<clinical_study>
  <!-- This xml conforms to an XML Schema at:
    https://clinicaltrials.gov/ct2/html/images/info/public.xsd -->
  <required_header>
    <download_date>ClinicalTrials.gov processed this data on September 20, 2023</download_date>
    <link_text>Link to the current ClinicalTrials.gov record.</link_text>
    <url>https://clinicaltrials.gov/ct2/show/NCT03232372</url>
  </required_header>
  <id_info>
    <org_study_id>HUB</org_study_id>
    <nct_id>NCT03232372</nct_id>
  </id_info>
  <brief_title>The Marginal Bone Loss in Dental Implants</brief_title>
  <acronym>BL-Implants</acronym>
  <official_title>The Marginal Bone Loss in Implants of External Connection Versus Internal Connection and Submerged Implants Versus Non-submerged Implants</official_title>
  <sponsors>
    <lead_sponsor>
      <agency>Hospital Universitari de Bellvitge</agency>
      <agency_class>Other</agency_class>
    </lead_sponsor>
  </sponsors>
  <source>Hospital Universitari de Bellvitge</source>
  <oversight_info>
    <has_dmc>Yes</has_dmc>
    <is_fda_regulated_drug>No</is_fda_regulated_drug>
    <is_fda_regulated_device>No</is_fda_regulated_device>
  </oversight_info>
  <brief_summary>
    <textblock>
      When an implant is placed, it is assumed that there will be a loss of bone in the more&#xD;
      coronal area around it. The placement of the implant in relation to bone level, either&#xD;
      crestal or subcrestal and the type of connection chosen, either external connection or&#xD;
      internal connection, have been related as one of the factors that caused this loss. The&#xD;
      preservation of the peri-implant bone influences the shape and contour of the underlying soft&#xD;
      tissues, which are important for the aesthetic result of the treatment and for the success of&#xD;
      the same.&#xD;
&#xD;
      Hypothesis: The hypothesis is that there are no differences between the external and internal&#xD;
      connection with regard to marginal bone loss. In implants placed at the crestal and&#xD;
      subcrestal level, the hypothesis is that there is greater marginal bone loss in implants&#xD;
      placed at the subcrestal level.&#xD;
&#xD;
      Objectives: Main: To evaluate the marginal bone loss around implants of internal connection&#xD;
      and external connection. Secondary: To compare the loss of bone in implants of internal&#xD;
      connection placed at crestal and subcrestal level. To evaluate intra and post-operative&#xD;
      complications.&#xD;
&#xD;
      Material and methods: A prospective and randomized radiological study will be performed. 150&#xD;
      implants will be placed in patients who must present partial edentulism and require the&#xD;
      replacement of at least 2 crowns on implants in the same jaw. In a randomized manner,&#xD;
      implants of external connection and internal connection will be placed. Other features such&#xD;
      as surface treatment type of the implant will be similar in both types of implants to reduce&#xD;
      bias.&#xD;
&#xD;
      With this study the investigators will try to define if there is a procedure in when to the&#xD;
      connection of the implant and the location of this, that is more beneficial with respect to&#xD;
      the preservation of bone.&#xD;
    </textblock>
  </brief_summary>
  <detailed_description>
    <textblock>
      Implant dentistry has undergone major development and expansion since the nineteen sixties,&#xD;
      when Dr. Branemark (Sweden) introduced the concept of osseointegration. The use of implants&#xD;
      to replace missing teeth and restore function has presented a high success rate and long-term&#xD;
      survival. For this reason rehabilitation by means of implants has become standard and well&#xD;
      accepted by patients, who increasingly demand treatments offering greater comfort and&#xD;
      aesthetics. Implant-based treatments must fulfill a range of physiological, functional and&#xD;
      aesthetic criteria before they can be considered successful. These include osseointegration&#xD;
      stability and duration, absence of pathological processes, and aesthetics that satisfy the&#xD;
      patient.&#xD;
&#xD;
      There are diverse types of implants and corresponding systems that connect the implant to the&#xD;
      prosthesis. Implant connections fall into two main groups: External and Internal Connection.&#xD;
&#xD;
      When an implant is placed, it is estimated that there will be bone loss around this during&#xD;
      the first year, both horizontally and vertically. Actually is considered successful if the&#xD;
      loss of crestal bone around the implant is less than 1.5mm during the first year and less&#xD;
      than 0.2 annually in the next. This bone loss continues to occur despite the new designs of&#xD;
      implants that try to stop it. The preservation of the peri-implant bone is an important&#xD;
      factor for the success of the same. The quantity and quality influence the shape and contour&#xD;
