Use of Implant-Derived Minimally Invasive Sinus Floor Elevation: A Multicenter Clinical Observational Study With 12- to 65-Month Follow-Up.

The aim of this study is to evaluate the performance of implant-derived minimally invasive sinus floor elevation. A multicenter retrospective study was performed in 5 dental clinics. Patients requiring sinus augmentation for single implant placement were recorded and followed up. The dental implant used in this trial was a self-tapping endosseous dental implant that contains an internal channel to allow the introduction of liquids through the implant body into the maxillary sinus; those liquids include saline and a flowable bone grafting material. Overall, 37 implants were installed in 37 patients. The age range of the patients was 37-75 years (mean: 51.2 years). The average residual bone height prior to the procedure was 5.24 ± 1 mm. Of all cases, 25 implants replaced the maxillary first molar and 12 replaced the maxillary second premolar. All surgeries were uneventful with no apparent perforation of the sinus membrane. The mean follow-up time was 24.81 ± 13 months ranging from 12 to 65 months. All implants integrated and showed stable marginal bone level. No adverse events were recorded during the follow-up period. The presented method for transcrestal sinus floor elevation procedure can be accomplished using a specially designed dental implant. Further long-term studies are warranted to reaffirm the results of this study.

Successful rehabilitation of partial edentulous maxilla and mandible with new type of implants: molecular precision implants.

The extraction of teeth results in rapid bone resorption both vertically and horizontally in the first month. The loss of alveolar ridge reduces the chance of implant rehabilitation. Atraumatic extraction, implant placement in extraction socket, and an immediate prosthesis have been proposed as alternative therapies to maintain the volume and contours tissue and reduce time and cost of treatment. The immediate load of implants is a universally practiced procedure; nevertheless a successful procedure requires expertise in both the clinical and the reconstructive stages using a solid implant system. Excellent primary stability and high bone-implant contact are only minimal requirements for any type of implant procedure. In this paper we present a case report using a new type of implants. The new type of implants, due to its sophisticated control system of production, provides to the implantologist a safe and reliable implant, with a macromorphology designed to ensure a close contact with the surrounding bone.

Titanium alloys (AoN) and their involvement in osseointegration.

BACKGROUND: Osseointegration is essential for a long-term successful and inflammation-free dental implant. Such a result depends on osteoblastic cells growth and differentiation at the tissue-implant interface. The aim of this study was to compare two different AoN titanium layers (GR4 and GR5) to investigate which one had a greater osteoconductive power using human osteoblasts (HOb) culture at two different time-points. MATERIALS AND METHODS: The expression levels of some bone-related (ALPL, COL1A1, COL3A1, SPP1, RUNX2, and SPARC) were analyzed using real time reverse transcription-polymerase chain reaction (real time RT-PCR). RESULTS: Real-time RT-PCR data showed that after 3 days of treatment with TiA4GR, the genes up-regulated were COL3A1, ALPL, SPP1, and RUNX2. Moreover, no difference in gene expression was noticed 4 days later. On the other hand, the genes that overexpressed after 3 days of treatment with AoN5GR were ALPL, SPP1, and RUNX2. In both cases, the expression of COL1A1 and SPARC was negatively regulated. CONCLUSION: Our data showed that both titanium surfaces led to osteoblasts recruitment, maturation, and differentiation, thus promoting osseointegration at the tissue-implant interface.

Fibroblast behavior after titanium surfaces exposure.

BACKGROUND: The main requirements for a good material are its ability to promote attraction and adhesion of bone precursor cells and their proliferation and differentiation. Different biocompatible materials are currently employed as scaffold. Among these, titanium is considered a gold standard because of its biocompatibility and good corrosion resistance. MATERIALS AND METHODS: The aim of this work was to compare two different AoN titanium layers (GR4 and GR5) to investigate which one had a greater osteoconductive power using human fibroblasts (HFb) culture at two different time-points. The expression levels of some adhesion and traction-resistance related genes (COL11A1, COL2A1, COL9A1, DSP, ELN, HAS1, and TFRC) were analyzed using real time reverse transcription-polymerase chain reaction. RESULTS: After 7 days of treatment with TiA 4GR, the only two up-regulated genes were COL2A1 and DSP. After 15 days of treatment, none of genes over expressed. CONCLUSION: Our preliminary results suggest that neither AoN 4GR nor AoN 5GR are able to promote the production of protein involved in cell-cell and cell-matrix adhesion and in stress-resistance, required for a good outcome in dental implantology.

