<prompt> In WHO classification of periradicular diseases code no. KO4.4 representsAcute apical periodontitisChronic apical periodontitisPeriapical abscessRadicular cyst  <response>: WHO classification of periradicular diseasesKO4.4...acute apical periodontitisKO4.5...chronic apical periodontitisKO4.6...periapical abscess with sinusKO4.7...periapical abscess without sinusKO4.8...radicular cyst 