      of the overlying soft tissues, which are important for the aesthetic result of the treatment.&#xD;
      The hypothesis is that there are no differences between the external and internal connection&#xD;
      with regard to marginal bone loss. In implants placed at the crestal and subcrestal level,&#xD;
      the hypothesis is that more marginal bone is loss in implants placed at the subcrestal level&#xD;
      design.&#xD;
&#xD;
      A prospective randomized controlled, split-mouth clinical trial with a sample size of 50&#xD;
      implants per arm is proposed.&#xD;
&#xD;
      Population of the study Patients attended in HOUB (Hospital Odontológico Universitario de&#xD;
      Bellvitge. Master of Medicine Surgery and Implantology and Master of Dentistry in Oncology&#xD;
      and Immunocompromised Patients).&#xD;
&#xD;
      Inclusion criteria Patients of general age who present partial edentulism in the mandible and&#xD;
      / or maxilla and require the replacement of at least 2 teeth by implants in the same maxilla.&#xD;
      The teeth must have been removed at least 4-6 months before implant placement. The minimum&#xD;
      required bone height would be 6mm, which would be determined by an orthopantomography (1: 1)&#xD;
      to be performed in all cases. The space where the implants are placed should have sufficient&#xD;
      bone volume that does not require regeneration (height&gt; 6mm and bone width&gt; 5mm). If&#xD;
      expansion is to be done, it should be done in both techniques. The minimum distance from one&#xD;
      implant to the adjacent teeth should be at least 1.5 mm, and in the case of two or more&#xD;
      adjacent implants, at least 3 mm between them.&#xD;
&#xD;
      Intervention 150 implants will be placed (50 of external connection and 100 of internal&#xD;
      connection: 50 with design for infracrestal placement and crestal-level.) Following the&#xD;
      inclusion criteria, patients should require the replacement of at least two teeth in the same&#xD;
      jaw.&#xD;
&#xD;
      To randomize we will use the application created by a computer programmer that generates&#xD;
      random numbers.&#xD;
&#xD;
      All implants will be placed by the students of 3rd of Master, using the same surgical&#xD;
      protocol.&#xD;
&#xD;
      Post-operative monitoring and follow-up visits Once the implants are placed, a period of&#xD;
      osseointegration of 4 months will be left in the maxilla and 3 in the mandible. The control&#xD;
      visits to assess clinical aspects were performed by the principal investigator at the&#xD;
      following times: (0) prior to implant placement, (1) implant placement, (2) at 7 (+/- 1) days&#xD;
      of placing the implant, where it will be used to remove the suture, (3) within 15 days (+/- 2&#xD;
      days) of placing the implant, (4) one month after placement, (5) 3 months (+/- 2 weeks) if it&#xD;
      is placed in the mandible and at 4 months (+/- 2 weeks) in the jaw, when the healing pillar&#xD;
      will be placed, (6) one week later, ) (+/- 1 day) at the printing press, (8) at 7 (+/- 1&#xD;
      day), where a metal test would be performed and (9) in the following week (+/- 1 Day), in the&#xD;
      placement of the prosthesis, (10) 6 months after placement of the prosthesis and (11) 12&#xD;
      months after placement of the prosthesis.&#xD;
&#xD;
      The X-ray control, to compare bone loss, would be performed by an independent evaluator at&#xD;
      the following times: (T1) prior to implant placement, (T2) on the day of implant placement,&#xD;
      (T3) per month, (T4) at the time of placement of the implant Prosthesis (without specifying&#xD;
      in which month), (T5) at 6 months after loading and (T6) one year after occlusal loading.&#xD;
&#xD;
      The stability implants, would be performed by an independent evaluator using the analysis of&#xD;
      the resonance frequency (Penguin device) The measurements will be made the day of implant&#xD;
      placement, the day of placement of the healing abutment (two-three months after implant&#xD;
      placement) and the day of delivery of the crown (3-4 months after placement of the implant)&#xD;
&#xD;
      Study variables - Primary study variables: Percentage of bone loss&#xD;
&#xD;
      - Secondary study variables: Tobacco consumption Plate Index (PLI) Bleeding index (SBI)&#xD;
      Implant stability ratio (ISQ) Intra and postoperative parameters&#xD;
&#xD;
      Statistic analysis The data will be entered into an Excel database and processed using the&#xD;
      statistical package (SPSS )Windows. The level of statistical significance will be p &lt;0.05.&#xD;
&#xD;
      A descriptive study of all the variables and the relationship between bone loss and the&#xD;
      implant system or the different variables will be analyzed by the t-student for the&#xD;
      independent data or by non-parametric tests (Mann-W-U ) If the distribution is not normal.&#xD;
&#xD;
      The Chi-squared test will be used to analyze the qualitative variables. Multiple regression&#xD;