Spiral implants bearing full-arch rehabilitation: analysis of clinical outcome.

A spiral implant (SPI) is a conical internal helix implant with a variable thread design which confers the characteristic of self drilling, self tapping, and self bone condensing. The effectiveness of this type of implant has been reported in several clinical situations. However, because there are no reports that specifically focus on one of the biggest challenges in oral rehabilitation, that is, full arch rehabilitation, it was decided to perform a retrospective study. The study population was composed of 23 patients (12 women and 11 men, median age 57 years) for evaluation and implant treatment between January 2005 and June 2009. Two-hundred six spiral family implants (SFIs) were inserted with a mean postloading follow-up of 23 months. Several variables were investigated: demographic (age and gender), anatomic (maxilla and mandible, tooth site), implant (type, length, and diameter), surgical (surgeon, postextractive, flapless technique, grafts), and prosthetic (implant/crown ratio, dentition in the antagonist arch, type of loading, and computerized tomography [CT] planning) variables. Implant loss and peri-implant bone resorption were evaluated. Univariate and multivariate tests were performed. Survival and success rates were 97.1% and 82.5%, respectively. Only implant length and implant/crown ratio showed statistical significance in determining a better clinical outcome. In conclusion, SFIs are a reliable tool for the most difficult cases of oral rehabilitation. No differences were detected among implant type. Length and implant/crown ratio can influence the crestal bone resorption with better result for longer fixtures and a higher implant/crown ratio. In addition, banked bone derived from living donors can be used to restore alveolar ridge augmentation without adverse effects. Finally, flapless and CT-planned surgery did not significantly increase the clinical outcome in most complex rehabilitation.

Distance between implants has a potential impact of crestal bone resorption.

OBJECTIVES: Around dental implants exists a "biologic width" of few millimeters that have to be preserved in order to not have adverse effect on soft and hard tissues around implant. Because the minimum distance between adjacent implants has not been determined yet, we therefore, decided to perform a retrospective study on a series of spiral family implants (SFIs) to verify the minimum inter-implants' distance that has an impact on crestal bone resorption. MATERIALS AND METHODS: Fifty-nine implants were investigated with a mean follow-up of 14 months. Implant diameter was 3.75, 4.2, 5 and 6 mm in 11 (18.6%), 29 (49.2%), 17 (28.8%) and 2 (3.4%) SFIs. Implant length was shorter than 13 mm, equal to 13 mm and 16 mm in 23 (39%), 23 (39%) and 13 (22%) SFIs. Implants were inserted to replace 13 incisors (22%), 7 cuspids (11.9%), 30 premolars (50.8%) and 9 molars (15.3%). Twenty-seven fixtures were inserted in post-extractive sockets and the remaining 32 in healed bone; 36 (61%) were immediately loaded. In addition to the above mentioned implant-related factors, several host- and surgery-factors were investigated. Independent samples T-test, univariate and multivariate analysis were used to detect those variables associated with the clinical outcome. RESULTS: Data were evaluated with a two steps statistical analysis (i.e. univariate and multivariate) after having grouped implants in two series: those with an implant-implant distance less of 1.8 mm and those with an implant-implants distance greater than 1.8 mm. In univariate analysis, post-extractive implants and number of prosthetic units were statistically significant. In multivariate analysis, only post-extractive implants have a significant adverse effect on crestal bone resorption. CONCLUSIONS: Adjacent implants inserted with a distance lower and higher than 1.8 mm have difference in crestal bone resorption but this difference is not statistically significant in a short period follow up. This could due to the specific implant used that has a reverse conical neck. No statistical difference was detected between implant subtypes. Post-extractive implant insertion is the major determinant in terms of peri-implant bone resorption in a short period follow-up.

Flapless surgery and immediately loaded implants: a retrospective comparison between implantation with and without computer-assisted planned surgical stent.

