## 3 Results
### Alveolar Bone Crest Level (RCF Versus Non-RCF Teeth)
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  & & \multicolumn{8}{c}{**Pooled Age-Related Distances CEJ—Alveolar Bone Crest**} \\  & & \multicolumn{8}{c}{**in the Matching Pairs of RCF and n-RCF Teeth**} \\ \hline \multirow{2}{*}{**Age**} & **No of** & **Measuring** & \multirow{2}{*}{**RCF**} & **Mean** & **CI** & **Range** & **Pooled** & \multirow{2}{*}{**sd**} & **Min** & **Max** \\  & **Teeth** & **Points** & & & **[mm]** & **[95\%]** & & & **Mean** & **Mean** & **sd** & **Min** & **Max** \\ \hline
18–25 & 24 & 96 & yes & 2.153 & 1.85–2.57 & 0.72 & & & & & & \\  & & & no & 2.147 & 1.83–2.36 & 0.53 & & & & & \\
26–30 & 28 & 112 & yes & 2.154 & 1.86–2.60 & 0.74 & & & & & \\  & & & no & 2.149 & 1.84–2.33 & 0.49 & & & & & \\
31–35 & 30 & 120 & yes & 2.170 & 1.90–2.41 & 0.51 & & & & & \\  & & & no & 2.165 & 1.80–2.48 & 0.68 & & & & \\
36–40 & 48 & 192 & yes & 2.201 & 1.85–2.59 & 0.74 & & & & \\  & & & no & 2.200 & 1.80–2.35 & 0.55 & & & & \\
41–45 & 76 & 304 & yes & 2.605 & 2.28–2.90 & 0.62 & & & & \\  & & & no & 2.597 & 2.12–2.72 & 0.60 & & & & \\
46–50 & 66 & 264 & yes & 2.825 & 2.56–3.09 & 0.53 & & & & \\  & & & no & 2.895 & 2.59–3.19 & 0.60 & & & & \\
51–55 & 56 & 224 & yes & 2.957 & 2.50–3.41 & 0.91 & & & & \\  & & & no & 2.782 & 2.35–3.20 & 0.85 & & & & \\
56–60 & 52 & 208 & yes & 2.962 & 2.70–3.34 & 0.64 & & & & \\  & & & no & 2.783 & 2.69–3.25 & 0.56 & & & & \\
61–65 & 42 & 168 & yes & 2.783 & 2.51–2.95 & 0.44 & & & & \\  & & & no & 2.887 & 2.60–3.28 & 0.68 & & & & \\
66–70 & 30 & 120 & yes & 2.980 & 2.17–3.76 & 1.59 & & & & \\  & & & no & 2.966 & 2.56–3.31 & 0.75 & & & & \\
71 plus & 18 & 72 & yes & 2.935 & 2.00–3.87 & 1.87 & & & & \\  & & & no & 2.901 & 1.89–3.91 & 2.02 & & & & \\ \hline \multirow{2}{*}{total} & \multirow{2}{*}{\(\Sigma\)470} & \multirow{2}{*}{\(\Sigma\)1880} & \multirow{2}{*}{\(-\)} & \multirow{2}{*}{\(-\)} & & & & & & \\  & & & & & & & & & & \\  & & & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Pooled age-related distances CEJ—alveolar bone crest in the matching pairs of RCF and n-RCF teeth. CI-interval, range, mean, sd, min and max. Different superscript letters indicate statistical significance (_p_ < 0.05). \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Gender** & **No of** & **Age** & **RCF** & & **Meali** & **Distal** & **Lingual/ Palatal** & **Buccal** & **Mean** & **Pooled Mean** \\  & **Teeth** & **Age** & & & & & & & \\  & & & yes & mean \(\pm\) sd & 2.68 \(\pm\) 1.13 & 2.77 \(\pm\) 1.50 & 2.81 \(\pm\) 1.31 & 2.74 \(\pm\) 1.25 & 2.74 \(\pm\) 1.35 & \\ \multirow{4}{*}{men} & \multirow{4}{*}{\(50.03\pm 10.56\)} & & 95\% CI & 2.33–2.82 & 2.56–3.23 & 2.38–2.91 & 2.53–3.01 & & \\  & & & range & 0.49 & 0.67 & 0.59 & 0.53 & 0.48 & 2.73 \({}^{\pm}\) 1.25 \\  & & & no & mean \(\pm\) sd & 2.67 \(\pm\) 1.12 & 2.73 \(\pm\) 1.38 & 2.76 \(\pm\) 1.29 & 2.75 \(\pm\) 1.18 & 2.72 \(\pm\) 1.16 & 2.60–2.91 \\  & & & 95\% CI & 2.40–2.95 & 2.50–2.97 & 2.55–3.01 & 2.56–3.06 & 2.55–2.94 & 0.31 \\  & & & range & 0.45 & 0.47 & 0.46 & 0.50 & 0.39 & \\ \hline \hline men & & & _p_-value & 0.848 & 0.648 & 0.494 & 0.851 & 0.718 & & \\ \hline female & 141 & & yes & mean \(\pm\) sd & 2.59 \(\pm\) 1.41 & 2.62 \(\pm\) 1.10 & 2.49 \(\pm\) 1.03 & 2.49 \(\pm\) 1.03 & 2.54 \(\pm\) 1.18 & & \\  & & & 95\% CI & 2.30–2.64 & 2.33–2.73 & 2.43–2.79 & 2.35–2.69 & 2.39–2.68 & & \\  & & & range & 0.34 & 0.40 & 0.36 & 0.34 & 0.29 & & \\  & & & & & & & & & \\ \hline \hline \multirow{2}{*}{female} & \multirow{2}{*}{\(\Sigma\)35} & \multirow{2}{*}{\(\Sigma\)35} & \multirow{2}{*}{\(\Sigma\)35} & \multirow{2}{*}{\(\Sigma\)35} & \multirow{2}{*}{\(\Sigma\)35} & \multirow{2}{*}{\(\Sigma\)35} & \multirow{2}{*}{\(\Sigma\)35} & \multirow{2}{*}{\(\Sigma\)35} & \multirow{2}{*}{\(\Sigma\)35} & \multirow{2}{*}{\(\Sigma\)35} \({}^{\pm}\) 1.17 & & & \\  & & & 95\% CI & 2.24–2.62 & 2.37–2.79 & 2.47–2.82 & 2.29–2.63 & 2.38–2.68 & 0.20 \\ \cline{1-1}  & & & range & 0.38 & 0.42 & 0.35 & 0.34 & 0.30 & & \\ \hline \hline \end{tabular}
\end{table}