      analysis will be used to evaluate the association between the dependent variable (bone loss&#xD;
      at 0, 1, 4, 6 and 12 months) and the independent variables, internal connection or external&#xD;
      connection. All the variables that could potentially affect the study relationship, such as&#xD;
      age, sex, smoking, and oral hygiene, were used as control variables in the regression.&#xD;
&#xD;
      Blind study&#xD;
&#xD;
      Ethical aspects The study would be carried out in accordance with the general recommendations&#xD;
      of the 1964 Declaration of Helsinki for biomedical research in humans.&#xD;
&#xD;
      Eligible patients would be explained in detail to the study protocol and given an information&#xD;
      sheet to those who enroll, they would be given to sign two informed consents; The first,&#xD;
      explaining the risk and complications derived from implant placement surgery and the second&#xD;
      where they agree to participate in the study. All patients will have a medical history and a&#xD;
      data collection sheet attached to their history&#xD;
    </textblock>
  </detailed_description>
  <overall_status>Unknown status</overall_status>
  <last_known_status>Active, not recruiting</last_known_status>
  <start_date type="Actual">May 8, 2017</start_date>
  <completion_date type="Anticipated">February 17, 2022</completion_date>
  <primary_completion_date type="Actual">January 30, 2020</primary_completion_date>
  <phase>N/A</phase>
  <study_type>Interventional</study_type>
  <has_expanded_access>No</has_expanded_access>
  <study_design_info>
    <allocation>Randomized</allocation>
    <intervention_model>Parallel Assignment</intervention_model>
    <intervention_model_description>To randomize we will use the application created by a computer programmer that generates random numbers.&#xD;
In each jaw, each edentulous space will be randomly assigned (A, B, C, D, ..). Following the alphabetical order to each letter will be assigned randomly the connection to use, as detailed below:&#xD;
2 edentulous spaces: A: c. External or c. Internal (random) B: the one that is pending (The type of internal connection (crestal or infracrestal) will be chosen at random.)&#xD;
3 edentulous spaces: A: c. External, c. Crestal or infracrestal internal B: randomly choose between the two remaining options C: the one that is pending</intervention_model_description>
    <primary_purpose>Treatment</primary_purpose>
    <masking>Single (Participant)</masking>
    <masking_description>Blind study The RX examiner and the person performing the resonance frequency measurements would be independent of the surgeons who placed the implants.</masking_description>
  </study_design_info>
  <primary_outcome>
    <measure>A COMPARISON BETWEEN THE DIFFERENT CONNECTIONS AND POSITIONING OF THE IMPLANTS REGARDING THE BONE OF LOSS</measure>
    <time_frame>1,4 years around</time_frame>
    <description>By means of measurements in millimeters in the radiographs, the loss of bone will be compared. These measurements will be made one month after the placement of the implant, at 3-4 months in the placement of the crown, 6 months after placement of the crown and one year after placement of the crown</description>
  </primary_outcome>
  <other_outcome>
    <measure>ANALYSIS OF THE RESONANCE FREQUENCY</measure>
    <time_frame>4-5months around</time_frame>
    <description>Using the Penguin device, the investigators measure the coefficient of stability of the implant. Measurements will be made the day of implant placement, the day of placement of the healing abutment (two-three months after implant placement) and the day of delivery of the crown (3-4 months after placement Of the implant)</description>
  </other_outcome>
  <number_of_arms>3</number_of_arms>
  <enrollment type="Anticipated">20</enrollment>
  <condition>Dental Implants</condition>
  <arm_group>
    <arm_group_label>External-Connection non-submerged Imp</arm_group_label>
    <arm_group_type>Experimental</arm_group_type>
    <description>We will place implants with external connection and non- submerged to assess the bone loss around</description>
  </arm_group>
  <arm_group>
    <arm_group_label>Internal Connection Submerged implants</arm_group_label>
    <arm_group_type>Experimental</arm_group_type>
    <description>We will place implants with internal connection and submerged to assess the bone loss around</description>
  </arm_group>
  <arm_group>
    <arm_group_label>Internal Connection non-Submerged Impl</arm_group_label>
    <arm_group_type>Experimental</arm_group_type>
    <description>We will place Internal connection implant and non-Submerged Implants to assess the bone loss around</description>
  </arm_group>
  <intervention>
    <intervention_type>Device</intervention_type>
    <intervention_name>External-Connection non-submerged Imp</intervention_name>
    <description>Through a surgical procedure, we will implant implant whit external connection and non submerged to patients.</description>
