entity and repository pattern with ninject, Dispose Issue

I have build my site using entity and repository pattern with ninject injection. My problem is my connections don't seem to get disposed. I have around 30 repositories (one for each table) and I get sql expiration timout preety quick. I can't use the regular using statement because the code recognize only the interface before the injection. (in each controler I have my repositories interface instances which get injected via ninject).
 
I have searched the net but couldn't find a solution that was accurate for me. can anyone please help me? code example:
 
this is in the ninject controller under addBindings():
 

 ninjectKernel.Bind<IMovieRepository>().To<MovieRepository>().InRequestScope();

 
and one of my repositories:
 

public class MovieRepository : IMovieRepository, IDisposable 
        {
         private Entities dataContext = new Entities();
         public System.Data.Entity.DbContext DbContext 
         {
            get { return dataContext ?? (dataContext = new Entities()); } 
         }
         public void Dispose() { dataContext.Dispose(); }
        }

 
and in the Global.asax file:
 

ControllerBuilder.Current.SetControllerFactory(new NinjectControllerFactory() as IControllerFactory);