## 4 Discussion
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & & \multicolumn{3}{c}{**Age**} \\ \cline{3-5}  & & **Age \textless{} 33 (_n_ = 136)** & **Age \textless{} 33 (_n_ = 136)** & \(p\) \\ \hline
**Horizontal (0.8 mm)** & Mean \(\pm\) Sd & \(-53.17\pm 17.16\) & \(-53.25\pm 16.48\) & \({}^{\text{a}}\)_0.969_ \\
**Change Ratio (\%)** & Median (Min–Max) & \(-56.1\) (\(-82.6\)–\(13.6\)) & \(-57.1\) (\(-78.7\)–\(11.4\)) & \\ \hline
**Horizontal (2.8 mm)** & Mean \(\pm\) Sd & \(-32.34\pm 16.32\) & \(-34.34\pm 16.46\) & \({}^{\text{a}}\)_0.255_ \\
**Change Ratio (\%)** & Median (Min–Max) & \(-33.3\) (\(-65.4\)–\(14.8\)) & \(-36.1\) (\(-100\)–\(15.4\)) & \\ \hline
**Horizontal (4.8 mm)** & Mean \(\pm\) Sd & \(-23.60\pm 20.29\) & \(-23.30\pm 17.92\) & \({}^{\text{a}}\)_0.920_ \\
**Change Ratio (\%)** & Median (Min–Max) & \(-22.4\) (\(-100\)–\(33.6\)) & \(-23.1\) (\(-100\)–\(27.4\)) & \\ \hline
**Horizontal (6.8 mm)** & Mean \(\pm\) Sd & \(-18.85\pm 24.14\) & \(-19.33\pm 26.57\) & \({}^{\text{a}}\)_0.806_ \\
**Change Ratio (\%)** & Median (Min–Max) & \(-15.9\) (\(-100\)–\(29.2\)) & \(-15\) (\(-100\)–\(42.5\)) & \\ \hline \hline \end{tabular} \({}^{\text{a}}\) Mann-Whitney U test.  
\end{table} 
Table 5: Evaluation of the changes in horizontal measurements by age groups. the symmetrical toothed side when evaluating the reduction in alveolar bone width was to keep the effect of resorption mechanisms that may result from individual differences to a minimum. The reduction in alveolar bone width reaches the maximum in the first 12 months after tooth extraction, and this resorption rate decreases after the first year [5]. Therefore, individuals who underwent tooth extraction 13-23 months ago were included in this study. In this way, we tried to keep the effect of the time that had elapsed after tooth extraction on resorption to a minimum. Orthodontic treatment can be conducted alone or in combination with other treatment options to ensure skeletal/dental canine and/or molar relationships in individuals with missing teeth [22]. Although it may vary according to the existing malocclusion and the characteristics of the missing tooth region, in individuals with midline deviation and/or crowding, mesialization or distalization of the teeth can be performed both to correct the malocclusion and to disguise the missing tooth [23]. [PERSON] and [PERSON] et al. showed a decrease in alveolar bone width after orthodontic tooth movement [24; 25]. [PERSON] et al. and [PERSON] showed that the risk of an alveolar defect and root resorption increases in cases with orthodontic tooth movement toward edentulous areas with insufficient bone width compared to root width. They also revealed that in orthodontic tooth movements in the anterior regions of hyperdivergent patients, edentulous ridges with a smaller bone width limit the orthodontic tooth movement and increase the incidence of bone loss [15; 26]. [PERSON] et al. reported that orthodontic tooth movement in cases with an insufficient bone width increased the incidence of bone dehiscence, mostly in the buccal cortex [27]. [PERSON] et al. showed that orthodontic tooth movement is associated with the alveolar bone width/root width ratio, and as this ratio increases, orthodontic tooth movement also increases. They also reported an inverse relationship between bone density in the buccal cortex and orthodontic tooth movement and stated that optimum tooth movement can be achieved in cancellous bones with a lower density [28]. It has been revealed that tooth movement obtained in cortical bones with forces applied within normal limits will be slower than cancellous bones, and excessive forces that are applied to increase movement will increase the risk of hyalinization and root resorption [28]. The null hypothesis of this study was rejected.