A study to compare how different thickness of dental mouth guards affect jaw muscles and teeth alignment in people with worn teeth

study groups According to the random allocation process, selected subjects will be divided into two groups including 10 subjects in each group. The first group is group A that will receive occlusal splints with 3 mm thick . Wearing 3 mm thick occlusal splint for two week then wore splint 6mm for two week after wash period to retrun muscle activity to normale state The second group is group B that will receive occlusal splint of 6 mm thick to be used for two weeks then wore splint 3mm for two week after wash period to retrun muscle activity to normale state Methodology of determining Vertical dimension of occlusion (VDO) Both techniques of intra and extra oral measurements of VDO will be used to determine loss of VDO. For intra oral measurement, distance from gingival margins of maxillary central incisor to the gingival margin of lower incisor will be measured& should be more than 18 mm, if the distance less than 18 mm then VDO is lost For extra oral measurements of (VDO) Willis Method will be used to measure the distance between the base of the nose to the chin in rest position to measure the vertical dimension of rest, then if the freeway space is more than 6 mm, the (VDO) is lost The amount of increase is accomplished on the articulator with adjustment of vertical pin on the articulator which is graduated in millimetres). Methodology of splint fabrication Impressions of both the maxillary and mandibular arches will be made using silicon impression material and the casts will be poured in dental stone product. The cast models will be mounted on full adjustable articulator using face bow transfer and interocclusal records in centric relation. Vertical dimension will be increased by 3mm and 6mm by adjusting the incisal guide pin of the articulator. Stabilization splints will be constructed by adapting heat acrylic on mandibular casts and occlusal surfaces will be modified with polymerizing acrylic resin to incorporate the contact of all maxillary teeth in centric relation. The articulator will close to the vertical dimension established by the incisal pin. The acrylic will be slightly indented by all the teeth. All the excess on occlusal surfaces will be trimmed back and excess of sheets will be trimmed away flush with buccal and labial margins to cover 2mm from the incisal edges or cusp tips on the buccal side. On lingual side, the sheets will extend 1-1.5 mm from the cervical margins. The anterior bite plane will be flat and extend 1 mm in protrusive and lateral excursions. The splint will be carefully finish and highly polished to ensure comfort of the patient while wearing it. Fit and occlusion of stabilization splints will also be verified in patients’ mouths. Patients will be instructed to wear the splint all day and night except during eating. All patients will be followed for adjustments and follow up two week after insertion , for two groups . All splints will be fabricated by one operator to avoid variation in appliance construction. • Wear Protocol: The patients were advised to use the occlusal splint on a 24-hour round-the-clock basis (24 hours/day), unless during meals and oral health activities. • Follow-up: The attendance at wearing schedule during the two weeks of adaptation period was followed up in order to guarantee strict compliance to the program.