants retrieved after a 4/8-week healing period.

MATERIALS

Seventeen implants, all with a sandblasted and acid-etched surface, were evaluated in the present study.

METHODS

The implants had been retrieved for different causes, after 4/8 weeks, with a 5 mm trephine bur, and immersed in 10% buffered formalin to be processed for histology.

RESULTS

A not statistically significant correlation was found between IT and BIC (P<or=0.892).

CONCLUSIONS

In the present study on human-retrieved implants, no statistically significant correlation was found between the IT values and BIC. These results could be due to a lack of relationship between bone structure and IT, or to the fact that primary stability may not only be influenced by bone volumetrical density and/or bone trabecular connectivity but also by the thickness and density of the cortical layer. Moreover, the present knowledge of the bone microstructure is not enough to explain the relationship of bone quality and primary implant stability.