Purpose: Evaluation of survival rate for three space maintainers (SMs) of different designs versus standard one.

Methods: 52 extraction sites in children of age group of 4-7 years with prematurely-lost 1st primary molar were selected for this study. The whole sample was divided into four groups (13 each). In Group I, Band and loop (B&L), Group II: Single-sided band and loop (Ss B&L), Group III: Direct bonded wire (DBW), Group IV: Tube and loop (T&L). children were recalled at 3, 6, 9, 12,15-month.

Purpose: Evaluation of survival rate for three space maintainers (SMs) of different designs versus standard one.

Methods: 52 extraction sites in children of age group of 4-7 years with prematurely-lost 1st primary molar were selected for this study. The whole sample was divided into four groups (13 each). In Group I, Band and loop (B&L), Group II: Single-sided band and loop (Ss B&L), Group III: Direct bonded wire (DBW), Group IV: Tube and loop (T&L). children were recalled at 3, 6, 9, 12,15-month. Cumulative survival rates of SMs were estimated by means of Kaplan-Meier method with log rank test. Cumulative survival rates of SMs were estimated by means of Kaplan-Meier method with log rank test. Sample size: The total sample size was calculated using Sampsize application with anticipated success on treatment with conventional band and loop 86% , anticipated response on treatment with direct bonded wire 33% 12, at 80% power, and significant level 0.05.

Inclusion Criteria:

1. Children and their parents showed cooperation and compliance.
2. Extraction of the first primary molar was not exceeding three months.
3. Angle's class 1 occlusion with normal deciduous molar relation
4. Child not complaining from any systemic disease.
5. The extraction space was of only one missing first deciduous molar with remaining teeth present on mesial and distal side of extraction space.
6. Absence of para-functional habits or abnormal occlusion conditions such as crossbite, open bite, deep bite.
7. No restorative application on the buccal surfaces of abutment teeth, otherwise extra-coronal complete coverage, as stainless-steel crown, was applied only in banded groups.
8. Radiographically, presence of permanent successor.
9. Absence of any pathological evidence on the eruption track of the permanent tooth.
10. Ability to attend follow-up appointments as required.

Exclusion Criteria:

1. Child complaining from any systemic disease.
2. Prescence of para-functional habits or abnormal occlusion conditions such as crossbite, open bite, deep bite
3. Extraction of the first primary molar was exceeding three months.
4. The extraction space resulted from more than one missing deciduous molar
5. Radiographically, absence of permanent successor.