OBJECTIVES: Computer planned flapless surgery and immediate loading are the most recent topics in implantology. One new computer-planned implant system uses a three-dimensional parallelometer able to transfer the implant position from the virtual project to the master model. The aim of this study was to verify if the new medical device gives an advantage in term of implant failures and/or crestal bone remodeling. MATERIAL AND METHODS: A retrospective study was planned to analyze a series of 193 immediately loaded fixtures inserted by means of flapless surgery. From those sixty six implants were inserted with computer planning whereas 127 were inserted "free-hand". Several variables related to patient, anatomy, implant, surgery and prosthesis were investigated. To detect the clinical outcome implant' failure and peri-implant bone resorption were considered. Kaplan-Meier algorithm and Cox regression were then performed to detect those variables statistically associated with the clinical outcome. RESULTS: Implant length and diameter ranged from 10 to 16 mm and from 3.75 to 6.0 mm, respectively. Implants were inserted to replace 46 incisors, 30 cuspids, 75 premolars and 42 molars. The mean follow-up period was 15 months. Seven implants were lost (survival rate 96.4%) but no studied variable has a statistical impact on failures. On the contrary, implants inserted in sites with completed bone healing, wide diameter fixtures and implants inserted in totally edentulous jaw had a significantly lower crestal bone resorption. The other variables (age, gender, upper/lower jaws, tooth site, implant' type and length, number of prosthetic units antagonist condition) did not have impact on crestal remodeling. CONCLUSION: Computer-planned and cast model transferred implantology is a reliable technology that provides a slightly higher clinical outcome than "free hand" technique at least in healed sites, wider implants and totally edentulous jaws.

Randomised study for the 1-year crestal bone maintenance around modified diameter implants with different loading protocols: a radiographic evaluation.

This study evaluated by standardised digitised periapical radiography the crestal bone maintenance around modified diameter internal hex implants with variable thread design and narrow neck loaded with different procedures. Forty implants were placed in 25 patients. Twenty implants were conventionally loaded, 20 ones immediately loaded. Radiographs were taken with a customised bite record and processed with software. Measurements of bone from the fixture-abutment junction to mesial and distal marginal bone levels were made. Student's t test statistical analysis was adopted. Baseline data were variable; at 1-year follow-up, there were no significant differences for marginal bone loss between immediately and conventionally loaded maxillary implants (p = 0.1031), whilst there were slight significant differences between immediately and conventionally loaded implants in the mandible (p = 0.0141). Crestal bone maintenance around conventionally and immediately loaded modified diameter implants was similar, with slight significant differences in mandible where a lower marginal bone loss was observed.

Bone platform switching: a retrospective study on the slope of reverse conical neck.

OBJECTIVE: Bone platform switching results in an inward bone ring in the coronal part of an implant that is in continuity with the alveolar bone crest. Bone platform switching is achieved by using a dental implant with a reverse conical neck (RCN). A retrospective study was performed to determine the impact of RCN on crestal bone remodeling (CBR). METHOD AND MATERIALS: A series of 191 implants with the same morphology, but three slopes of RCN, were evaluated. Lost implants and CBR around implants still in place at the end of the follow-up were considered to investigate those variables potentially associated with the clinical outcome. Radiographic examinations were performed for each implant before surgery and at the end of the follow-up to detect the degree of CBR. Time-dependent cutoff values were used to select implants with higher CBR. These implants were considered unsuccessful. The Kaplan-Meier algorithm was applied to detect those variables potentially associated with the clinical outcome (ie, lost implants or implants with higher CBR). RESULTS: Only 5 of 191 implants were lost (survival rate 97.4%). No statistical differences were detected among the studied variables by using lost implants. CONCLUSIONS: Although no statistical differences were detected among the three types of implants, the data seem to indicate a correlation between CBR and the slope of the RCN, with a better outcome for implants with a more angulated RCN.

Platform switching and bone platform switching.

Bone platform switching involves an inward bone ring in the coronal part of the implant that is in continuity with the alveolar bone crest. Bone platform switching is obtained by using a dental fixture with a reverse conical neck. A retrospective study was performed to evaluate the effectiveness of conventional vs reverse conical neck implants. In the period between May 2004 and November 2007, 86 patients (55 females and 31 males; median age, 53 years) were operated and 234 implants were inserted: 40 and 194 were conventional vs reverse conical neck implants, respectively. Kaplan-Meier algorithm and Cox regression were used to detect those variables associated with the clinical outcome. No differences in survival and success rates were detected between conventional vs reverse conical neck implants alone or in combination with any of the studied variables. Although bone platform switching leads to several advantages, no statistical difference in alveolar crest resorption is detected in comparison with reverse conical neck implants. We suppose that the proximity of the implant abutment junction to the alveolar crestal bone gives no protection against the microflora contained in the micrograph. Additional studies on larger series and a combination of platform switching and bone platform switching could lead to improved clinical outcomes.