    <arm_group_label>External-Connection non-submerged Imp</arm_group_label>
  </intervention>
  <intervention>
    <intervention_type>Device</intervention_type>
    <intervention_name>Internal Connection Submerged implants</intervention_name>
    <description>Through a surgical procedure, we will implant implant whit internal connection and submerged to patients.</description>
    <arm_group_label>Internal Connection Submerged implants</arm_group_label>
  </intervention>
  <intervention>
    <intervention_type>Device</intervention_type>
    <intervention_name>Internal Connection non-Submerged Impl</intervention_name>
    <description>Through a surgical procedure, we will implant implant whit internal connection and non-submerged to patients.</description>
    <arm_group_label>Internal Connection non-Submerged Impl</arm_group_label>
  </intervention>
  <eligibility>
    <criteria>
      <textblock>
        Inclusion Criteria:&#xD;
&#xD;
          -  Patients of general age who present partial edentulism in the mandible and / or&#xD;
             maxilla and require the replacement of at least 2 teeth by implants in the same&#xD;
             maxilla.&#xD;
&#xD;
          -  The teeth must have been removed at least 4-6 months before implant placement.&#xD;
&#xD;
          -  The minimum required bone height would be 6mm, which would be determined by an&#xD;
             orthopantomography (1: 1)&#xD;
&#xD;
        Exclusion Criteria:&#xD;
&#xD;
          -  History of use of bisphosphonates&#xD;
&#xD;
          -  Evidence of serious systemic diseases such as recent infarction&#xD;
&#xD;
          -  Uncontrolled diabetes, coagulation disorders, cancer, psychiatric contraindications,&#xD;
&#xD;
          -  Active infection in the area of the implants&#xD;
&#xD;
          -  Absence of an antagonist in the area of implant placement&#xD;
&#xD;
          -  Pharmacological treatments capable of affecting gingival health&#xD;
&#xD;
          -  Pregnant or lactating women.&#xD;
      </textblock>
    </criteria>
    <gender>All</gender>
    <minimum_age>N/A</minimum_age>
    <maximum_age>N/A</maximum_age>
    <healthy_volunteers>Accepts Healthy Volunteers</healthy_volunteers>
  </eligibility>
  <overall_official>
    <last_name>Natalia Palacios Garzón, PhD student</last_name>
    <role>Principal Investigator</role>
    <affiliation>HUBellvitge Recruiting</affiliation>
  </overall_official>
  <overall_official>
    <last_name>José López López, PhD</last_name>
    <role>Study Director</role>
    <affiliation>Hospital Universitari de Bellvitge</affiliation>
  </overall_official>
  <location>
    <facility>
      <name>Natalia Palacios Garzon</name>
      <address>
        <city>Barcelona</city>
        <zip>08232</zip>
        <country>Spain</country>
      </address>
    </facility>
  </location>
  <location_countries>
    <country>Spain</country>
  </location_countries>
  <reference>
    <citation>Pozzi A, Tallarico M, Moy PK. Three-year post-loading results of a randomised, controlled, split-mouth trial comparing implants with different prosthetic interfaces and design in partially posterior edentulous mandibles. Eur J Oral Implantol. 2014 Spring;7(1):47-61.</citation>
    <PMID>24892113</PMID>
  </reference>
  <reference>
    <citation>Penarrocha-Diago MA, Flichy-Fernandez AJ, Alonso-Gonzalez R, Penarrocha-Oltra D, Balaguer-Martinez J, Penarrocha-Diago M. Influence of implant neck design and implant-abutment connection type on peri-implant health. Radiological study. Clin Oral Implants Res. 2013 Nov;24(11):1192-200. doi: 10.1111/j.1600-0501.2012.02562.x. Epub 2012 Aug 28.</citation>
    <PMID>22925048</PMID>
  </reference>
  <reference>
    <citation>Galindo-Moreno P, Fernandez-Jimenez A, O'Valle F, Monje A, Silvestre FJ, Juodzbalys G, Sanchez-Fernandez E, Catena A. Influence of the crown-implant connection on the preservation of peri-implant bone: a retrospective multifactorial analysis. Int J Oral Maxillofac Implants. 2015 Mar-Apr;30(2):384-90. doi: 10.11607/jomi.3804.</citation>
    <PMID>25830399</PMID>
  </reference>
  <verification_date>September 2021</verification_date>
  <study_first_submitted>July 20, 2017</study_first_submitted>
  <study_first_submitted_qc>July 24, 2017</study_first_submitted_qc>
  <study_first_posted type="Actual">July 28, 2017</study_first_posted>
  <last_update_submitted>September 6, 2021</last_update_submitted>
  <last_update_submitted_qc>September 6, 2021</last_update_submitted_qc>
  <last_update_posted type="Actual">September 13, 2021</last_update_posted>
  <responsible_party>
    <responsible_party_type>Principal Investigator</responsible_party_type>
    <investigator_affiliation>University of Barcelona</investigator_affiliation>
    <investigator_full_name>Natalia Palacios Garzón</investigator_full_name>
    <investigator_title>PhD student (Universitat de Barcelona)</investigator_title>
  </responsible_party>
  <keyword>Bone loss, dental implant desing</keyword>
  <!-- Results have not yet been posted for this study                                          -->
</clinical_study>


