How to get complete object with entity framework on same instance?

I have the following entities:

public partial class ApplicationIntegration
{
    public int IntegrationId { get; set; }
    public int ApplicationId { get; set; }
    public bool ReceivesData { get; set; }
    public bool SendsData { get; set; }

    public virtual Application Application { get; set; }
}

public partial class Application
{
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
    public Application()
    {
        this.ApplicationIntegrations = new HashSet<ApplicationIntegration>();
    }

    public int ApplicationId { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public bool IsActive { get; set; }

    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
    public virtual ICollection<ApplicationIntegration> ApplicationIntegrations { get; set; }
}

Now, this is my class where I add and get a application integration:

public class ApplicationIntegrationsRepository : Repository
    {
        /// <summary>
        /// Method to add a new application integration
        /// </summary>
        /// <param name="applicationIntegration"></param>
        /// <returns></returns>
        public ApplicationIntegration AddApplicationIntegration(ApplicationIntegration applicationIntegration)
        {
            if (applicationIntegration != null)
            {
                Db.ApplicationIntegrations.Add(applicationIntegration);
                int outPut = Db.SaveChanges();

                //If record was inserted correctly
                if (outPut > 0)
                {
                    //Revive object
                    Db.Entry(applicationIntegration).GetDatabaseValues();
                    applicationIntegration = GetApplicationIntegrationById(applicationIntegration.IntegrationId);
                }
            }

            return applicationIntegration;
        }

        /// <summary>
        /// Method to get a specific application integration by ID
        /// </summary>
        /// <param name="applicationIntegrationId"></param>
        /// <returns></returns>
        public ApplicationIntegration GetApplicationIntegrationById(int applicationIntegrationId)
        {
            ApplicationIntegration applicationIntegration = Db.ApplicationIntegrations.FirstOrDefault(a => a.IntegrationId == applicationIntegrationId);
            return applicationIntegration;
        }
    }


public abstract class Repository
    {
        /// <summary>
        /// Example Entities Connection String
        /// </summary>
        protected ExampleEntities Db { get; set; }

        /// <summary>
        /// Repository Constructor
        /// </summary>
        protected Repository()
        {
            Db = new ExampleEntities();
        }
    }

When passing the variable onto AddApplicationIntegration, I only include the simple variables (IntegrationId = 0, ApplicationId = {id of the application}, ReceivesData = {true or false}, SendsData = {true or false}). I leave Application as null.

Then I add to DB, it inserts correctly. However once I retrieve the object even if calling GetApplicationIntegrationById afterwards, it will always return the property Application as null.

I found a work around to this.

ApplicationIntegrationsRepository _applicationIntegrationsRepository = new ApplicationIntegrationsRepository();
ApplicationIntegration applicationIntegration = new ApplicationIntegration{IntegrationId = 0, ApplicationId = 1, ReceivesData = false, SendsData = true};
ApplicationIntegration entityObject = _applicationIntegrationsRepository.AddApplicationIntegration(applicationIntegration);
ApplicationIntegration applicationNull = _applicationIntegrationsRepository.GetApplicationIntegrationById(entityObject.IntegrationId);
ApplicationIntegration applicationNotNull = new ApplicationIntegrationsRepository().GetApplicationIntegrationById(entityObject.IntegrationId);

If I declare another instance, it will get the full object. I believe this has to do something with the db connection that is created.

Any ideas on how to retrieve using the same instance?