Comparison between implants inserted into piezo split and unsplit alveolar crests.

PURPOSE: Piezoelectric surgery (PES) uses a modulated ultrasonic frequency that permits highly precise and safe hard tissue cutting. A retrospective study on a series of spiral family implants inserted with or without PES split crest was performed to verify if implants inserted into crests split using PES have a comparable outcome to those inserted into unsplit bone. MATERIAL AND METHODS: In the period from May 2004 to November 2007, 86 patients (55 women and 31 men, median age 53 yrs) were operated on and 234 spiral family implants were inserted. Among these, 21 were inserted into PES split crest. Mean follow-up was 13 months (3 to 35 months). The Kaplan-Meier algorithm was used to compare the 2 groups in survival and clinical success (ie, decreased bone resorption around implant neck). RESULTS: Only 9 of 234 implants were lost (ie, survival rate 96.2%), all of which belonged to the unsplit group but no statistical difference was demonstrated. To detect if PES split crest produces a better clinical outcome in comparison with fixtures inserted into unsplit alveolar ridges, crestal bone loss was compared in the remaining loaded implants (234--9 lost--5 not prosthetized = 220). No statistical significant difference was detected by comparing implants inserted into PES split crests with untreated alveolar ridges, although a better trend was visible for fixtures inserted into PES split crests. CONCLUSION: PES split crests provide several advantages and clinical outcomes that are not worse in terms of bone remodeling, if compared with standard procedures.

The clinical outcomes of 234 spiral family implants.

AIM: Spiral family implants (SFIs) are a new type of implant fixture with a conical internal helix and a variable thread design. The aim of this retrospective study was to evaluate the clinical outcomes of a series of SFIs. METHODS AND MATERIALS: A total of 234 SFIs were placed in 86 patients (55 females and 31 males, median age 53 years) during the period between May 2004 and November 2007. The mean follow-up was 13 months. Several host, surgery, and implant-related factors were investigated, and the Kaplan Meier algorithm and the Cox regression were used to detect variables associated with the clinical outcome. RESULTS: Only nine out of 234 implants were lost (i.e., survival rate (SVR) of 96.2%) and no differences were detected among the studied variables. CONCLUSION: SFIs have a high SVR similar to those reported in previous studies on different implant types. CLINICAL SIGNIFICANCE: SFIs demonstrated a very high primary stability which offers the potential for use of a specific implant device for immediate loading. However, additional studies are necessary to verify their outcome on the medium/long period.

Comparison between implants inserted with and without computer planning and custom model coordination.

PURPOSE: In the last decade, several systems for computer-planned implantology have been reported. Among them is a system that uses software and a three-dimensional parallelometer able to transfer the implant position from the virtual project to the master model. To verify the effectiveness of this system, a retrospective comparative study has been planned. MATERIALS AND METHODS: A series of 300 implants were analyzed. Sixty-six were inserted with computer planning. Several variables related to patient, anatomic site, implant, and surgery were investigated. Implants' failure and peri-implant bone resorption were considered as predictors of clinical outcome. Kaplan-Meier method and Cox regression analysis were then performed to detect those variables statistically associated with the clinical outcome. RESULTS: Implant length and diameter ranged from 10 to 16 mm and from 3.75 to 6.0 mm, respectively. Implants were inserted to replace 66 incisors, 39 canines, 116 premolars, and 79 molars. Mean follow-up was 14 months. Nine implants were lost (survival rate, 97%), but no differences were detected among the studied variables. On the contrary, lower crestal bone resorption was detected for implants inserted in healed bone and in anterior jaws. CONCLUSIONS: Computer-planned and cast model-transferred implantology give good clinical results in survival and success rate. It is a useful technology that should be used in most difficult cases such as totally edentulous patients and reduced crestal bone volume.

Spiral family implants inserted in postextraction bone sites.