download date: ClinicalTrials.gov processed this data on September 20, 2023
link text: Link to the current ClinicalTrials.gov record.
url: https://clinicaltrials.gov/ct2/show/NCT03232372
org study id: HUB
nct id: NCT03232372
lead sponsor: 
has dmc: Yes
is fda regulated drug: No
is fda regulated device: No
When an implant is placed, it is assumed that there will be a loss of bone in the more
      coronal area around it. The placement of the implant in relation to bone level, either
      crestal or subcrestal and the type of connection chosen, either external connection or
      internal connection, have been related as one of the factors that caused this loss. The
      preservation of the peri-implant bone influences the shape and contour of the underlying soft
      tissues, which are important for the aesthetic result of the treatment and for the success of
      the same.

      Hypothesis: The hypothesis is that there are no differences between the external and internal
      connection with regard to marginal bone loss. In implants placed at the crestal and
      subcrestal level, the hypothesis is that there is greater marginal bone loss in implants
      placed at the subcrestal level.

      Objectives: Main: To evaluate the marginal bone loss around implants of internal connection
      and external connection. Secondary: To compare the loss of bone in implants of internal
      connection placed at crestal and subcrestal level. To evaluate intra and post-operative
      complications.

      Material and methods: A prospective and randomized radiological study will be performed. 150
      implants will be placed in patients who must present partial edentulism and require the
      replacement of at least 2 crowns on implants in the same jaw. In a randomized manner,
      implants of external connection and internal connection will be placed. Other features such
      as surface treatment type of the implant will be similar in both types of implants to reduce
      bias.

      With this study the investigators will try to define if there is a procedure in when to the
      connection of the implant and the location of this, that is more beneficial with respect to
      the preservation of bone.
Implant dentistry has undergone major development and expansion since the nineteen sixties,
      when Dr. Branemark (Sweden) introduced the concept of osseointegration. The use of implants
      to replace missing teeth and restore function has presented a high success rate and long-term
      survival. For this reason rehabilitation by means of implants has become standard and well
      accepted by patients, who increasingly demand treatments offering greater comfort and
      aesthetics. Implant-based treatments must fulfill a range of physiological, functional and
      aesthetic criteria before they can be considered successful. These include osseointegration
      stability and duration, absence of pathological processes, and aesthetics that satisfy the
      patient.

      There are diverse types of implants and corresponding systems that connect the implant to the
      prosthesis. Implant connections fall into two main groups: External and Internal Connection.

      When an implant is placed, it is estimated that there will be bone loss around this during
      the first year, both horizontally and vertically. Actually is considered successful if the
      loss of crestal bone around the implant is less than 1.5mm during the first year and less
      than 0.2 annually in the next. This bone loss continues to occur despite the new designs of
      implants that try to stop it. The preservation of the peri-implant bone is an important
      factor for the success of the same. The quantity and quality influence the shape and contour
      of the overlying soft tissues, which are important for the aesthetic result of the treatment.
      The hypothesis is that there are no differences between the external and internal connection
      with regard to marginal bone loss. In implants placed at the crestal and subcrestal level,
      the hypothesis is that more marginal bone is loss in implants placed at the subcrestal level
      design.

      A prospective randomized controlled, split-mouth clinical trial with a sample size of 50
      implants per arm is proposed.

      Population of the study Patients attended in HOUB (Hospital Odontológico Universitario de
      Bellvitge. Master of Medicine Surgery and Implantology and Master of Dentistry in Oncology
      and Immunocompromised Patients).

      Inclusion criteria Patients of general age who present partial edentulism in the mandible and
      / or maxilla and require the replacement of at least 2 teeth by implants in the same maxilla.
      The teeth must have been removed at least 4-6 months before implant placement. The minimum
      required bone height would be 6mm, which would be determined by an orthopantomography (1: 1)
      to be performed in all cases. The space where the implants are placed should have sufficient
      bone volume that does not require regeneration (height> 6mm and bone width> 5mm). If
      expansion is to be done, it should be done in both techniques. The minimum distance from one
      implant to the adjacent teeth should be at least 1.5 mm, and in the case of two or more
      adjacent implants, at least 3 mm between them.