PURPOSE: In the last 2 decades, several investigators have reported immediate placement of dental implants into extraction sockets achieving excellent results with a 2-stage surgical procedure. Recently, immediate loading has become an emerging technique as it has been documented to be a successful and a time saving procedure. As regard, few reports are available for the possibility of immediate/early loading of implants placed in fresh extraction sockets. In addition, they are based on limited series with short follow-up. Thus, we decided to perform a retrospective study on a series of postextractive spiral family implants (SFIs). MATERIALS AND METHODS: In the period May 2004 to November 2007, 133 SFIs were inserted in fresh extraction sockets. The mean follow-up was 12 months. Several host-, surgery-, and implant-related factors were investigated and Kaplan-Meier algorithm and Cox regression were used to detect those variables associated with the clinical outcome. RESULTS: Because only 7 of 133 implants were lost (i.e., survival rate, 94.7%) and no statistical differences were detected among the studied variables, no, or reduced, marginal bone loss was considered as an indicator of success rate to evaluate the effect of several host-, surgery-, and implants-related factors. Also, in this case no variable has impact on clinical outcome. CONCLUSION: It was demonstrated that postextractive SFIs have a high survival and success rate that are similar to those reported in previous studies of 2-stage procedures or in immediate loading implants inserted in healed bone.

3D finite element analysis to detect stress distribution: spiral family implants.

AIM: Spiral family implants are a root-form fixtures with increasing thickness of tread. This characteristic gives a self-tapping and self-condensing bone properties to implants. To study spiral family implant inserted in different bone quality and connected with abutments of different angulations a Finite Element Analysis (FEA) was performed. Once drawn the systems that were object of the study by CAD (Computer Aided Design), the FEA discretized solids composing the system in many infinitesimal little elementary solids defined finite elements. This lead to a mesh formation where the single finite elements were connected among them by nodes. For the 3 units bone-implant-abutments several thousand of tetrahedral elements having 10 parabolic nodes were employed. MATERIALS AND METHODS: The biomechanical behaviour of 4.2 mm × 13 mm dental implants, connecting screw, straight and 15° and 25° angulated abutment subjected to static loads, in contact with high and poor bone quality was evaluated by FEA. A double system was analyzed: a) FY strength acting along Y axis and having 200 N intensity; b) FY and FZ couple of strengths applied along Y and Z directions and having respectively 200N and 140N intensity. The materials were considered as homogeneous, linear and isotropic. Then the FEA simulation was performed hypothesizing a linearity between loads and deformations. RESULTS: The lowest stress value was found in the system composed by implants and straight abutments loaded with a vertical strength, while the highest stress value were found in implants and 15° angulated abutment loaded with a angulated strength. In addition, the lower is the bone quality (i.e. D4) the higher is the distribution of the stress within the bone. CONCLUSION: Spiral family implants can be used successfully in low bone quality but a straight force is recommended.

A new device for impression transfer for non-parallel endosseus implants.

The three-dimensional orientation of dental implant is transferred to a model by means of transfer device and impression material. If more than one implant is inserted and fixtures are not perfectly parallel, the impression may become distorted when removed from the mouth. In this case, a transfer that can be disengaged from the internal implant-abutment connection and removed together with the tray could be useful. An impression transfer device composed of a proper transfer, an inner hexagon and a central screw is described. When the central screw and the hexagon are removed, the proper transfer is free to move horizontally and the tray can be removed from the mouth without distortion of the impression material.

Three dimensional finite element analysis to detect stress distribution in spiral implants and surrounding bone.

BACKGROUND: The aim of research was to study spiral family implant by finite element analysis (FEA) inserted in different bone qualities connected with abutments of different angulations. METHODS: The biomechanical behaviour of 4.2 × 13 mm dental implants, connecting screw, straight and 15° and 25° angulated abutments subjected to static loads, in contact with high and poor bone qualities was evaluated by FEA. RESULTS: The lowest stress value was found in the system composed by implants and straight abut-ments loaded with a vertical force, while the highest stress value was found in implants with 15° angulated abutment loaded with an angulated force. In addition, we found the lower the bone quality, the higher the distribution of the stress within the bone. CONCLUSION: Spiral family implants can be used successfully in low bone quality but applying a straight force is recommended.