      Intervention 150 implants will be placed (50 of external connection and 100 of internal
      connection: 50 with design for infracrestal placement and crestal-level.) Following the
      inclusion criteria, patients should require the replacement of at least two teeth in the same
      jaw.

      To randomize we will use the application created by a computer programmer that generates
      random numbers.

      All implants will be placed by the students of 3rd of Master, using the same surgical
      protocol.

      Post-operative monitoring and follow-up visits Once the implants are placed, a period of
      osseointegration of 4 months will be left in the maxilla and 3 in the mandible. The control
      visits to assess clinical aspects were performed by the principal investigator at the
      following times: (0) prior to implant placement, (1) implant placement, (2) at 7 (+/- 1) days
      of placing the implant, where it will be used to remove the suture, (3) within 15 days (+/- 2
      days) of placing the implant, (4) one month after placement, (5) 3 months (+/- 2 weeks) if it
      is placed in the mandible and at 4 months (+/- 2 weeks) in the jaw, when the healing pillar
      will be placed, (6) one week later, ) (+/- 1 day) at the printing press, (8) at 7 (+/- 1
      day), where a metal test would be performed and (9) in the following week (+/- 1 Day), in the
      placement of the prosthesis, (10) 6 months after placement of the prosthesis and (11) 12
      months after placement of the prosthesis.

      The X-ray control, to compare bone loss, would be performed by an independent evaluator at
      the following times: (T1) prior to implant placement, (T2) on the day of implant placement,
      (T3) per month, (T4) at the time of placement of the implant Prosthesis (without specifying
      in which month), (T5) at 6 months after loading and (T6) one year after occlusal loading.

      The stability implants, would be performed by an independent evaluator using the analysis of
      the resonance frequency (Penguin device) The measurements will be made the day of implant
      placement, the day of placement of the healing abutment (two-three months after implant
      placement) and the day of delivery of the crown (3-4 months after placement of the implant)

      Study variables - Primary study variables: Percentage of bone loss

      - Secondary study variables: Tobacco consumption Plate Index (PLI) Bleeding index (SBI)
      Implant stability ratio (ISQ) Intra and postoperative parameters

      Statistic analysis The data will be entered into an Excel database and processed using the
      statistical package (SPSS )Windows. The level of statistical significance will be p <0.05.

      A descriptive study of all the variables and the relationship between bone loss and the
      implant system or the different variables will be analyzed by the t-student for the
      independent data or by non-parametric tests (Mann-W-U ) If the distribution is not normal.

      The Chi-squared test will be used to analyze the qualitative variables. Multiple regression
      analysis will be used to evaluate the association between the dependent variable (bone loss
      at 0, 1, 4, 6 and 12 months) and the independent variables, internal connection or external
      connection. All the variables that could potentially affect the study relationship, such as
      age, sex, smoking, and oral hygiene, were used as control variables in the regression.

      Blind study

      Ethical aspects The study would be carried out in accordance with the general recommendations
      of the 1964 Declaration of Helsinki for biomedical research in humans.

      Eligible patients would be explained in detail to the study protocol and given an information
      sheet to those who enroll, they would be given to sign two informed consents; The first,
      explaining the risk and complications derived from implant placement surgery and the second
      where they agree to participate in the study. All patients will have a medical history and a
      data collection sheet attached to their history
allocation: Randomized
intervention model: Parallel Assignment
intervention model description: To randomize we will use the application created by a computer programmer that generates random numbers.
In each jaw, each edentulous space will be randomly assigned (A, B, C, D, ..). Following the alphabetical order to each letter will be assigned randomly the connection to use, as detailed below:
2 edentulous spaces: A: c. External or c. Internal (random) B: the one that is pending (The type of internal connection (crestal or infracrestal) will be chosen at random.)
3 edentulous spaces: A: c. External, c. Crestal or infracrestal internal B: randomly choose between the two remaining options C: the one that is pending
primary purpose: Treatment
masking: Single (Participant)
masking description: Blind study The RX examiner and the person performing the resonance frequency measurements would be independent of the surgeons who placed the implants.
measure: A COMPARISON BETWEEN THE DIFFERENT CONNECTIONS AND POSITIONING OF THE IMPLANTS REGARDING THE BONE OF LOSS
time frame: 1,4 years around
description: By means of measurements in millimeters in the radiographs, the loss of bone will be compared. These measurements will be made one month after the placement of the implant, at 3-4 months in the placement of the crown, 6 months after placement of the crown and one year after placement of the crown
measure: ANALYSIS OF THE RESONANCE FREQUENCY
time frame: 4-5months around
description: Using the Penguin device, the investigators measure the coefficient of stability of the implant. Measurements will be made the day of implant placement, the day of placement of the healing abutment (two-three months after implant placement) and the day of delivery of the crown (3-4 months after placement Of the implant)
arm group label: External-Connection non-submerged Imp
arm group type: Experimental
description: We will place implants with external connection and non- submerged to assess the bone loss around
arm group label: Internal Connection Submerged implants
arm group type: Experimental
description: We will place implants with internal connection and submerged to assess the bone loss around
arm group label: Internal Connection non-Submerged Impl
arm group type: Experimental
description: We will place Internal connection implant and non-Submerged Implants to assess the bone loss around
intervention type: Device
intervention name: External-Connection non-submerged Imp
description: Through a surgical procedure, we will implant implant whit external connection and non submerged to patients.
arm group label: External-Connection non-submerged Imp
intervention type: Device
intervention name: Internal Connection Submerged implants
description: Through a surgical procedure, we will implant implant whit internal connection and submerged to patients.
arm group label: Internal Connection Submerged implants
intervention type: Device
intervention name: Internal Connection non-Submerged Impl
description: Through a surgical procedure, we will implant implant whit internal connection and non-submerged to patients.
arm group label: Internal Connection non-Submerged Impl
criteria: 
gender: All
minimum age: N/A
maximum age: N/A
healthy volunteers: Accepts Healthy Volunteers
last name: Natalia Palacios Garzón, PhD student
role: Principal Investigator
affiliation: HUBellvitge Recruiting
last name: José López López, PhD
role: Study Director
affiliation: Hospital Universitari de Bellvitge
facility: 
country: Spain
citation: Pozzi A, Tallarico M, Moy PK. Three-year post-loading results of a randomised, controlled, split-mouth trial comparing implants with different prosthetic interfaces and design in partially posterior edentulous mandibles. Eur J Oral Implantol. 2014 Spring;7(1):47-61.
PMID: 24892113
citation: Penarrocha-Diago MA, Flichy-Fernandez AJ, Alonso-Gonzalez R, Penarrocha-Oltra D, Balaguer-Martinez J, Penarrocha-Diago M. Influence of implant neck design and implant-abutment connection type on peri-implant health. Radiological study. Clin Oral Implants Res. 2013 Nov;24(11):1192-200. doi: 10.1111/j.1600-0501.2012.02562.x. Epub 2012 Aug 28.
PMID: 22925048
citation: Galindo-Moreno P, Fernandez-Jimenez A, O'Valle F, Monje A, Silvestre FJ, Juodzbalys G, Sanchez-Fernandez E, Catena A. Influence of the crown-implant connection on the preservation of peri-implant bone: a retrospective multifactorial analysis. Int J Oral Maxillofac Implants. 2015 Mar-Apr;30(2):384-90. doi: 10.11607/jomi.3804.
PMID: 25830399
responsible party type: Principal Investigator
investigator affiliation: University of Barcelona
investigator full name: Natalia Palacios Garzón
investigator title: PhD student (Universitat de Barcelona)